Home Chemistry

Bose-Einstein Condensate

2012-01-09T12:32:00.000-05:00

I'm writing up a project for the forthcoming GeekMom book that involves states of matter. Here's one I seem to have missed: Bose-Einstein Condensate. First created in 1995, it is not yet widely known or taught in schools. But an old page from website of the University of Colorado at Boulder actually does a pretty good job of explaining BEC in words and animations simple enough for kids to understand.

And for all you educators out there, here's an interesting debate on the NSTA website on if and when teachers should share the news that there are more states of matter out there than just solid, liquid and gas...

Interested in Robotics?

2011-12-08T09:21:00.001-05:00

I've been hard at work on a new activity book for kids from Nomad Press. It's called Robotics: Discover the Science and Technology of the Future and includes projects from a range of area -- including chemistry! I'll be starting a companion blog to the book as soon as the writing is done.

In the meantime, check out news about the book and robotics in general on my new Facebook page!

Zombie Marie Curie

2011-05-30T09:00:00.001-04:00

http://xkcd.com/896/

A worthy follow-up to Zombie Richard Feynman. And for more on Marie Curie, read the new illustrated biography Radioactive with the cool glow-in-the-dark cover! (Review coming.)

Plasma Experiments on "Integrated Science"

2011-05-23T15:16:00.000-04:00

We've been doing some amazing plasma experiments over on our current blog, Integrated Science at Home. If you haven't visited, come take a look!

Homemade Lava Lamp -- New and Improved!

2011-05-16T09:00:00.012-04:00

We recently tried a new and improved version of the lava lamp project from several years ago. It worked great! Here's how we did it:

Tools and Materials:
• Clean recycled soda or water bottle, label removed, 16 oz or larger
• Water
• Food coloring
• Baby oil, at least one 12 oz bottle
• Effervescent antacid tablets (such as Alka-Seltzer)
• LED push light (or make a light-up base from a recycled jar or can, some extra bright LED bulbs, coin batteries, and tape)
• Plastic plate or other protection for table
• Cooking (meat) thermometer (optional)

Step 1: Prepare the lava lamp bottle. The first step in building your homemade lava lamp is to find a tall, thin, clear bottle. Any size or shape will do. A plastic bottle, such as a recycled soda or mineral water bottle, will eliminate worries about breakage if it falls. We used a 16-ounce bottle, which is large enough to get the full floating blob effect, but only requires one 12-ounce bottle of baby oil. A larger lamp bottle will last longer but you’ll need more baby oil to fill it. Rinse the bottle clean and remove any labels. A glue solvent like “Goo Gone” can make scraping off a tough label easier.

Step 2: Prepare the Bottom Layer of Colored Water.
Once you’ve got your bottle ready you can begin filling it. The exact chemical formula used to make real lava lamps is a trade secret (although the UK manufacturer Mathmos has a cool video on its website showing the lamp being assembled). But as with the egg timer which inspired it, the gooey “lava” is actually a type of wax. And the way it slowly floats up and drifts down has to do with the balance between the density of the wax and the density of the liquid it floats in.

Density tells us how much of a substance is contained within a certain volume, or amount of three-dimensional space. The higher the density, the more stuff is in there. And density can change with temperature. For instance, at room temperature the wax in a lava lamp is denser than the liquid, so it sits at the bottom of the lamp. When the light is turned on and the wax warms up, it begins to melt and spread. As the volume of wax in the lamp grows, its density decreases, because the same number of molecules are now taking up more space. At the point where the wax becomes less dense than the liquid, it starts to float to the top of the lamp. Eventually the wax at the top, away from the hot light, starts to cool. As it becomes denser, the wax sinks down, is warmed by the light, and the cycle repeats itself in a colorful mesmerizing display.

Our homemade version uses water and oil, but the principle is the same. Oil is less dense than water, so the water in our lamp sinks to the bottom, while the oil floats to the top. When we introduce a less dense gas into the water, bubbles form that carry some of the water slowly up through the oil. By coloring the water with dye, we can approximate a lava lamp-type effect that lasts several minutes.

If spilling food coloring or oil is a concern, place your bottle on a plastic plate or other protected surface. (They can also stain clothing, so old clothes or an apron may be advisable.) Fill the bottle about one quarter full with water. Add 3 to 4 drops of liquid food coloring for a 16-ounce bottle, or more for a larger bottle.

Before you shake up the bottle to mix the food coloring, take a few moments to watch as the dye begin to spread in vibrant tendrils of color, all on its own. That seemingly spontaneous, random movement is called Brownian motion, after the botanist Robert Brown. In 1827, Brown looked at grains of plant pollen in a drop of water through a microscope and noticed that they jiggled around. In 1905, Einstein suggested that the pollen grains were moving because they were colliding with molecules of water, and predicted that the way the grains moved could be used to figure out how many molecules of water there were. Scientists later showed that Einstein’s prediction was correct -- one of the first proofs of the existence of atoms and molecules.

Once you’ve mixed up the food coloring and water as evenly as possible, by shaking, stirring, or just letting Brownian motion do its thing, check to see if you need to add any more dye. To get the lava lamp effect to work, you want the water to look pretty dark. But don’t go overboard at this point. If necessary, you can add more food coloring later on in the process.

Step 2: Add the Top Layer of Oil.
Now that you’ve got your colored “lava” layer ready, it’s time to add the clear liquid. We use baby oil, which is colorless and available pretty much anywhere. Baby oil is mostly mineral oil -- a non-toxic byproduct of the manufacture of gasoline, used to lubricate cooking tools and to make gummy candy -- with a little fragrance added to make it smell nice. Compared to cooking oil, baby oil is also inexpensive. I picked up a 12-ounce-size bottle, enough for one 16-ounce homemade lava lamp, at my local dollar store. Of course, you can use any kind of cooking or skin care oil you have on hand, as long as it’s not too dark to see through.

Pour the oil into the lava lamp bottle slowly, stopping when you reach the bottle’s shoulder. You’ll want to leave a little head room so the lamp solution doesn’t bubble over. Let the bottle sit for a minute or two, so that the contents settle into two layers: colored water on the bottom, oil on top, with a nice sharp line in between.

Here’s where density comes in. As already mentioned, oil is less dense than water, so the same volume of oil weighs less than an equal volume of water. In scientific terms, the specific gravity of mineral oil – or the ratio of its density compared to the density of water – is about 0.8 to 1. However, there’s another reason that oil and water form two neat layers, and it has to do with the bonds that make molecules stick together with other molecules.

If you could see a water molecule, you’d notice two little hydrogen atoms sitting on top of a bigger oxygen atom like the ears on Mickey Mouse’s head. Those “ears,” which each have negatively-charged electrons whirring around them, give that end of the water molecule a slightly negative charge. That makes water a type of polar molecule. Just like magnets, the negative end of polar molecules is attracted to the positive end of other polar molecules. Oil molecules, on the other hand, are non-polar. They’re made up of long chains of carbon and hydrogen atoms, which don’t have a charged side. Non-polar molecules will form bonds with other kinds of non-polar molecules (“like dissolves like”), but when put together with polar molecules, they keep to themselves. So when people say “oil and water don’t mix,” what they’re really talking about is molecular polarity!

Step 3: Set up the lights.
So far you’ve built what science teachers call a density column – one type of substance floating on another. To turn it into a lamp, you need to add a base with a light source. A small battery-powered LED push light is ideal. These look like discs with three or four LED bulbs embedded in them. You can find inexpensive versions in the flashlight section of your local dollar store or discount mart. Just set the LED push light on your plate or protected surface, and carefully place your lava lamp bottle on top so that the liquid inside is lit up.

If you can’t find one of these handy lights, you’ll have to make your own base. A large sturdy plastic jar or a can should work fine. Arrange some new or re-used LED bulbs inside. To power them, slip a button battery between the wires of each LED bulb and tape in place.

Step 4: Start the action!
Unlike real lava lamps, which run on the heat of a light bulb, our homemade lava lamp is powered by the energy released when you drop an effervescent (fizzing) antacid tablet like Alka-Seltzer into water. You’ll probably have to break the tablet in half to fit it in the opening of the bottle, but try to use as large a piece as possible. The bigger the piece, the more dramatic the effect!

As the tablet hits the layer of water at the bottom of the homemade lava lamp, it begins to release bubbles of gas. Because gases have a lower density than liquids, the bubbles float slowly upward through the thick layer of oil, carrying drops and blobs of water along with them. But when the bubbles reach the surface, the gas continues rising, while the denser water that’s left behind drifts back down to the bottom of the lamp. The lava lamp effect will continue as long as the tablets are fizzing. You can keep adding pieces of antacid tablets to prolong the show, until the oil gets too cloudy to see through.

What’s happening when the tablet begins to fizz is actually the same chemical reaction as the classic baking soda-and-vinegar volcano. Fizzing tablets contain an acid (powdered citric acid, which gives lemon juice its sour taste) and a base (sodium bicarbonate, our old friend baking soda). Acids are compounds with an excess of hydrogen (H+) ions, or hydrogen atoms that are missing their electron and have a positive charge. Bases have a surplus of hydroxide (OH-) ions, which are negatively-charged molecules of oxygen and hydrogen. Strong acids and bases are highly reactive – they’ll combine with, and start to dissolve, many types of material, including your clothing and skin. But put them together in the right amounts and they’ll neutralize each other to produce water! (H+ and OH- make H2O.) When fizzing tablets react, they also produce a salt (in this case, sodium citrate) and carbon dioxide (the gassy bubbles).

Know what else is cool? The reaction of fizzing tablets and water creates an endothermic reaction. That means that those chemical changes are pulling heat out of the surrounding water to use as fuel. So as it’s fizzing, your lamp is dropping in temperature. Try sticking a cooking thermometer in your bottle to see if you can detect the change in temperature. (You might want to skip the lights, since they may give off a small amount of heat energy.)

Flower Chemistry

2010-11-13T14:56:00.000-05:00

Over at GeekMom, we've gotten some great responses to Mythbuster Kari Byron's post about getting kids excited by science. One commenter, who only gave the name "OrchidGrowinMan," provided directions for a flower chemistry party he organized for his daughters. It sounds so interesting, I thought I'd share it here. Maybe we'll get to try it sometime ourselves.

Years ago, I hosted a “Science Party” for my eight-year-old daughter to test flowers from our garden for acid/base color indicators. Ten of her friends came over, and spent HOURS at it, skipped lunch (!) and some had to be dragged away. The agenda was to gather flowers and such from the gardens and greenhouse (orchids too!) and smoosh them in a mortar and pestle with a bit of rubbing-alcohol (When I was a teenager, I experimented and found this to be the BEST solvent for this purpose). Then a dropper could suck-up the (usually) colored solution to put a few drops into each of three tubes, adding acid to one, water to one, and alkali to the third. I had bought each of them a set of safety goggles, plastic droppers and a rack of 25 little plastic test-tubes to take home (surplus).

Some surprises came up, like the prevalence of flavonoids that turn yellow with strong alkalis (so some samples go red-purple-blue-green with increasing pH). They're the reason why when you wash your hands after handling tomato plants the soap turns yellow: You can easily collect lots of some weird pigment by stroking tomato stems with a cotton-ball, and it turns bright greenish-yellow in alkali.

Materials were obtained from American Science & Surplus at good prices:
American Science & Surplus
3605 Howard street,
Skokie IL 60076
(847) 982-0870
http://www.sciplus.com/

List of Materials

Safety Goggles $2.25 ea.
Test Tubes (at least five) $1.75 ea.
Test Tube Rack
Mortar and Pestle $13.95 ea.
Droppers Provided $2.00/20.
Acid: distilled vinegar, lemon juice
Alkali: household ammonia, baking soda
Solvent: rubbing alcohol
Apron or Lab Coat Recommended
Pigmented plant parts: flowers, berries, pods.
Acidic foods like fruits, alkaline like soda- or shortbread or cake.
Miscellaneous, if available and needed: Ph Meter, Litmus paper, Acid/base indicators, tincture of iodine

What Will We Do:
1. We will do experiments to try to extract the colours from plant parts like flowers, leaves and fruits.
2. We will then determine if these chemicals change colour when they are mixed with acids and alkalis. That is, are they acid/base indicators.
3. Using any acid/base indicators we find, we will try to identify whether some foods are acidic or alkaline (basic).

Procedures (The three experiments can be run concurrently):

Experiment 1

Obtain a pigmented plant part, the darker the better. The dryer the better. If possible, cut away any uncoloured parts.
Smoosh and Goosh it up in a mortar and pestle.
Add a little rubbing alcohol and carefully grind it up some more.
Pour, or use a dropper to remove the liquid to a test tube. Label the tube. What does it look like?
Wash the mortar and pestle and repeat.

Experiment 2

Put a few drops of the extracted pigment from experiment 1 into each of five test tubes.
Put three drops of ammonia or baking soda solution in the left test tube. What happens?
Put three drops of vinegar or lemon juice solution in the right test tube. What happens?
Put one drop of ammonia or baking soda solution in the next to left test tube, and two drops of water. What happens?
Put one drop of vinegar or lemon juice solution in the next to right test tube, and two drops of water. What happens?
Put three drops of water in the center test tube. Compare the colors of each sample.
Put a few drops of the extracted pigment from experiment 1, one that changes colours, into each of five test tubes.
Put three drops of ammonia solution in the left one, three drops of baking soda solution in the next. What happens?
Put three drops of vinegar in the right one and three of lemon juice solution in the next. What happens?
Put three drops of water in the middle tube. Compare the colours.
Using the results of the experiment above, if you add a drop of vinegar to the left (ammonia) tube and a drop of water to the middle one, and a drop of ammonia to the right (vinegar) tube, how many times do you have to repeat to get them the same colour?

Experiment 3

Obtain a food (or other material) sample.
Put a few drops of the extracted pigment from experiment 1, one that is shown to be an indicator, onto the sample. What happens. Is the sample acidic or alkaline?

Why Does That Happen?
The pigments in plants fall into one of several chemical families. Blue, purple, pink, and most red colours are due to the presence of one or another of the anthocyanin pigments, which are acid/base indicators. [antho means “flower,” cyanin means “blue.”] Their molecular shape changes in response to acidity, and this changes their colour. Some blue flowers have the same anthocyanin pigment as some pink ones; the difference is in the acidity/alkalinity (pH) of the plant juice. Vinegar and lemon juice are acidic, ammonia and baking soda alkaline. Float flowers in them and the flowers will likely change colour.
Anthocyanins are soluble in water and alcohol and are easy to extract, They also are usually easily destroyed by heat (cooking). Beets and chard (and cacti) have pigments in a different group, betacyanins, which are more heat stable and are also (barely) indicators. [Beta means “beet.”]
Yellow, orange and some red pigments (as in tomatoes) are due to carotenoid pigments, which are not acid/base indicators, and are not really soluble in water and sparingly in alcohol. [carota means “carrot”] Green chlorophyll and various brownish pigments may also be present.

There are other experiments that can be done: baking soda combined with an acid makes bubbles (carbon dioxide), tincture of iodine from the medicine cabinet gives a black/blue colour on starch and can be used to detect starchy foods and where in a plant starch is stored.

Now Blogging at GeekMom with Mythbuster Kari Byron!

2010-10-03T00:49:00.000-04:00

I've been busy the past few months helping to launch GeekMom, a site dedicated to moms who want to share their geeky passions with their kids. To start us off, we've got MythBusters host Kari Byron writing about her new adventure as mom to a one-year-old girl. Kari is also the host of the new hour-long kids' show Head Rush. Check us out!

And I'll still be blogging at GeekDad, so be sure to stop by there too!

The Buckyball is 25 today!

2010-09-04T11:02:00.001-04:00

Google's animated doodle alerted me to this milestone in modern chemistry. Buckyballs, discovered in 1985, are carbon molecules that are exceptionally strong and light. They're used in carbon fiber bike frames and a whole host of other cutting edge products. We saw the original inspiration, Bucky Fuller's geodesic dome, on a trip to Montreal.

Check out my post on GeekDad.

Discover Magazine is Looking for Home Experiment Videos!

2010-05-10T18:32:00.000-04:00

Unfortunately, all our best videos are just a couple seconds long. But if you're interested:

DISCOVER is currently producing a Web TV show about home science experiments and demonstrations, and we're looking for submissions—the most enlightening, visually impressive, surprising, or just plain funny videos out there. Submit your video below (it's OK if you've already uploaded it elsewhere on the Web) and we'll select the best ones for the show. (Winners will of course be identified.)

For more information, go to the Discover Magazine website.

Lots of Periodic Tables

2010-04-09T11:13:00.001-04:00

Just a pointer post to an interesting post by my fellow GeekDad writer Nathan Barry on some creative versions of Periodic Tables, including illustrator Russell Walks' cool-looking Periodic Table of Imaginary Elements.

Salt Crystal Trees

2010-03-21T22:48:00.001-04:00

I just did a class on The Chemistry of Crystals for a local elementary school's Saturday Scholars program where we did the Salt Crystal Garden project I did with my kids in 2007. In addition to using cubes of kitchen sponge as a base, we used cardboard toilet paper tubes to make Salt Crystal trees. Since the crystals were just starting to form by the time the class was over, I tested the project out the day before to make sure it would work. It took a while to get going, but the result was pretty spectacular.

The formula we use is an adaptation of the one found on the website for Mrs. Stewart's Bluing. Bluing is a colloidal suspension of very fine blue iron powder in water. Its actual purpose is make laundry white! Although I've listed the changes we made, I never gave the final version of the directions, so here they are:

Materials

• porous base, such as a sponge or cardboard toilet paper tube
• Water: Distilled water is better than tap water.
• Salt: Plain, iodine-free pickling salt works better than table salt.
• Ammonia (NH3): Optional. Irritating to eyes and toxic. Use plain ammonia, not ammonia cleaners.
• Laundry Bluing: Bluing, a suspension of tiny particles of Prussian Blue (Ferric Hexacyanoferrate), makes clothes look whiter by tinting them slightly blue, among other uses. Mrs. Stewart's Bluing is a brand sold in some supermarkets or online at www.MrsStewart.com.
• Plastic cup and plastic spoon: For mixing chemicals. Throw them away when done.
• Disposable plastic bowl: To hold your garden.
• Liquid food coloring.

NOTE: I outfitted the kids with rubber gloves and safety goggles, to make things more scientific.

1. For the sponge, wet with water and wring it out. Cut it into 1-inch sized pieces. Lay them in the bowl. Or cut the top of the cardboard tube into strips and bend them to look like tree branches. Stand the cardboard tube in the bowl.
2. In the cup, mix equal amounts (1 or 2 spoonfuls each) of salt, ammonia, and bluing. Stir until dissolved. For cardboard base, also add an equal amount of water.
3. Pour over the sponge or around the base of the tube. Try to keep it away from the sides of the bowl.
4. Sprinkle on 2 more spoonfuls of salt.
5. Add some drops of food coloring where desired.
6. Garden should start growing in 1 hour, depending on materials and humidity.
7. The garden will keep growing for several days. You can keep adding more salt and more solution. To make it last, don’t knock it or let it get blown, because the crystals will collapse.

Update: I've been adding more water to one of the crystal trees but not the other. Look at the difference in how they've developed. The tree that was watered is spiky, while the other is puffy!

A Little Nanoscience Cross-Posting

2010-01-25T08:51:00.001-05:00

We did one of the nanoscience experiments from NISE Net and posted it on Home Physics. This bit of Kitchen Nanoscience demonstrates how difference in scale affects forces like gravity. It's quick and easy, if you've got some dollhouse or LEGO-sized drinking vessels around!

Home Chemistry in Chemical & Engineering News!

2010-01-25T08:47:00.002-05:00

As promised, Chemical & Engineering News has an article mentioning our hand warmer experiment. Check it out!

What's That Stuff? The Chemistry of Everyday Products

2010-01-04T17:36:00.000-05:00

I was just interviewed for the What's That Stuff column of Chemistry & Engineering News, the weekly magazine of the American Chemical Society. Apparently, this blog is the first thing that comes up when you Google "chemistry" and "hand warmers." How cool is that! Looks like they have some interesting articles too. Can't wait to see it!

Home Chemistry Experiment Links

2010-01-02T10:27:00.001-05:00

I've started a new category in my sidebar for links to chemistry experiments you can easily do at home. They include some activities from NiseNet, the Nanoscale Informal Science Education website. While these are designed for museums and schools, many of them are easy to do at home too. I've already printed out the paper model Bucky ball to try later!

The Oxford Book of Modern Science Writing

2009-12-14T22:37:00.003-05:00

According to my fellow GeekDad contributor Jenny Williams, The Oxford Book of Modern Science Writing --Richard Dawkins' collection of essays by science writers famous and obscure on everything from astronomy to biology, genetics, evolution, chemistry and relativity-- is "400 pages of science-y goodness."

Read her review here.

ChemMatters podcast - Nanostructures

2009-11-16T23:12:00.003-05:00

From the ByteSize Science blog of the American Chemical Society:

The award-winning high school chemistry magazine ChemMatters is making its YouTube debut with its first ever video podcast. The first episode highlights the very big promise of those very small machines known as nanotechnology. The episode explains how incredibly small nanostructures like buckyballs could lead to tiny devices that bring medicine exactly where it needs to go in your body, as well as powerful computers the size of a grain of sand or vital new sources of energy.

Theo Gray's new book, The Elements

2009-11-08T11:17:00.004-05:00

Here's what I said about it on GeekDad's first holiday gift guide:

The Elements: A Visual Exploration of Every Known Atom in the Universe
Even if this book weren’t absolutely gorgeous, it would still be a worthwhile investment because of how well it works as Coffee Table Education. This is when you leave a book lying around that is so tempting the kids pick it up and start learning stuff without even being asked! Based on author Theodore Gray’s amazing website, The Elements offers a double-page spread (or sometimes more than one) on each element, complete with lush photos of the raw material in its pure form, as well as in various incarnations, both common and rare. Delightful. Buy it on Amazon.

New Blog - Home Physics!

2009-10-04T14:06:00.000-04:00

It'll be a few more weeks before it really gets up and going, but I'm starting to add helpful links and info about learning physics at home to this year's science blog, Home Physics. Come visit! And feel free to comment with your favorite resources or suggestions.

Make Magazine's New Science Room for Hobbyists

2009-09-15T15:38:00.003-04:00

From the website of Make magazine comes the Make: Science Room, a fun and useful resource. Here's what they say about it:

We hope you'll use it as your DIY science classroom, virtual laboratory, and a place to share your projects, hacks, and laboratory tips with other amateur scientists. Your Make: Science Room host is Robert Bruce Thompson, author of Illustrated Guide to Home Chemistry Experiments: All Lab, No Lecture. (Make: Books, 2008) and Illustrated Guide to Forensics Investigations: Uncover Evidence in Your Home, Lab, or Basement (not yet published). We'll be drawing material from these titles first, but will soon branch out into biology, astrononmy, Earth sciences, and other disciplines. We'll be adding lots of material on a regular basis, so check back often. For more info on the site, see Introducing the Make: Science Room.

They also have a new science lab section in Maker Shed, their online catalog, for basic equipment. Looks neat!

Stocking up for Fall

2009-08-07T08:53:00.003-04:00

If you're starting to buy supplies for homeschooling in the fall, Home Science Tools is offering free shipping on orders over $100 using code PAUG89. I've also seen, but haven't verified, that you can get $1 shipping on orders over $50 using code PCAT89 through Aug. 31, 2009.

The Chemistry of Colored Bubbles

2009-06-26T12:51:00.004-04:00

Zubbles are colored bubbles. And to see what went into their making, there's an interesting PopSci article from a few years back.

A Science Comedian Talks About Helium

2009-05-15T08:06:00.002-04:00

Here's a little five-minute slideshow presentation by Science Comedian Brian Malow on how market forces affect the world's second most prevalent element:

Periodic Table Guy's New Book

2009-04-29T10:43:00.003-04:00

If you aren't a regular GeekDad reader, be sure to check out my review of Theodore Gray's new book, Mad Science. Gray is the guy who built an actual periodic table, with legs and everything, including compartments in which he keeps samples of every element. His website is a treasure trove of information about different chemicals and things you can do with them!

Hey Homeschoolers! I Need Your Help...

2009-03-29T23:31:00.001-04:00

A commenter over at GeekDad (where I am now one of two homeschooling mom contributors!) wanted to know if there were any geeky (science and tech oriented) homeschooling blogs. What are your favorites? Please comment!

UPDATE: The GeekDad post is here. Somehow I think I missed a few good ones, but I'll try to add them to the sidebars of my blogs soon.

A Chemist Bakes the Perfect Cookie

2008-12-19T13:47:00.004-05:00

Food Scientist Shirley Corriher's tips for baking perfect cookies seem to be everywhere at the moment. On National Public Radio, her advice for crumbly cookies is to add a tablespoon of water to a cup of flour. That will make the proteins — glutenin and gliadin — hold together. In the New York Times she's one of several culinary experts weighing on why you must keep butter cool.

Butter is basically an emulsion of water in fat, with some dairy solids that help hold them together. But food scientists, chefs and dairy professionals stress butter’s unique and sensitive nature the way helicopter parents dote on a gifted child.

Although I have not heard of Corriher before, I am tempted to check out her new book Bakewise: The Hows and Whys of Successful Baking with Over 200 Magnificent Recipes. Amazon customers give it some rave reviews.

And I like the chemistry angle too.

Cake in a Mug mug

2008-12-12T14:59:00.005-05:00

When I couldn't get carbon snakes to work, I made exploding cake in a mug. And for a last-minute holiday gift, I just put the barebones recipe on a mug, complete with crudely drawn illustrations. You can order them too from Cafe Press. Order by Monday for holiday delivery.

Homemade Ice Cream

2008-12-06T23:49:00.004-05:00

We had homemade ice cream for dessert on Thanksgiving. (My dad, never having seen our machine, asked, "Whose home was the ice cream made in?") But the machine we have uses a cooling pan with some kind of chemical sealed inside. You put the pan in the freezer before using it, then just add the ingredients and let the machine stir them up. Not much to it.

Meanwhile, over at Socks and Books, homeschoolers "Moomintroll" and "Snufkin" recently made ice cream the old-fashioned way, using rock salt and ice cubes. We did this years ago using two plastic bags, but they used a metal pot, which I think looks way more dramatic.

Go to their post to see how its done, complete with chemistry explanation. I'm saving this link for future reference!

Chemistry in the Community online textbook

2008-11-30T10:00:00.004-05:00

I came across a discussion on a homeschool email list of the American Chemical Society's high school textbook Chemistry in the Community (ChemCom) and thought I'd throw it out there for anyone interested. The textbook is muy expensive, but there's a companion website with supplementary student material, including animations, that might be useful even if you don't use the text.

And just a reminder that ACS hold Chemistry Week activities every October, and their website has a page of educational content, including simple experiments for kids.

MAKE's Chemistry Gift Guide

2008-11-24T07:53:00.003-05:00

At the MAKE magazine website they have a well-rounded if nostalgic collection of chemistry books and sets for "the next generation of chemists." A lot of glassware if you're into that sort of thing; I was very happy using plastic cups and spoons. Worth browsing.

(And if you want to send my family a little holiday cheer, and maybe save a little money, come back here and buy the items you see at MAKE from my Amazon store. Those little kickbacks I get when you click through from my websites are appreciated!)

The Thames and Konos Chem C3000 chemistry set -- probably the best you can buy at the moment, though still less complete than chemistry sets of the 50s and 60s -- is $50 cheaper at Amazon.

Carbon Snakes

2008-11-06T11:30:00.009-05:00

Here's a project I neglected to post last spring. We weren't totally satisfied with the results, so it never made it into the blog. Just this week, however, I found something fun to add, so I'm putting it up now for the record.

This experiment, like so many we did last year, came from Anne Marie Helmenstine at About.com's Chemistry page. Here's what we did:

Baking Soda and Sugar Carbon Snake

Sand

lighter fluid

baking soda

powdered sugar

Mix 4 tsp sugar and 1 tsp baking soda.
Make a mound with the sand. Push a depression into the middle of the sand.
Pour the alcohol or other fuel into the sand to wet it.
Pour the sugar and soda mixture into the depression.
Ignite the mound, using a lighter or match.

Anne Marie goes on to write:

At first, you'll get a flame and some small scattered blackened balls. Once the reaction gets going, the carbon dioxide will puff up the carbonate into the continuously extruded 'snake'. Actually, you don't even need the sand. I tried this project using baking soda and sugar in a metal mixing bowl, added the fuel, and lit the mixture. It worked fine. The old firework snakes had a distinct smell. These have a smell too... burnt marshmallows! If you use pure ethanol, sugar, and baking soda, then there is nothing toxic about this project. One caution: Don't add fuel to the burning snake, since you risk igniting the alcohol stream.

We got the puff balls, but the snakes were kind of stumpy. If you watch the video, you can see that the level of anxiety over this experiment overshadowed the excitement as well:

Here's how Anne Marie explains the reaction:

How Black Snakes Work
The sugar and baking soda snake proceeds according to the following chemical reactions, where sodium bicarbonate breaks down into sodium carbonate, water vapor, and carbon dioxide gas while burning the sugar in oxygen produces water vapor and carbon dioxide gas. The snake is carbonate with black carbon particles:
2 NaHCO₃ -> Na₂CO₃ + H₂O + CO₂
C₂H₅OH + 3 O₂ -> 2 CO₂ + 3 H₂O

Kitchen Biology

2008-10-20T00:28:00.004-04:00

Many of the chemistry projects that we never got to last year lend themselves to investigation under the heading of biology as well. Although I haven't seen the term "Kitchen Biology" used as often as "Kitchen Chemistry," I've got plans to brew (root) beer (with yeast), make yogurt (with bacteria), and grow bioluminescent bacteria on old fish. Good times ahead!

Be sure to visit my Home Biology blog.

Wood Sorrel

2008-09-09T11:40:00.002-04:00

We've been cataloging plant and animal species in our backyard for biology studies and discovered that wood sorrel has a sour, lemony taste to the leaves because of oxalic acid. This acid is also present in many other fruits and vegetables; in fact, according to Wikipedia, if you eat a slice of rhubarb pie with a glass of milk, it will cause some of the calcium to precipitate out, creating tiny grains you can feel on your tongue!

Moving on to Home Biology

2008-09-06T17:52:00.002-04:00

The summer has gone and I am starting to add content to this year's science blog, Home Biology. Come join me!

Periodic Table of Videos

2008-08-03T20:30:00.003-04:00

Still hoping to do a few outdoor experiments before the summer's over but work -- and unending days of rain -- are making it difficult. Maybe this week...

In the meantime, fellow homeschooling author and blogger Kris Bordessa has post on the Periodic Table of Videos from the University of Nottingham in England. The short videos are hosted by Martyn Poliakoff, research professor and pioneer in the field of green chemistry -- with the best Mad Scientist hair I've seen in a long time!

Kris says her 15 year old spent an hour poring through this site. Check it out!

Chemistry Simulations vs Hands-On

2008-07-13T17:34:00.008-04:00

Note: I'm hoping to post at least a couple more experiments here -- one that we are still trying to get to operate as advertise -- before turning our attention to biology for the coming school year. (I've just set up homebiology.blogspot.com in anticipation!)

But in the meantime I'd like to pass along an email my friend and fellow homeschooling parent Paul Fernhout sent our local homeschool email list today with some thoughts on chemistry simulations:

In regard to something else I am looking into, I found a website today I wanted to share by Professor William J. Vining at the State University of NY at Oneonta. He has helped develop free chemistry simulations that should run in most web browsers with a Shockwave/Flash plugin installed. At least most of the first five or ten simulations in the list at that URL should be easy enough to play with about some basic ideas of chemistry (the periodic table, etc.). I think the simulations all go with a specific text book, but the general concepts would apply for any person interested in chemistry even without a specific textbook. Essentially, these are all safe scientific toys which may (or may not) in turn inspire further interest in the topic of chemistry. So, think of most of them more as chemistry puzzles (what could they mean?) than chemistry instruction.

From Prof. Vining's main page:

My principal interest lies in developing and testing educational materials and methods for chemistry. The materials are primarily computer-based multimedia software systems that serve the dual purpose of simulating the exploratory nature of chemical investigation and also make use of graphical advantages of computer systems to better explain chemical concepts. The focus of these programs is to enable students of chemistry to explore chemical concepts in a manner that leads them to discover those concepts independently. Because chemical concepts are based on analysis of experimental results, the software systems we design are centered around presenting the student with information they would obtain from an experiment, along with computer-based tools for analyzing those results. This allows the student to observe trends and choose the appropriate experiment to answer a particular question. Once an area of chemistry has been presented by an interactive experimental simulation, the concept can then be explained using multimedia tools such as videos and animations. Our work involves preparation of materials appropriate for use in general, organic, inorganic, physical, and analytical chemistry. Recent projects have included work on a CD-ROM textbook for general chemistry and currently we are working on modules for organic chemistry.

He has some other resources linked from his main page, like some videos of mixing chemicals (though the one I tried did not play well for me). He also has some downloadable things (for Windows?) I did not try.

The Concord Consortium is another site with high quality free learning resources related to chemistry and other things as well, including for example CC Atoms. But some of these resources are harder things to try as they require Java and perhaps locally installing some things. Many (but not all) of these resources are designed for college courses, but could be fun to just play with for someone interested in chemistry who at least knew a bit to get
started with.

A chemistry simulation is definitely IMHO a good use of computers for older homeschoolers, since real (sometimes dangerous) chemistry sets are hard to get these days, making chemistry otherwise difficult to really explore in detail at home. There are some nostalgia and warnings there in the comments about old chemistry sets by the way (some had radioactive materials). There is a link in the comments to that blog post to a supposedly interesting set at Edmunds Scientific. But that set is $200 and obviously is going to take some supervision and pose some risks.

Scientific Explorer's Fizzy Foamy Science Kit of Safe Chemical Reactions is an example of a ($20) "safe" chemistry-related set we got for our child (age four) but it mostly just has stuff you'd find around the house like oil, baking soda, and vinegar (except maybe citric acid in pure form): "
A container of oil in it had leaked all over everything when we got it, but it cleaned up easily. It has some scientific looking stuff in it (not sure if it would be cheaper to buy it separately), but is probably not very interesting for older kids for that long.

The simulations let you try to do all sorts of things, although may be mainly of interest to older kids since they are more abstract (that is, no fizzing). Obviously, like all simulations, they are still not the same as the real thing, being worse in some ways and better than others. They will help kids get the intellectual challenge of chemistry, but they won't help them gain a sense of confidence in a lab setting they would get with the real stuff. But even if you had the real stuff, I'd suggest the simulations could still be interesting (perhaps even more interesting for a motivated learner).

Thanks, Paul!

Photosynthesis

2008-06-16T20:39:00.003-04:00

I've been subbing in the public schools the last couple months (quite an experience after 10 years of homeschooling, but that's another story). Last week I had to go over plants with a class of third graders and then give them a test.

In the review materials, their teacher had given them the following formula:

CO2 + sunshine + water = food

This really made me nuts. When my kids were a little younger, I made it a point to find out just how plants turned sunshine into food. It took some doing, but I finally found a DK book that spelled out the relevant chemical formula. Which is this:

6CO₂ + 12H₂O + sunlight ---> 6O₂ + C₆ H₁₂O₆ + 6H₂ O
or...
carbon dioxide + water + sunlight --->
oxygen + carbohydrate + water

Now, she's already given them a chemical name (CO2 -- I asked and one child identified it as carbon dioxide). She could very easily have then given them H2O, water, and then done the math. The carbohydrate, glucose, is a form of sugar, which they would have readily understood -- especially here in upstate NY, where maple sugaring is common!

Actually, I was surprised to see "sunlight" in the actual formula; it provides the energy via chlorophyll, a green pigment that absorbs energy from sunlight. But most amazing of all --

THERE WAS NO MENTION OF CHLOROPHYLL!

(And photosynthesis was hand-written in on the test as an afterthought; I had to help the students out by letting them know that photo means light and synthesis is making something.)

Just to understand, as with most public-school science in my experience, the information the kids had to know was basically all vocabulary. For instance, they had to correctly label the cotyledon of a seed. Now, I doubt there are many adults who can identify cotyledon but not chlorophyll. Really.

Anyway, here, for the record, is my third-grader-friendly, chemistry-literate explanation of how plants make food. I am looking forward to exploring biology again (my plan for next year) in light of my ever-growing comfort with chemistry.

Radioactive Elements

2008-06-11T06:34:00.007-04:00

I became interested in radioactive elements after my brush with thyroid medicine, and I started looking on eBay for a cheap Geiger counter. (My dad, who worked with X-ray machines, brought one home and demonstrated it for us when I was a kid -- another example of how early impressions about science can stick with you.) Before I could finish my research, a friend bought one for us. Turns out, what we actually have is a radiation detector intended for survivors of nuclear war. As one site I read said, if this thing shows a reading, evacuate!

So when I wanted to look at some common household radioactive items, we still didn't have anything to measure them with.

(This didn't work.)

So we found some nice videos on YouTube from people who did have real Geiger counters.

Among the radioactive items people collect or have about are:

smoke detectors (Americium)
salt substitute (potassium isotope)
Fiestaware dishes (the famous orange-y red made with uranium)
gas lantern mantles (a favorite of The Radioactive Boyscout)
old luminous watches (radium)

But here in Saratoga Springs, NY, we have one source of radioactivity that is less common: mineral water.

Back in the 1800s, Saratoga was known for its horse racing, its casinos, and its spas. Its many springs, the result of a geological fault which runs right through the center of the city (it's a low point known until recently as "The Gut", but now the source of trendy new restaurants). Apparently radioactivity is one requirement for "really good" mineral water.

The radioactivity comes from radon gas -- the same stuff that accumulates in basements, a by-product of the decay of uranium -- dissolving in the water underground. Once in the air, the radioactivity dissipates quickly, with a half-life of about four days.

Nevertheless, for the sake of science, we took a walk over to the Saratoga Spa State Park and collected a few bottles from the Polaris spring, one that is known to be radioactive. We also took a sip (it's carbonated but pretty sulfurous, so you wouldn't want to drink it regularly anyhow). So far, no one is glowing in the dark.

The radiation detector wasn't a total loss: it came with a really enlightening manual about radiation safety, for perusal in your fallout shelter. This article from the World Nuclear Association is also basic enough for kids. You'll also find all kinds of fascinating information about radiation at Theodore Gray's Periodic Table.

I'm still planning to get a working Geiger Counter, and maybe a few odds and ends from United Nuclear.

A word from our sponsor

2008-06-05T21:00:00.003-04:00

A new chemistry post should be up this weekend, but in the meantime I'd just like to mention that I've just published my first book AROUND THE WORLD CRAFTS: Great Activities for Kids who Like History, Math, Art, Science and More!

The book is a collection of my Hands-on Learning columns from Home Education Magazine.

Enjoy!

Shrinky Dink polymers

2008-05-20T17:11:00.012-04:00

I pulled out some sheets of shrink film lying around in my art cabinet so we could play with polymers. Polymers are long chains of molecules that can be manipulated in different ways. Shrinky Dink and similar thermoplastics are stretched using heat. When you re-heat them, they revert to their original shape. Here's a handout for kids from the American Chemical Society on making your own shrink film from recycled clamshell containers from the bakery or salad bar. Look for the #6 recycling symbol (other plastics will react in different ways in heat -- including by giving off toxic fumes). Number 6 is for polystyrene, the same stuff that Styrofoam is made out of. You obviously want the hard, thin, clear plastic, not the expanded puffy stuff.

It'd been a while since I played around with these, and I forgot that you have to let them curl up and then uncurl before removing them from the oven.

We popped them back in the oven and they straightened themselves out, with a little help where they had stuck together. Be careful fiddling around with them: when they're soft enough to unbend, they're still pretty hot.

Here's what the kids made:

Shrinkage: 60% (after baking twice)

Shrinkage: 50%

(By the way, it was a great day to be baking things, a brisk 50-something. In May. Helped me hold out against the urge to turn the heat on.)

Extra Oxygen

2008-05-16T09:08:00.005-04:00

Lesson: The enzyme catalase splits hydrogen peroxide into water and oxygen.
What Happened: Adding yeast to hydrogen peroxide caused it to foam up with oxygen bubbles, which re-ignited an extinguished splint.

Science educator Robert Krampf has a collection of home science videos -- many but not all about chemistry -- on his website. He recently re-instated his email list, and I decided to try today's Experiment of the Day with some friends who are visiting. You can see Krampf explaining the experiment as he performs it on his website, which I have added to the sidebar. Here is an excerpt:

You will need:

a wooden, cooking skewer
a lighter
3% hydrogen peroxide (from the grocery or pharmacy)
a cup or glass
yeast

Pour some hydrogen peroxide into the glass. Sprinkle some of the yeast into the peroxide and give it a stir. Very quickly you will see bubbles rising, producing foam on top of the liquid.

Light the end of the wooden skewer, and let it burn for a moment. Then blow out the flame. If you blow gently on the burning end, you should see a red glow. It is still burning, but not flaming. Carefully bring the glowing end of the skewer up to the larger bubbles in the foam. The skewer should flare up, bursting into flame.

We did not get the dramatic results that he gets in the video, but after a few tries we figured out that you need to let the skewer burn for few minutes to get hot enough to reignite.

Here is an explanation of how our bodies use catalase in the same way:

Hydrogen peroxide is a toxic by-product of respiration.  Organisms that
obtain energy by oxidation of foods must develop mechanisms to limit the
damage it causes.  This is primarily accomplished by a class of enzymes
called catalases, which catalyze the reaction

2 HOOH --> 2 H2O + O2

Surfaces and Density

2008-05-07T18:33:00.000-04:00

This week we did a number of experiments with oil, water, food coloring and various props to explore the property of surfaces. The physical properties like surface tension and solubility are related to the strength of Intermolecular Forces -- the attractive forces between molecules.

Surface Tension Experiments

These came from the website of the Chicago Section of the American Chemical Society

3 bowls or containers with water
liquid soap
pepper
a piece of string
a paper clip
a fork
a needle

Bowl 1:

1. Sprinkle pepper on the surface of cold clean water in a shallow dish. Allow the particles to spread out and cover the surface.

2. Put your finger in the bowl.

3. Put a drop of liquid soap on your finger. Put your finger in the bowl again.

What should happen: Pepper should rush away from your finger in a star pattern.

What did happen: Pepper rushed away from finger in a circle -- still impressive.

Bowl 2:

1. Float a small loop of string in the middle of the surface of water.

2. Put a drop of liquid soap inside the loop.

What should happen: The surface tension inside the loop of string should weaken by the soap but the surface tension outside the string should have pulled the string outward.

What did happen: The string sank before we could try step 2.

Bowl 3:

1. Lower a paper clip and a needle flat onto the water surface using the fork. They should float.

2. If they don't, place a paper towel on the surface of the water, place the objects on the paper, and then remove the paper.

3. Now put a drop of liquid soap on the water surface.

What should happen: As soon as the tension is broken by the soap, these items should sink to the bottom.

This one worked as planned!

Density Column

Joy of Chemistry, page 131

2 clear glasses or plastic cups
Glycerin
Water
Food coloring
Cooking oil
Liquid soap
Plastic spoon

1. Pour about an inch of water into the cup.

2. Add food coloring to the water.

3. Pour about an inch of glycerin into the second cup.

4. Gently add colored water.

5. Add oil until you get three layers.

6. Stir. Allow to settle.The water will mix with the glycerin, but the oil will separate back out.

7. Add a layer of liquid soap.

8. Stir gently. The oil will mix with the glycerin.

What's Happening: Different liquids have different densities, and according to the density, the liquids will settle in a certain order when mixed. Oil is less dense than water and therefore will settle on top of water.

(NOTE: Glycerin--C₃H₅(OH)₃, which can be bought in drugstores -- can be added to dish soap to make long-lasting bubble solution. Bubbles eventually burst once the layer of water evaporates, but glycerin forms weak hydrogen bonds with water, delaying evaporation. )

Lava Lamp

(Sorry that it's sideways. When I figure out how to fix it, I will repost it!)

Tall narrow jar
Water
Food coloring
Vegetable oil
Salt

Directions:

1. Fill the cylinder with water.

2. Add the food coloring. Do not let the water become too dark.

3. Slowly pour oil into the cylinder. It should make a thick layer on top of the water.

4. Slowly sprinkle the salt into the cylinder on top of the oil. The salt coats the oil and causes it to fall to the bottom of the graduated cylinder in globs. The oil will gradually return to the top of the graduated cylinder.

What happened:

Vegetable oil is less dense than water. When the salt is added, it sticks to the oil and drags it down. Once at the bottom, the water dissolves the salt and the oil floats back up.

The reason the oil doesn't dissolve into the water happens because of its difference in polarity. Water and salt are both polar. Oil is non-polar. Only polar substances will dissolve polar substances. A non-polar substance will not dissolve in a polar substance. This is the rule of "like dissolves like."

Testing week

2008-04-29T21:22:00.003-04:00

Home Chemistry experiments are on hiatus this week for state-mandated standardized testing for the kids (and so Mom can catch up on writing deadlines). Posts will resume soon! In the meantime, a joke:

Q: Why are chemists great at solving problems?
A: They have all the solutions.

More chemistry jokes (and explanations) here.

Paper Mache and Gluten

2008-04-21T23:06:00.003-04:00

Mixed up some flour paste for a paper mache project I'm going to be working on this week. According to The Papier Mache Resource, it's the gluten in the flour that makes it sticky. The Exploratorium has an animation that shows how the protein molecules line up to form a gooey elastic mess. My batch developed a sticky skin that I skimmed off -- hopefully the remaining liquid is goopy enough!

Description of image, borrowed from ChemConnections:

Molecular model of the spiral structure formed by the HMW subunits of glutenin.

Endothermic Reactions

2008-04-16T21:38:00.019-04:00

As a continuation of our foray into heat-producing (exothermic) chemistry, we mixed up some solutions that became colder (endothermic). Endothermic reactions involve electrons jumping to higher orbitals, which requires an input of energy. The atoms absorb energy in the form of heat from the surrounding environment, thereby lowering the temperature. Unfortunately notetaking that day was not optimal, but here is an idea of what we did:

Since we didn't have the recommended styrofoam cups for mixing our solutions -- which I assume were supposed to provide some insulation between the solution and the air temperature around it -- we used doubled-up paper coffee cups (just like my favorite coffee shop). We used a meat thermometer I found around the house (purchased for a greenhouse gas experiment I never got around to doing) and a 99 cent house thermometer I picked up at Wal-Mart. All the experiments dropped a few degrees almost immediately, going from a water temperature of about 60 degrees Fahrenheit (sorry, we're working in an American kitchen, not a lab with metric measurements) to about 55 or 50 in a minute or so. You could just barely feel the difference by putting your finger in it (we totally forgot gloves and eye protection for this one), so the thermometer is a must.

First was potassium chloride, found in salt substitute. We mixed in an unmeasured proportion with tap water.

Next, we cut open a cold pack from an old first-aid kit. The cold-pack consisted of two compartments, one containing urea (or crystalized peepee, used in cigarettes, pretzels, bath oils, cloud seeding, and tooth whitening -- although I think they make it artificially!) and the other water. You're supposed to squeeze the water portion, which I guess forces it into the other portion. We just poured the crystals into a cup and added water.

The third mixture was baking soda and citric acid. We only had a small jar (scavenged from some old science kit, I believe) so we put about half a teaspoon in the cup and mixed with a little water. Then we poured in some baking soda. It fizzed up nicely, of course, as it would with vinegar. According to about.com, the reaction was:
H₃C₆H₅O₇(aq) + 3 NaHCO₃(s) --> 3 CO₂(g) + 3 H₂O(l) + NaC₆H₅O₇(aq)

Finally, we mixed some calcium chloride -- the kind of road salt used to melt icy sidewalks -- with water. Surprise! This one turned out to be exothermic. The temperature went up to 78 degrees. Pretty neat.

Your name in elements

2008-04-14T22:05:00.005-04:00

Theodore Gray, creator of the lovely Periodic Table Table, emailed me today with news of his element banners. The idea is to spell words or phrases using only the one- or two-letter element abbreviations, then illustrate the spelling with photos from the poster of his table. The banners are pricey, but you can have fun just seeing how your name looks in elements. See a different version of my name here.

Crossposted to GeekDad.

Elementeo

2008-04-13T21:44:00.006-04:00

Elementeo is a strategic battle game where you use your elements across the battlefield in reducing opponent’s electrons to zero. You do that by harnessing the strength and moving properties of the elements and compounds, and by using their reactionary powers. For example, Oxygen can rust any neighboring metal or Copper Conductor can shock any metals and send them back to the deck. According to the game's inventor, Anshul Samar, an eighth grader:

Each card has fantasy, education, and fun all mixed in. From the educational side, one card contains the atomic number, elements family, atomic mass, state at room temperature, oxidation state, and symbol of one element. Compound cards include formulas and how dangerous or flammable the compound is in our world. Alchemy cards go over a wide range of chemistry and physics subjects.

The game should be available the end of this month at the Elementeo website.

Thanks to my friends at Geekdad!

Nitric Acid and Ethanol

2008-04-10T22:12:00.001-04:00

Tonight we saw an episode of "The Simpsons" where Bart lets loose a python in the school chemistry lab. A flask full of ethanol is knocked over, followed by a flask full of nitric acid (labeled "Do Not Mix with Ethanol"). The combination forms a toxic gas.

The Simpsons is known for sprinkling math and science references throughout its scripts. (See Paul Halpern's book, right.) That's because many of the show's writers have advanced degrees in the subjects, including writer Bill Odenkirk, who has a Ph.D. in chemistry and George Meyers, who holds a degree in biochemistry from Harvard. In this episode, first aired last May, a math textbook gets shot and "bleeds" equations, and physicist Stephen Hawking makes an appearance in a flying wheelchair.

However, it turns out that the writers got this one wrong, as noted in this entry on tv.com:

When nitric acid & ethanol are mixed in this episode it produces a toxic gas. In fact, mixing these two chemicals will make a very explosive mixture, not a toxic gas.

Or if you don't care to rely on chemistry facts from a TV website, here's a more reputable source.

Aspirin Lab

2008-04-06T10:50:00.027-04:00

Lesson: Acid-catalyzed hydrolysis of acetylsalicylic acid to salicylic acid and acetic acid
What Happened: We dissolved the active ingredient of aspirin in water, separated it from the binder, then purified the drug using sulfuric acid as a catalyst.

The World of Chemistry video series, which you can watch online at Annenberg Media, has been serving as our spine lately. We were up to the episode on catalysts this week, so I found a demonstration from The Joy of Chemistry (actually from the chapter on organic chemistry) which used dilute sulfuric acid (sold as aquarium pH lowering solution) as a catalyst to purify aspirin. FYI, another example of a catalyst at work were the pineapple enzymes we used to dissolve Jello.

According to Wikipedia, the end product of this demonstration, salicylic acid, is what aspirin metabolizes into in the liver. Its name comes from the Latin word for the willow tree, Salix, from whose bark it can be obtained. Interestingly, it can also be derived from methyl salicylate (oil of wintergreen). In 1897, Felix Hoffmann, a chemist at Friedrich Bayer & Co., obtained acetylsalicylic acid by a reaction of salicylic acid and acetic anhydride; this is the basis for Bayer's claims to the discovery of aspirin.

Materials:

Safety glasses
Rubber gloves
10-15 aspirin (plain or buffered)
½ cup (120 ml) rubbing alcohol (70% isopropyl)
2-4 large glass containers (we used a Pyrex bowl and old honey jars and canning jars)
Coffee filters and rubber bands
Sturdy plastic spoon
Aquarium lowering solution (dilute sulfuric acid)
Pipette or straw

Place aspirin in glass.
Pour in alcohol, a little more than needed to cover the aspirin.
Heat the glass in the microwave on 50% power for 30 seconds until warm but not boiling. The acetylsalicyclic acid will dissolve in the alcohol, leaving the starch binder.
Gently crush remaining residue with spoon to extract as much acid as possible. Let sit 15-30 minutes.

Take coffee filter and spread it over top of second glass. Push it down slightly so it resembles a funnel. Secure with rubber band.
Carefully pour the solution through the filter. The liquid that drips through is called the “mother liquor.” The acetylsalicylic acid has dissolved in the water. What's left on the filter is the starch binder that holds the drug in the pill shape.

Wearing gloves, dispose of coffee filter. Don’t touch the wet part.
Run a small stream of cold tap water. Take the glass with the mother liquor and add water until it is about ¾ full. Small white flakes of acid should begin falling out of solution. Let sit for a couple hours.

Set up another filter on another glass. Pour mixture through filter to separate out the crystals. Filter 2-3 times if needed, letting solution sit for 1-2 hours in between.
Allow to dry overnight, away from breezes. The crystals will become fluffy.
Take ¼ of wet or dry crystals and put into glass. Add aquarium solution dropwise with a pipette or straw until the entire sample is completely covered. The sulfuric acid is the catalyst and remains at the end, so be careful with the liquid.
Heat the mixture in the microwave for no more than 15 seconds at 50% power. It may start to steam immediately.
Remove glass. You should smell vinegar (acetic acid) evaporating. If not, wave your hand over the glass to waft the fumes towards your nose. The sludge that remains is salicylic acid.
Dispose of solids in the trash and liquids in the toilet.

NOTES: We ended up doing the demonstration twice -- although, as it turned out, we probably didn't need to -- because the shopping list at the beginning of the book didn't specify that the alcohol needed was 70% concentration. I found an old bottle of the right concentration, and we did everything over. However, we discovered that letting the first solution sit and filtering it several more times yielded enough crystals to do the demonstration.

In the end, we had twice as much acetylsalicylic acid as we needed. We probably used too much in the final step (as well as too much sulfuric acid, which I tried to pour slowly out of the bottle instead of using a pipette) because when we put it in the microwave, it immediately started steaming! I turned it off a few seconds short of 15 and the vinegar smell was overwhelming.

April Fool's!

2008-04-01T22:04:00.000-04:00

The Periodic Table of Rejected Elements -- containing such families as the Dingy Gases of L (Linoleum) and Vi (Visine) -- was created by Michael Gerber and Jonathan Schwarz for the Atlantic Monthly.

Here's another cute variation: The Periodic Table of Hardware.

B is for Bolt, Al is for Aligator Clip, Kr is for Key Ring. From artist Jim Rosenau's site This into That.

I did a search for any other chemistry-related April Fools items, but all I could find were teachers who informed their class there would be a major quiz. Since I don't do grades, I'll give you a pass on that one!

Hand Warmers

2008-03-26T22:17:00.009-04:00

(Click for larger image)

Lesson: Exothermic reactions produce heat
What Happened: Iron powder began oxidizing (rusting) when exposed to the air, becoming hot

Bought these packets at Wal-Mart a few months ago and figured it was time to open one up and see what would happen. The "all-natural" ingredients seemed pretty safe to mess around with.

As soon as I poured the powder into the mason jar, it started to heat up. I don't know how hot it got (Note to self: Get thermometer!) but I suspect it was hotter than the temperatures listed above, because it didn't last as long. Probably because it was exposed to more air than if I had left it in the air-permeable packet. It may have dried out quicker, too.

Although you can't see it in the picture at the top, there was smoke coming out of the jar. We also tried mixing some with a little more water to see what happened. The heating process stopped. However, when I dipped a magnet into the resulting goop it did act a little like ferrofluid.

What's going on (from Camping Survival):

The heating process takes place in this fashion:
The iron in the pouch, when exposed to oxygen, oxidizes and therefore produces heat (aka, "Air Activated").
When iron oxidizes it produces iron oxide, more commonly referred to as rust.
The salt acts as a catalyst.
The carbon [activated charcoal] helps disperse the heat.
The vermiculite [the shiny mica-like specks] acts as an insulator for the purpose of retaining the heat and the cellulose is added as a filler.
All of these ingredients are surrounded by a polypropylene bag.
Polypropylene allows air to permeate the ingredients while holding in moisture.

And the chemical equation (from Curriki, which tells you how to mix up your own):

Hand warmers work because of a rusting process. The rusting is a redox reaction and the equation is as follows: 4Fe(s) + 3O₂(g) -> 2Fe₂O₃(s) .

Peeps Chemistry

2008-03-23T19:54:00.006-04:00

There is a long and glorious tradition of torturing leftover Easter candy. At the site Peep Research, the fear response of a Marshmallow Peep is measured through exposure to heat in a microwave. But many of the more sophisticated Peeps experiments can probably not be done at home. While you can replicate the vacuum experiment above (by Seaford, NY chemistry teacher Edward Kent, who has many other interesting demonstration videos on his website) by using an ordinary Kitchen Vacuum Packer as shown on the Steve Spangler website, the explosive liquid oxygen video should be only be done under laboratory conditions.

More Peepy links at Peep-O-Rama including Martha Stewart's recipe for fresh, homemade Peeps (sort of an oxymoron). Also solubility tests by a stuffed chemistry mascot mole.

Oh, and here's the chemistry explanation, from the Exploratorium's Science of Cooking website:

Marshmallows are mostly sugar and water wrapped around a bunch of air bubbles. When you cook marshmallows in your microwave oven, several things happen at once. The microwave makes the water molecules vibrate very quickly—which makes the water heat up. The hot water warms the sugar, which softens a little. The hot water also warms the air bubbles.

When you warm air in a closed container, the gas molecules move around faster and push harder against the walls of the container. As the air in the bubbles warms up, the air molecules bounce around faster and faster and push harder against the bubble walls. Since the sugar walls are warm and soft, the bubbles expand, and the marshmallow puffs up. If it puffs up too much, some air bubbles burst, and the marshmallow deflates like a popped balloon.

When you take the marshmallow out of the microwave and it cools off, the bubbles shrink and the sugar hardens again. When the microwave marshmallow cools, it’s dry and crunchy. We think that’s because some of the water in the marshmallow evaporates when the marshmallow is hot. If you cook your marshmallow for too long, it turns brown or black inside. That happens when the sugar gets so hot that it starts to burn [known as caramelizing].

Baking soda vs. baking powder

2008-03-22T16:32:00.004-04:00

Apricot, Poppy, and Chocolate Kiss filled Hamantaschen

We made Hamantaschen cookies for Purim and the question came up about the difference between baking soda and baking powder. We have done the baking soda and vinegar thing many times, so we already know that mixing sodium bicarbonate with an acid releases carbon dioxide. When you bake, those little bubbles of CO2 make the bread puff up. The acid needed to start the reaction in a batter can come from yogurt, buttermilk, lemon juice, or even molasses or honey.

Baking powder is baking soda with the acid already mixed in, in the form of cream of tartar. When moistened, powdered acid combines with the baking soda and produces the requisite bubbles. Some baking powder is "double acting," meaning it releases most of the bubbles when heated, so that the leavening action doesn't expend itself while the dough is waiting on the counter to bake.

Baking powder and water fizzing

There are many explanations on the web about this topic, but I like this one from something called Wally's Food Company. Scroll down to read the chemical explanation of why baking soda absorbs odors in the refrigerator.

Tartaric acid

Breaking Molecular Bonds - Jello and Pineapple

2008-03-13T23:39:00.012-04:00

Lesson: Breaking molecular bonds in protein using enzymes

What Happened: We disintegrated Jello using pineapples

(With help from Anthony)

The ingredients

Before we added the pineapple

The Jello started to melt after a minute

The Jello was half dissolved by now

Ewwwwwwwwwwwwwww

The Jello is almost fully dissolved by now

It's fully dissolved now

Warning: Do not add pineapple

Why did it do that?

(From Chempedia)

Jell-O gelatin was first patented in 1845 by Peter Cooper of Cooper Union.

Gelatin is a processed version of the protein collagen, a simple protein that makes up one-third of all proteins in the human body. The main source of the collagen that is used in Jell-O comes from hooves, bones, connective tissue found on cows, horses and pigs. Along with collagen, Jell-O consists of water, food coloring, sugar, and artificial flavors. Collagen is found in all living animals. This protein is what gives body parts strength, flexibility, and protection. There are five major categories of collagen that range from the fibers in your eyes to the structure of placentas. To harvest the collagen needed for gelatin the Jell-O Corporation turns to natural sources found in cows, horses, and pigs. The animals' body part's which were previously mention are ground up to expose the proteins within. After they are ground up the bio matter is then treated with a strong acid or base, which breaks down the cellular structures of the collagen to release the proteins from connective tissue. After the proteins become separated from the tissues the bio-mass is then discarded. Then, the mixture created from the released proteins (collagen proteins, which are the basis of Jell-O) and the strong acid or base is then boiled.

(From General Chemistry Online)
Pineapple contains a plant enzyme called bromelain that breaks down proteins. Bromelain is used in many meat tenderizers for this purpose (and that's why cooking ham with pineapple makes it tender). JellO packages warn you not to put pineapple chunks into the gelatin. Jello is a protein mesh with trapped pockets of liquid; the bromelain cuts the protein chains and keeps the gelatin from jelling properly. Why do pineapples produce an enzyme that tenderizes meat? It's a defense mechanism. The sap of the pineapple plant contains much higher concentrations of bromelain and can cause severe pain if eaten.

Other uses for bromelain:

(From Wikipedia)
Bromelain can be used in a vast array of medical conditions. It was first introduced in this area in 1957, and works by blocking some proinflammatory metabolites that accelerate and worsen the inflammatory process. It is an anti-inflammatory agent, and so can be used for sports injury, trauma, arthritis, and other kinds of swelling. Its main uses are treatment of athletic injuries, digestive problems, phlebitis, sinusitis, and aiding healing after surgery.

Light and Chemistry - Triboluminesence

2008-03-10T21:35:00.009-04:00

Lesson: Breaking molecular bonds can release energy in the form of light
What Happened: We crunched Altoids in a dark room and saw blue-white sparks.

Traditionally, this demonstration is done with Wint-O-Green Lifesavers -- but the package I found at the supermarket listed only artificial ingredients. What makes the candy spark visible is the fluorescent property of wintergreen's aromatic essence, methyl salicylate. So we tried Altoids and Canada Mints. At night, we went into the bathroom (so we could see ourselves in the mirror), turned off the lights and waited a few minutes for our eyes to adjust to the dark. The Altoids worked well. The Canada Mints are slightly more chewy and hence, did not crunch well.

The website How Stuff Works explains the process like this:

Triboluminescence occurs when molecules, in this case crystalline sugars, are crushed, forcing some electrons out of their atomic fields. These free electrons bump into nitrogen molecules in the air. When they collide, the electrons impart energy to the nitrogen molecules, causing them to vibrate. In this excited state, and in order to get rid of the excess energy, these nitrogen molecules emit light -- mostly ultraviolet (nonvisible) light, but they do emit a small amount of visible light as well. This is why all hard, sugary candies will produce a faint glow when cracked.

Although it was fun to watch the bright flashes of light in our mouths, we had to stop after a few candies because the sharp mintiness got to us.

A photo of the flash, from Wayne's This and That:

Interestingly, as I learned from Wikipedia, methyl salicylate, or C₆H₄(HO)COOCH_3,is what gives Ben-Gay its minty heat. It can cause poisoning and even death when eaten or applied to the skin in large amounts.Curiously strong, indeed.

The Problem with Homeschool Science Resources

2008-03-09T10:59:00.005-04:00

Way back in November, I got a comment about finding hard-to-locate chemicals from Ruth in NC, whose own blog is Traveling Jews, suggesting that I try a company called Home Science Tools. I checked out their website, and was pretty impressed. In fact, we got a microscope from them for the holidays.

But I couldn't bring myself to add them to the sidebar list of suppliers, because of books like the one shown here -- biology curriculum from places like Bob Jones and "God's Design" that teach creation "along with evolution." (If you think this issue just affects homeschoolers, though, see my related blog posts here and here.)

Interestingly, parents whose children have used these texts say their kids score very well on standardized science entry exams for college. (I wonder whether that's a comment on what the tests include...)

I realize that so far, despite the number of resources I've turned up, our chemistry studies this year have stayed on a pretty superficial level. There are lots of homeschoolers who are going through much more rigorous courses than I am. So, what programs do your kids use? How have they worked out?

More Light and Chemistry-A Homemade Spectroscope

2008-03-05T12:26:00.006-05:00

In Oliver Sacks' book Uncle Tungsten: Memories of a Chemical Boyhood, he describes walking around with a pocket spectroscope, observing the bright and dark lines in the spectra of different types of light sources.

Instead of buying the lovely model above from Educational Innovations, however, we followed Simon Quellen Field's directions for a home-made spectroscope on his website scitoys.com. (It's also in his book,Gonzo Gizmos: Projects & Devices to Channel Your Inner Geek.)

Here's Field's explanation of what's going on:

A spectroscope is a device that lets us find out what things are made of. It works by taking light and splitting it up into its component colors. Different elements make different colors when they glow. We can make objects and gasses glow by heating them up in a flame, or by passing electricity through them. The spectroscope spreads out the colors of the light, and we can identify the elements by the bright lines we see in the spectroscope.

We pretty much followed Field's directions, except for using duct tape instead of aluminum tape.

The razor blade slit, which is where the light comes in, was also finished off with duct tape. I forgot to take a picture of the placement of the DVD; we measured the distance from the slit to the end of the box and marked a line for the left edge of the disc. (See Field's directions to figure out what I'm talking about.)

We used it on incandescent and fluorescent bulbs and sunlight, and it seems to work pretty well. I noticed that along with the spectrum, you get a pinhole camera effect. We'll have to find some other light sources to test it out on.

Black Light

2008-03-01T20:32:00.017-05:00

From About.com's Chemistry Page

There are a lot of everyday materials that fluoresce, or glow, when placed under a black light. A black light gives off highly energetic ultraviolet light. You can't see this part of the spectrum, which is how 'black lights' got their name. Fluorescent substances absorb the ultraviolet light and then re-emit it almost instantaneously. Some energy gets lost in the process, so the emitted light has a longer wavelength than the absorbed radiation, which makes this light visible and causes the material to appear to 'glow'. Fluorescent molecules tend to have rigid structures and delocalized electrons.

(The black light fluorescent bulb, with holder, was $10 at Wal-Mart. It can be plugged in and moved around wherever needed. We also have an incandescent black light bulb, but it doesn't work very well, and gets very hot.)

What we got to glow:

White Paper

White paper is treated with fluorescent compounds to help it appear brighter and therefore whiter. Sometimes forgery of historical documents can be detected by placing them under a black light to see whether or not they fluoresce. White paper made post-1950 contains fluorescent chemicals while older paper doesn't.

Tonic Water

The bitter flavoring of tonic water is due to the presence of quinine, which glows blue-white when placed under a black light.

Laundry Detergent

Some of the whiteners in detergent work by making your clothing a bit fluorescent. Even though clothing is rinsed after washing, residues on white clothing cause it to glow bluish-white under a black light. Blueing agents and softening agents often contain fluorescent dyes, too. The presence of these molecules sometimes causes white clothing to appear blue in photographs.

What we didn't get to glow:

Vitamins

Vitamin A and the B vitamins thiamine, niacin, and riboflavin are strongly fluorescent. Try crushing a vitamin B-12 tablet and dissolving it in vinegar. The solution will glow bright yellow under under a black light.

Chlorophyll

Chlorophyll makes plants green, but it fluoresces a blood red color. Grind some spinach or swiss chard in a small amount of alcohol (e.g., vodka or everclear) and pour it through a coffee filter to get chlorophyll extract (you keep the part that stays on the filter, not the liquid). You can see the red glow using a black light or even a strong fluorescent bulb, such as an overhead projector lamp, which (you guessed it) gives off ultraviolet light.

Sodalite

Minerals and gemstones are most commonly made fluorescent or phosphorescent due to the presence of impurities. A sample of sodalite I bought at the New York State Museum back during Chemistry Week in October came with a slip of paper said "many" specimens are fluourescent; ours was not.

(A transparent piece of what I think is agate did glow a nice orange color, but it came out bluish in the photo.)

Might try next time:

Postage stamps
Tooth whiteners
Dollar bills
Petroleum jelly
Highlighters
Solar beads
And making bubble juice out of fluorescent soap!

What glowed that we weren't expecting:

Dandruff!

Fizz, Bubble & Flash

2008-02-24T09:30:00.005-05:00

I reserved this book through my library's website a while back but just took a look at it the other day. At first glance, it looks like a book for younger children (the age range listed on the back is 8 and up). But with its lively, clear explanations of all the elements and families of the periodic table and its nicely-laid-out experiments, including variations on demonstrations I've seen elsewhere plus some that are new to me (such as one that tests zirconium-based underarm anti-perspirant on aluminum foil), I'm thinking of buying a copy to keep around for my own teens. Author Anita Brandolini is a chemistry professor at Ramapo College who tested out the activities on kids at the Liberty Science Center in New Jersey (a museum which my family has enjoyed on trips with the grandparents). My only beef: in general the illustrations are cute, but the drawings of molecules don't successfully convey the idea of their structure in three-dimensional space.

Comic Book Elements

2008-02-20T21:00:00.007-05:00

"OK, 103 -- Now you're going to turn him into pure copper!"

Coughs, colds and catching up have kept us from doing more experiments. Hopefully we'll get back to it soon.

In the meantime, while searching for info on Ferrofluid and Magnetic Slime, I came across this nifty site. The Periodic Table of Comic Books links each element to its appearance on the printed page. From the University of Kentucky Department of Chemistry!

Access to Chemistry at Oxford

2008-02-16T09:26:00.005-05:00

Oxford University in England has joined the list of colleges offering FREE online courses to the public. Their Access to Chemistry website "provides an excellent resource for prospective applicants to learn more about Chemistry at Oxford from anywhere in the world."

When you click on Pre-University Course, you can page through teaching material based on the book "Chemistry, Matter and the Universe" by Richard E. Dickerson and Irving Geis -- complete with helpful animated illustrations. Here's the introduction:

Many reasons can be given for studying chemistry, ranging from, "It is an intellectual adventure," to "I can make a good living at it," or even "It is required for graduation."

But the most valid response is simple. Chemistry is the study of how matter behaves. We have only one world in which to live. If we want to know how we can change it and what we cannot alter, or even simply to appreciate what we already have, then we must know how it works.

Chemistry is the subject that tells us this. Physics may teach us fundamental facts about elementary particles, matter, and energy, but it stops short of drawing conclusions about how the different kinds of matter around us change and react. Biology describes the large-scale behavior of organisms, which at their core are elaborate chemical systems. Some of the most fruitful advances in biology in the past two decades have come from a thoroughly chemical approach. If we can expand the concept of chemistry beyond our present limited and inadequate knowledge, then biology fundamentally is the highest form of applied chemistry. If chemistry is the study of how matter behaves, we must not forget that we, ourselves, are an integral part of this material world.

This is all part of Oxford's Virtual Chemistry Virtual Laboratory, which includes a 3DChem (a molecule of the month website), LiveChem (a library of nearly 300 videos), and a Webcast Lecture Series of courses such as Dr. Hugh Cartwright's Entertaining Chemistry. Looks to be an excellent resource!

Happy Valentine's Day!

2008-02-14T09:52:00.007-05:00

Do these hearts look strangely familiar to you?

H2O2

Hydrogen Peroxide

Ozone

Oxygen

Courtesy of Muse, the world's best magazine for tweens!

February's cover features "Oxygen: A Love Story" -- an excerpt from Gabrielle Walker's new book, An Ocean of Air: Why the Wind Blows and Other Mysteries of the Atmosphere, which tells how Earth's atmosphere developed.

I just loved the way it looked!

Precipitation

2008-02-12T20:41:00.002-05:00

No, it's not raining or snowing (at the moment). Last week we did two (of four) small demonstrations from The Joy of Chemistry to illustrate how different conditions affect whether a solid will go into a liquid in solution or fall back (precipitate) out. Here, in my non-official lab report style, are our results:

Demo 1: Baking Soda
Effect of Temperature and Amount

Materials

Baking soda
Water
Glass measuring cup
Plastic spoon

Directions

1. Add a pinch of baking soda to 2 cups of water. Stir to dissolve.
2. Keep adding pinches (about 10-15) until solution starts to become cloudy and baking soda fall to the bottom.
3. Microwave glass for 30 seconds, until warm.
4. Is solution clear? Does precipitate dissolve with stirring?

Observations

It took 45 "pinches" of baking soda to get enough precipitate on the bottom of the cup to notice. The water was only barely cloudy. Measuring out the baking soda in 1/4 or 1/2 teaspoon amounts -- or using less water -- would make the process go faster.

Heating the cup in the microwave even a small amount did allow all the baking soda to go into solution.

As a demo for kids, less than impressive.

Demo 2: Chalk in Water and Vinegar

Effect of Condition of Salt and of Solution

Materials

Prang* white chalk
4 plastic cups
Water
Vinegar

NOTE: Prang brand chalk worked great! (Not like our first attempts with other chalk.) Still haven't found it for sale locally, though -- I found some in a school I visited and borrowed a piece.

Directions

1. Break chalk into 4 pieces.
2. Crush 2 teaspoons of chalk.
3. Fill 2 drinking cups with 1 cup of water. Fill other 2 cups with 1 cup of vinegar.
4. Place 1 whole piece in first cup of water. What happens?
5. Place 1 teaspoon crushed chalk in water and observe. Stir. What happens?
6. Repeat with chalk and vinegar. What happens?

Observations

Whole piece in water: Nothing
Powdered chalk in water: Water got very cloudy
Whole piece in vinegar: Chunks of chalk broke off in layers and floated to the top!
Powdered chalk in vinegar: First it foamed up. After a few minutes, chunks started bobbing up and down!

(Took some lovely video of the bobbing effect which came out sideways. When I can convert the MOV file to AVI so I can rotate it in Windows Movie Maker -- or get more chalk and re-shoot it -- I will post it!)

New and Improved About.com Chemistry Page

2008-02-06T15:46:00.001-05:00

Today I'm making up a worksheet of experiments to do later in the week about solutions and precipitates, based on our "spine," The Joy of Chemistry. While I find the book helpful in organizing my lessons (and, of course, providing all my information), it hasn't worked for us as a read-aloud. So what I do is go through the chapter I want to cover, find the demonstrations that I think we can do (based on availability of materials and risk level) and type them up. Surprisingly, despite the analogy the authors make to "The Joy of Cooking," the "recipes" in their book are integrated right into the text. So unless you're reading it surrounded by your fully-appointed and ready-to-use laboratory, it's a little hard to do the demonstrations just using the book. To make them usable for us, I've been putting them into recipe form -- Explanation, List of Equipment and Ingredients, Directions. I told both co-author Monty Fetterolf and his publisher's PR person that if they don't come out with a new edition, I'm going to write my own companion volume when I'm done!

One other thing I've been doing is finding similar, related experiments to add to, modify or replace some of the demonstrations in the book that I feel could use improvement (or just can't resist tinkering with). My main source for this information has been Anne Helmenstine's Chemistry section at About.com. I just scooted over there to see what she had on our upcoming projects and saw the site has gotten a makeover. It's cleaner looking, and the ads have been toned way down, making it easier to find what you want. The current lead story is about making a "Do It Yourself Chemistry Lab." One interesting question discussed: "Is It Safe to Use Kitchen Glassware for Chemistry?" Helmestine writes:

I remember a chemistry experiment in analytical chemistry class where we were asked to take a piece of glassware from the storeroom, get it as clean as we could, and then the instructor rinsed it with acid and water and showed us the spectrum of the stuff that was still on the glass. As you would imagine, there were heavy metals and some dangerous organics. He was trying to illustrate that even 'clean' glassware isn't inert and can mess up an analysis, but it also went a long way to explaining why we shouldn't make coffee in the lab. Using dishes for chemistry projects isn't the same thing, but it may not be safe.

Her conclusion? Yes and no. "If I make slime or a smoke bomb I'll use dishes, but I'll be careful to rinse them immediately so that no one accidentally eats borax or saltpeter ... but there are exceptions. For example, I wouldn't make green fire in cookware. "

I know a certain 12-year-old that will appreciate my saving those particular links.

Update: Anne Helmenstine left a nice little comment to this post. And I couldn't asking why the little white dish in the green fire photo above looked so much like a Corningware ramekin. Her reply:

Um... (confession time)... that's because it is a Corning ramekin. I think what I said was I wouldn't use ceramic cookware, not that I didn't, lol. When I tried that project, I did not expect the methanol in the Heet to burn quite that hot. I'm surprised the ramekin didn't shatter. For future tests, I used a stainless steel mixing bowl.

Just so you know.

Kitchen Chemistry for (Big) Kids

2008-01-29T20:01:00.000-05:00

Guacamole, Death by Chocolate Cookies, Scones and Tea ... I can't wait to try some of the recipes, I mean experiments, in the Kitchen Chemistry online course offered by Dr. Patti Christiethrough MIT's Open Courseware website.

Most Kitchen Chemistry is aimed at little kids. This course has you thinking about the molecular basis for building up resistance to the heat of the jalapeno peppers, how copper helps holds together the molecules that make up meringue, and the scaffolding of dough formation.

And from the look of the photo from their class website, it looks like these college students are having fun!

The book used is considered a classic of cooking AND science: On Food and Cooking: The Science and Lore of the Kitchen. I've just added it to my list.

Penny chemistry - Verdigris and copper plating

2008-01-26T22:02:00.002-05:00

Lesson: Copper plus oxygen creates copper oxide (2Cu+O₂-->2CuO )
What Happened: Changing the chemistry of pennies and nails changed their color

Anthony (perhaps inspired by a discussion of the construction of the Statue of Liberty in history this week) wanted to see if he could make a penny turn green by soaking it in water. I suggested we also try vinegar. Nothing very dramatic happened, so I looked it up and found this great demonstration on About.com's Chemistry page:

First we mixed 1/4 cup vinegar with 1 teaspoon salt.
Next we dipped one dull penny in for 10 seconds, making it half shiny.
Then we dumped about 20 dull pennies in the solution for 5 minutes.
When the pennies were removed, some were rinsed with water, the rest left to dry as is. Within a couple of hours, the vinegary pennies had developed a nice verdigris finish.

But here's the best part. Once we took out the pennies, we put some steel nails (I couldn't quite tell if they were galvanized -- zinc-coated -- or not) in the vinegar. Over the next few hours, the nails got a beautiful copper coating. Here's Anne Marie Helmenstine's explanation of what happened: The pennies react with the salt/vinegar solution, releasing positively charged copper ions. The vinegar also dissolves the iron and oxides on the surface of the steel nail, giving it a negative charge. The positively charged copper ions are more strongly attracted to the nail than the iron ions, so a copper coating forms on the nail.

During the process, the hydrogen ions from the vinegar (acetic acid) and the metal/oxides produced bubbles of hydrogen gas.

Although it took longer than advertised, the end result was impressive. Most impressive was finding a way to do copper plating without using CuSO4 (one of the caustic copper sulfate experiments from Joy of Chemistry that I had been avoiding doing).

Update: Works on paperclips, too!

Here's a site that gives all the chemical equations involved.

Extracting DNA at the Tang

2008-01-25T16:21:00.001-05:00

We had a lovely visit to the Molecules that Matter exhibit at Skidmore College's Tang Museum in Saratoga Springs this week. Ginger Ertz, the museum educator, had a DNA extraction kit from Carolina Biologic Supply she wanted to try with our homeschool group.

First we obtained cheek cells by swishing with a little Gatorade while gently biting the inside of our mouths. Then we spit the solution (all the kids actually abided by the instructions NOT to spit through the air!) into little medicine cups, mixed the Gatorade with some other chemicals in a test tube and took a tour of the exhibit while it sat awhile.

Exhibit curator Ray Giguere, an organic chemistry professor at Skidmore, had agreed to give our group a private tour. After the public tour we attended in the fall, I thought it would be really worthwhile, and it was. He even invited one of the parents to audit classes with her teens. He started at the DNA model, went over the plastics and nylon sections we had seen last time, and managed to squeeze in a little info on the Bucky balls. The models you see above are actually dog toys!

The DNA we extracted was replicated into long gooey strands that resembled jellyfish. We sucked them up into pipettes and put them in tiny vials to wear around our necks. I got a little Gatorade in mine.

You can get DNA kits from many suppliers, or make your own.
Rice University's crimesolving website for kids (see below) has a downloadable family activitity brochure with directions for extracting DNA from strawberries. Or you can use different plant material using these directions from the University of Utah. Try it!

Redox Reactions Part Deux

2008-01-21T11:31:00.001-05:00

Lesson: Fire produces CO2
What Happened: Hydrocarbon + oxygen = carbon dioxide + water + heat

According to The Joy of Chemistry: The Amazing Science of Familiar Things (pages 79-81), combustion chemistry is another redox reaction. In this one, a hydrocarbon (a compound made solely of hydrogen and carbon) mixes with oxygen. The carbon is (literally) oxidized, losing electrons to the oxygen atoms, and the oxygen gains enough electrons to attract the hydrogen into forming H2O. Here is what we did:

Materials

Safety goggles
Rubber gloves
Votive candle
Wooden match
2 small clear glass jars
Water
Fish tank indicator
Piece of white paper
Balloon
Drinking straw
Ice cube

1. Pour 4 teaspoons (20 ml) of water into a glass.
2. Add 2 drops of fish-tank pH indicator.
3. Put the glass and one of the empty glasses on a white piece of paper. The water should look faintly green-blue.
4. Light the candle. Invert the empty glass over it. Allow the flame to burn out.
5. Turn the glass over and IMMEDIATELY pour the water solution into it.
6. QUICKLY cover the glass with your hand. Swirl the solution around to mix with the gases from the flame.
7. Put the glass back on the paper. It should have changed color.
8. To test that CO2 was the cause of the color change, make another indicator solution as before in clean glass. Blow up a balloon and pinch closed. Put a straw into the opening of the balloon so that the gas goes into the solution. It should change color the same way.

We also did the next demonstration, to prove that fire produces H2O (page 80):

Materials

Votive candle
Wooden match
1 small clear glass jar
Ice cube

1. Light the candle. Hold the glass over it. Place an ice cube on top.
2. Water will condense inside the glass.

DNA Analysis for Kids

2008-01-19T17:20:00.000-05:00

We will be visiting the Tang Museum's Molecules That Matter exhibit this week for the second time. This week's program will focus on DNA. In preparation, I'm going to be showing my kids some websites about DNA analysis which I found for a Family Online column on Crime Solving for Kids. We will be extracting our own DNA. Sounds cool...

Redox Reaction Demonstrations

2008-01-17T11:47:00.002-05:00

Lesson: Iron can take the form of two different ions in redox reactions

What Happened: Fe2+ + H₂O₂ → Fe3+ + H2O + O2

Ferrous iron + hydrogen peroxide → ferric iron + water + oxygen

Today we did some experiments from The Joy of Chemistry: The Amazing Science of Familiar Things (Demonstration 3, Stop-and-Go Chemistry, Page 73) which demonstrated reduction/oxidation, or redox, reactions. In reduction, electrons are gained, creating a negative ion. In oxidation, electrons lost (often involving oxygen), creating positive ions.

In preparation for this experiment, we first made up a batch of iron acetate, as instructed in the front of the book. Wearing Playtex gloves, John pinched off about a cubic inch of fine steel wool. We dropped it into a jar with 2 cups of vinegar and left it to soak for 24 hours. You could see bubbles of what the book says is hydrogen coming off the steel wool ball, which first floated on the top, then sank, then floated up again. (I did not try to ignite the hydrogen, although I thought about it.)

Ingredients for Iron Acetate

Then today, we gathered the following:

Safety goggles
Rubber gloves
Plastic bowls
Teaspoon
Iron acetate solution
Household ammonia
Hydrogen peroxide

First we ladled 2 tablespoons (30 ml) iron acetate into the bowl. Then we added 1 teaspoon of ammonia to make it turn red. But we found that the color was hardly noticeable. So we added a total of 5 teaspoons. You can see the difference below:

Left: 1 teaspoon ammonia. Right: 5 teaspoons ammonia

Next we dropped in 1 teaspoon (5 ml) of hydrogen peroxide, to turn the solution green. Just the one teaspoon was enough to make the solution the nice dark color.

Since we had set up two bowls (one for each boy) we were able to compare the color change.

Here is what iron acetate looks like chemically:

Fe₃O(OAc)₆(H₂O)₃]OAc (OAc is CH₃CO₂^-)

Anthony helped me with this post. More redox experiments tomorrow!

Alum Update

2008-01-16T09:30:00.001-05:00

While we're waiting for the lemon battery do-over (and possibly other redox experiments), I thought I'd take another look at what the alum crystals are doing.

John had to stop growing the clear crystal when the string broke before Christmas. Anthony is still growing his green crystal, but it's getting ... kind of mushy. I think it has to do with the new solution we put it in.

We tried to make more "alum juice" by taking all the grains of alum we saved after siphoning off the liquid from time to time. Anthony warmed the juice in the microwave so that the alum would dissolve, but I think he let it get too hot. We left the cup of juice to cool to room temperature and went out for the day. (If we had put the big crystal back in the juice when it was still warm, it would have dissolved, because the warmer liquid could take more alum into solution.)

When we got back we found the big chunks of alum you see here. They're sort of deformed, I believe because they formed too fast for the crystal structure to develop nicely. It's interesting that they kept the green food coloring as well, which the slower growing crystals didn't (once they had dried). We may dissolve them and try again.

Lemon Battery, Take 1

2008-01-11T20:53:00.000-05:00

Lesson: Electrochemical redox reactions

What Happened: Copper ions are reduced by acidic lemon juice as zinc is oxidized into zinc ions, moving toward a more stable state and producing electrical energy.

It's the new year, I've finally gotten a replacement for my dearly departed laptop and managed to wrest it into a configuration that allows me to sign in to my blog, so it's time to post more experiments.

The Lemon Battery is one I've been thinking about doing for years. There are many versions of it -- and many opinions about whether it actually works. Here are some of the different incarnations and explanations:

PBS ZOOM
Energy Quest (from the California Energy Commission)
Hila Road (a science camp in Canada that offers directions, including videos, for many experiments)
Bad Physics (why the textbook lemon battery doesn't work)

As usual, I took bits and pieces and put together a version that looked the easiest for us to do. Last summer I was hoping to work it into an alternative energy class I taught for the day I talked about how electricity works, and so I had bought copper and galvanized (zinc-coated) steel wire. I liked the idea I had seen about putting small lemons into an egg carton to create a bigger battery of cells, thereby upping the voltage and current. We had a bunch of lemons, but they were pretty large, so I had the kids cut them into quarters (per Hila Road's instructions).

We rolled the lemons, without breaking the peels, to release the juice inside, cut up the lemons and put them peel side up in the egg cartons. Then we connected the lemon quarters into groups of four, using a piece of copper and a piece of zinc wire for each lemon cell. At that point we had six batteries of four lemon cells each, which according to Hila should have produced enough voltage and current to light an LED bulb.

At this point any semblance of scientific accuracy breaks down. We never got the LED bulb to light. Ditto for the small watch-battery-powered calculator we tried. We did get readings on our multimeters, but I couldn't tell which was which. (I need to look at the instruction sheet to see which scale goes with what measurement.) And I tried to wire the 6 batteries of 4 cells in parallel, but realized afterward that I just connected the batteries in series, so maybe the amperage wasn't high enough.

The kids wandered away at this point, but I want to try this one again (of course). I may use pennies (most places recommend sanding them a little) and galvanized nails as terminals, and just hooking the wire up between the terminals. And I'll have to look up (or ask my dad) about how to wire the batteries in parallel correctly.

For a look at people who DID make this experiment work, go to the links above. Or for a really ~~amazing feat~~ funny takeoff on this idea, go to GeekDad to see my post about the onion/Gatorade battery.

Draw a Scientist Test

2007-12-31T17:37:00.001-05:00

How do you find out what kids think of scientists? Have them draw a picture!

This week I was working on a story about CSI and how it's changed public perception. For DAs, the so-called "CSI Effect" has been a problem: juries expect to see the full array of high-tech analyses before they'll convict a defendant (whether it's needed to prove their guilt or not).

But for kids, the "CSI Effect" is different. Researchers have found that the typical scientist as drawn by middle school students is no longer a nerdy white guy in a lab coast with thick glasses and wild hair. In other words, they don't look like the fellow below, from today's Albany Times Union:

A Rensselaer Polytechnic Institute scientist has discovered a fact about mosquitoes that may turn the treatment model for malaria upside down.
"The mosquito is as much a victim as we are, but nobody thinks of the mosquito that way," said Robert Lindhardt, a biochemist and acting director of RPI's Center for Biotechnology and Interdisciplinary Studies.

Instead, they draw scientists who are more "realistic," researchers say. Something like the woman below, who plays a forensic scientist on CSI: Miami, as quoted in yesterday's Parade Magazine:

Q Your item on Emily Procter made me wonder: Why do she and the other women on the CSI shows, such as Marg Helgenberger and Melina Kanakaredes, choose to show so much cleavage?
—E.G.J., Lothian, Md.

A “You don’t really think we dress ourselves, do you?” asks Procter. Costume decisions lie with the producers and wardrobe staff, who seem to follow the philosophy “the deeper the cleavage, the higher the ratings.”

An Education Rant

2007-12-28T23:51:00.000-05:00

It was probably ten years ago or more than I attended a workshop given by Charles Scaife, then a professor of chemistry at Union College in Schenectady, NY and his wife Priscilla on doing hands-on science with kids. Talking with Scaife afterwards for a story that ran in one of the local newspapers, I heard how most elementary school teachers have little background in science, and how rarely they feel comfortable teaching it. And that was before George Bush's federal No Child Left Behind school policy put the pressure on teachers to prepare children for high stakes standardized tests in reading and math that leave little room for exploration and wonder. Even after school, homework overload also steals times from kids who might otherwise be messing around with stuff that could lead to scientific insights (but that's another rant). The result Scaife said, was fewer students interested in science in the upper grades, and college freshman who can spit back the right answer without any understanding of the underlying concepts or how to apply them.

I bought Scaife's spiral-bound book of experiments like the ones the couple set out for parents and kids at their workshop to use at home. Although we tried just a few (not always successfully, as seems to be par for the course with use), that evening was definitely the catalyst for this Home Chemistry project we're engaged in this year.

Charles Scaife, whose presentations were the subject of a front-page story in The Wall Street Journal, and subsequent stories in USA Today, the Christian Science Monitor, and Education Week,died in 2003. Priscilla carries on the tradition of introducing the magic of science to children.You can check out the Scaifes' experiments for yourself at the Union College website.

Still growing

2007-12-24T11:59:00.001-05:00

The alum crystals are slowly getting bigger. But a lot of the alum in solution in the cups crystalizes out into separate tiny little crystals. Whenever there are too many little crystals in the cup, we decant the solution into a clean cup. And I put the little crystals into a third cup I started.

At first nothing grew. I figured there wasn't enough alum in the solution. But little by little I added more crystals and let the water in the cup evaporate.

Then the other day, I glanced in the cup and saw these, lying on the bottom:

Without the food coloring, they look like diamonds waiting to be put in rings. So cool! All the crystals are flat on the bottom, though. I tied one on a string to see if it would grow, and if it would even out on the flat side. Updates in a few days.

Christmas Candy Chemistry

2007-12-18T12:24:00.001-05:00

We made molasses popcorn balls for our homeschool bookclub meeting. Making candy involves heating the sugary mixture to different temperatures according to the texture you're looking for -- sticky, stretchy, chewy, hard, etc. We used a candy thermometer I happened to have as well as the "drop some in a cup of cold water" method, until we got the texture we wanted.

The molasses actually came out pretty good (one of the moms couldn't stop eating it; I finished off the leftovers this afternoon). But I had made the popcorn in a big spaghetti pot and didn't take out all the unpopped kernels in the bottom, so they got stuck into the balls as well. I made a note in the recipe for next time.

Here's the recipe (reduced by one-fourth, because of the size of the molasses bottle we used):

Molasses Popcorn Balls

1 1/2 cups popcorn kernels
3/4 cup sugar
1 1/2 tablespoons butter
1 1/2 cups molasses
pinch salt
3/4 teaspoon baking soda
3 cookie trays, lined with waxed paper

Pop corn and turn into bowl. Remove unpopped kernels!

In a medium sized to large pot, boil Molasses, sugar, butter, and salt, stirring occasionally until mixture forms hard ball in cold water.

Remove from heat, add baking soda and mix well. It will froth over.

Pour over popped corn, stirring so that each kernel is coated.

Form into a ball with well buttered hands QUICKLY! Place on waxed paper to cool.

The graphic above illustrating the science behind candy hardening is from The Exploratorium's interesting Science of Cooking webpages.

Big Alum Crystal Update

2007-12-13T17:05:00.001-05:00

After a gravelly start, our alum crystals are growing nicely.

Just leaving the solutions sitting in clean cups for a couple days before we could get back to them allowed some good-sized seed crystals to grow. Each kid picked one and tied it to a string. By day two you could see the crystal bulging around the string, and by today, day three, the crystal had swallowed the string and kept growing around it.

Because the boys put food coloring in their water, the strings can be seen clearly. (The string picked up more of the coloring than the crystal, which shows just the slightest tinge of color.)

Oh, I did end up saving the tiny crystal grains, re-melting them in hot water, and putting a leftover seed crystal into a third cup to see if I could get it growing. But I think I put too much water in for the amount of alum, because the seed just disappeared in the solution. I keep adding more alum as the kids clean out the little grains from the cups (by decanting the solution into a clean cup). Eventually, I figure, it should evaporate enough to become saturated and start to form crystals.

Chemicals for Your Kids' Cold

2007-12-11T18:15:00.001-05:00

From the Washington Post:

With many children's cough syrups being pulled from the market because they don't work, an old folk remedy -- honey -- may work just as well or better, researchers report.

In a study of kids having trouble sleeping because of cough, a research team at Penn State College of Medicine compared the effectiveness of a little bit of buckwheat honey before bedtime versus either no treatment or dextromethorphan (DM), the cough suppressant found in many over-the-counter cold medicines.

"Honey provided the greatest relief of symptoms compared with the other treatments," concluded lead researcher Dr. Ian Paul, Penn State's director of pediatric clinical research.

An FDA advisory board recently recommended that over-the-counter cough and cold medicines not be given to children under 6 years of age because of a lack of effectiveness and potential for side effects.

"With honey, parents now have a safe and effective alternative to use for children over age 1 who have cough and cold symptoms," Paul said.

Paul cautioned that honey should never be given to children younger than 1, because of the rare risk of infantile botulism. In addition, he noted, cough medicines that mention "honey" on the label actually contain artificial honey flavor.

Honey is primarily composed of fructose, glucose and water. It also contains other sugars as well trace enzymes, minerals, vitamins and amino acids.

And what is dextromethorphan (C₁₈H₂₅N O)?

Dextromethorphan (DXM or DM) is an antitussive (cough-suppressant) drug found in many over-the-counter cold and cough medicines. Dextromethorphan has also found other uses in medicine, ranging from pain relief to psychological applications. Pure dextromethorphan occurs as a powder made up of white crystals, but it is generally administered via syrups, tablets, or lozenges manufactured under several different brand names and generic labels.

When taken at doses higher than are medically recommended, dextromethorphan acts as a dissociative hallucinogen. It produces effects similar to those of the controlled substances ketamine and phencyclidine (PCP), which affords it a high potential for abuse.

(From Wikipedia)

Crystal Update

2007-12-09T18:34:00.002-05:00

The salt crystal gardens continued growing, without any additional ingredients for several days. Eventually, they began to wilt a little.
Here again is the progression:

Which stage do you think is the best?

As for the big alum crystal...

our seed crystals came out SO small that we couldn't work with them.

So we're going to try melting them down (just that little spice container was three bucks)

and start over. I found, and then lost, a link to tips for growing better crystals.

When I find it again I'll add it here.

Periodic Tables and Lego Molecules

2007-12-04T23:44:00.000-05:00

Becky over at Farm School at Home, a homeschooling blog out of the Canadian wilderness, had a post last week featuring an avalanche of periodic table links. Following a Lego Periodic Table link led me to a University of Wisconsin - Madison site featuring molecules built out of Legos -- with instructions. (The DNA Lego molecule above is from the Lego website -- I had trouble getting an image from the UW-M PDF instructions.)

I'll have to get the kids on this project!

Farm School: Cybils Review: The Periodic Table: Elements with Style!

(Scroll past the book review for the links)

What is alum used for?

2007-12-04T20:54:00.003-05:00

Long-Haired Hare

We're trying another crystal project from About.com, growing giant crystals of alum. Alum -- or hydrated aluminum potassium sulfate, KAl(SO₄)₂^.12H₂O -- is sold in outrageously expensive little containers with the spices. It's used to make pickles crispy.

The kids wanted to know more, so we looked it up on Wikipedia.

You'll find alum in styptic pencils to staunch the bleeding from shaving, and underarm deodorant, because of both its antibacterial and anti-wetness properties.

Oh, and it's an astringent, which is why they can use it in Looney Toons cartoons to shrink heads. And you thought the only thing kids learned from watching Bugs Bunny was classical music!

It's Alive!

2007-12-04T20:25:00.000-05:00

By this morning Anthony's crystal garden was trying to climb out of the bowl.
As the day progressed, the turquoise food coloring stopped spreading,
and the bulbous projections sprouted white tips.

John's garden sprouted nicely overnight as well.
Tonight it looks like a bunch of miniature multicolored Afro wigs.

How does your crystal garden grow?

2007-12-03T20:02:00.002-05:00

Very well, thank you!

We changed the ingredients...
Mixed them together BEFORE pouring them over our sponge bases...
And in just a few minutes...

Crystals!
Anthony used double the amount of bluing, so his salt solution is more dilute.
(You can see a crystal formation climbing up the side of the bowl.)

John put some dots of food coloring on his.
(Note that the red spots grew the least.)
(I am very happy.)

Chemistry Stocking Stuffers

2007-12-02T17:55:00.000-05:00

The Joy of Toys was the theme of National Chemistry Week a couple years ago. This site has explanations behind toys like color changing rubber duckies, palm boilers and 3D glasses.

Crystal Garden continued

2007-12-01T22:48:00.000-05:00

Day 2 Day 4

Our damp blue piles of salt are not as garden-like as I hoped. I knew there were different versions of this project, but I wanted to try the easiest first. Now that we have proved it's not so simple (at least not for us), I've done some searching and found some areas to fiddle with:

We can use distilled water instead of tap water.
We can use un-iodized salt.
We can add ammonia to the mix.
We can combine the ingredients first, letting the salt dissolve in the liquid, before pouring over the base.
We can use less stuff or a bigger base.

Barring major snowstorm, we will try to get ahold of some distilled water, un-iodized salt, and some aluminum pie pans and give this another go on Monday. Maybe I'll also pick up one of these:

Amazing Christmas Tree

Now Appearing on GeekDad

2007-11-29T21:47:00.000-05:00

Just created my first post for the GeekDad blog on Wired.com. Yes, they know I'm not a dad. No, I'm not going to start lobbying them to change it to GeekParent. (Not yet, anyway.)

Crystal Garden Day 1 (if we're lucky)

2007-11-28T12:03:00.002-05:00

My next Hands-On Learning column for Home Education Magazine will be a crystal-growing project, and there are several versions I want to try. The one we started today comes from The Joy of Chemistry and uses Mrs. Stewart's Bluing. (You can also find the directions, an explanation -- and anything else you ever wanted to know about this old-fashioned, non-toxic laundry product -- on their website.)

We combined aspects of both sets of directions. Per JoC, we used an ordinary kitchen sponge, cut into cubes, as the base. But we left out the ammonia they recommend to see if it would work without, since MSB's website said it was helpful but not necessary. The sponge bits were sprinkled with water, salt and bluing.

As you can see, it really is BLUE. Prussian Blue, to be exact. According to Wikipedia, the chemical formula of PB is Fe₇(CN)₁₈(H₂O)_xwhere 14 ≤ x ≤ 16.

The PB is insoluble. The Mrs. Stewart's liquid is not a solution, but a colloidal suspension in which very tiny particles of the dye are floating. These small crystallites serve as seeds for the salt crystals that (hopefully) will be growing over the next few days.

Hah! I love it when I sound like I know what I'm talking about!

Saturated Solutions and Precipitates

2007-11-27T22:11:00.003-05:00

As an introduction to crystal-growing, I thought it would be helpful to talk about solutions. We did two experiments from Chapter 9 of The Joy of Chemistry: precipitating baking soda out of water using table salt (known as "salting out"); and salting out solid soap from liquid dishwashing detergent.

(You will notice that I thought it would OK to skip the hazmat gear for these demonstrations!)

First we made a saturated solution of baking soda in water, by pouring four heaping plastic spoons of the powder (how's that for precision?) into 2 cups of water, stirring, and waiting for the excess to settle out.

Then I "decanted" off the liquid into a cup for each kid, who marked it and filled a second cup with an equal amount of tap water. Equal small amounts of salt were added little by little until a change could be detected.

As with most of the experiments we've done so far from this book, the results were very subtle. The baking soda solution became slightly cloudy when we added salt, as compared to a cup of plain water.

Then we got new cups, put about a quarter inch of dish detergent into the bottom of each and sprinkled it with salt. The directions were incredibly vague: "liquid soap" and "sprinkle" were all they said. Anthony only sprinkled a small amount, but I let John pour it on, just to see what would happen.

In both cups we got a goopy mixture in the liquid. The book referred to this as "solid soap." The kids called it "wet salt." I wasn't sure how to tell the difference. Some ways now come to mind:

We could have wet some salt with water and noted the difference.
We could have tried putting another granular substance -- sugar, or sand -- into the soap to see if we ended up with the same kind of gelatinous goop.

Maybe we'll try this again.

A link from Bangalore

2007-11-27T22:01:00.000-05:00

Just something clever I stumbled over ... photos of experiments displayed at Science in Action, organized by the Bagalore Association for Science Education at Jawaharlal Nehru Planetarium Aug. 5-7, 2005.

Scroll down to see the photos of the kids' experiments. Many of the explanations are clear enough that you could probably recreate them at home.

Bill! Bill! Bill!

2007-11-27T10:47:00.000-05:00

Happy Birthday Bill Nye!

(Boy, that spinning head used to freak out my youngest when he was a baby...)

Like Na and Cl

2007-11-24T23:01:00.000-05:00

That's how much Pierre and Marie Curie were meant for each other.

Like "Young Tom Edison" and "Edison the Man," this 1940s biopic about the life and work of Madame Curieis a little dated in the way it makes its larger-than-life subject seem a little more human. And yet it is sweet and absolutely watchable.

I just opened Eve Curie's biography of her mother, upon which the movie is based, last night. Our library's copy is so old, a school girl's notes for a book report dated 1978 fell out from between the pages. Oliver Sacks tells of giving a speech in which he calls it the best biography he ever read -- then notices an elderly lady in the audience smile in approval. After the lecture, Eve Curie autographed his original copy for him. (Apparently, he carries it with him!)

Some interesting chemical moments in the film include watching the Curies distill tons and tons of pitchblende down, using acids and hundreds of evaporating bowls, until they are left with only a sample of pure radium so small it looks like a stain on the bottom of the bowl. What did they do with all the uranium they discarded? Was the small burn on Marie Curie's palm really the only damage the radioactive material did to the scientists?

I'll have to read the book to find out.

Out of Print

2007-11-22T12:14:00.001-05:00

The Visual Dictionary of Chemistry by Jack Challoner is, like all DK/Eyewitness books, a great reference, with photos and illustrations that make concepts clear like no written description or analogy can. If atoms don't really look like little planets, what do those electron orbitals really look like? Go to page 10 and you'll see. How does a Buckyball differ from graphite and from diamond? See page 42. What's the right way to demonstrate a thermite reaction without burning a hole in the linoleum? Check out page 29.

However, since this nifty volume is out of print, I can't add it to my Amazon list. So go visit Ebay's non-auction cousin, half.com, and pick up a used copy.

Science is Fun

2007-11-20T21:05:00.000-05:00

According to his website, www.scifun.org, University of Wisconsin-Madison chemistry professor Bassam Shakhashiri is "known internationally for his development use demonstrations the teaching of chemistry classrooms well in less formal settings such as convention centers, shopping malls and retirement homes." Shopping malls!

A nice-looking site with Experiments You Can Do at Home, a Chemical of the Week archive, and lists of chemistry books and websites, all suitable for kids middle school and up.

An interesting note: Many of my favorite websites for teaching history to kids belong to elementary or middle school teachers, but so far the best resources for chemistry at home seem to come from college professors. There are also a few good ones for preschoolers and younger kids -- but where are the middle and high school chemistry teachers? Are they all too busy cramming facts into the kids for the SATs?

Chem4Kids

2007-11-19T12:17:00.001-05:00

In addition to reading through The Joy of Chemistry together, I'm thinking of having the kids go through this site on their own. I like the way it explains complex topics in simple language, and I think it might help clarify or reinforce concepts like bonding, stoichiometry and even anti-matter! The pages aren't cluttered, and it's got really nice graphics to explain the concepts in a visual way. And there are online quizzes they can take to see how much they actually absorbed.

No experiments this week --we have a bunch of kids coming over for a birthday party, and I've got to put all the dangerous stuff away. But we should start growing crystals next week, for a Hands-On Learning column I'll be writing for Home Education Magazine.

Molecule of the Day

2007-11-16T10:19:00.000-05:00

In keeping with my determination to look at molecules (meaning, for the most part, their graphic representations) with the kids, I've added a new website to the Learn About Chemistry list.

Here's MY molecule of the day: 1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione, also known as caffeine. I've seen the tee shirt above at my neighborhood coffee emporium. Very cool.

Sensory Creatures

2007-11-15T21:54:00.001-05:00

Went to the Roald Hoffmann talk last night. John (who just turned 15), accompanied me and said he enjoyed it. (It's Hoffmann's wry asides, missing in his video appearances, that make him so engaging in person.) In preparation, we watched the first episode of World of Chemistry online. Then I served two different enantiomers of carvone for lunch: homemade pumpernickel rolls with caraway seeds and spearmint candies. (The rolls came out a little dry; I'll have to find a better recipe.)

In our interview, I had asked Hoffmann what he does to make chemistry more accessible to laymen. He described a typical news item about science, a health story either touting a new miracle drug or decrying the fact that last year's miracle drug has been found to have dangerous side effects. He went on to say

The newspaper will never show a picture of the molecule. They’re deathly afraid to show the molecule. But they will use the name. So when I see that story, I go to Wikipedia and get the structure to show them, and go deeper into the story.

So I made sure to show the kids pictures of the right- and left-handed carvone molecules. And I will try to post images of molecules here whenever possible.

Again, if you can get to the Tang Museum to see the Molecules that Matter exhibit do so, if only to get to walk around the giant steel 3D molecular models. As Hoffmann pointed out last night, computer graphics have pretty much made model-building obsolete. But humans are sensory creatures, and the real-life experience is more profound than the most detailed rotating 2D approximation.

Young Tom Edison

2007-11-14T22:51:00.000-05:00

Borrowed the 1940 film from the library and sat down with the kids yesterday to watch it. (This was actually for history as much as science; I asked the kids to research inventions, and Anthony picked the movie camera.)

Although Thomas Edison is known for electrical inventions, there was a lot of messing about with chemicals in this biopic. First he fills the schoolhouse cloakroom with smoke, trying to see if concentrated ammonia and hydrochloric acid mix. (In real life, Edison's mother taught him at home after he was kicked out of school.) Then he stops a train when they find out he's got a bottle of nitroglycerin on him.

(Swedish chemist Alfred Nobel became rich developing a safe form of nitroglycerin: dynamite. After his death, he dedicated his wealth to the establishment of the prize named for him.)

It certainly had its hokey side, but the film was touching at times too. And amazingly, most of the unbelievable incidents are actually true. Edison really did start a boyhood business selling newspapers on a train and did chemistry experiments in the boxcar. saved a child on the train tracks and learns Morse Code from the boy's grateful father.

Not a bad little flick, if you're in the right mood. I'm hoping to pick up the sequel, Edison the Man, starring Spencer Tracy, for next week.

Chalk and Vinegar

2007-11-13T21:10:00.001-05:00

A big piece of sidewalk chalk sitting in a glass of vinegar, not really doing much of anything.

Lesson: Carbon dioxide is heavier than air
What Happened: CO2 collected in a glass can be poured out so that it extinguishes a candle

Last week a friend who used to teach chemistry at a local community college brought her son over for the afternoon. I had bought some Diet Coke and Mentos for the kids to try outside. My friend's son let my boys take his turn, while he played the role of "brave photojournalist."

I also got my friend to try a demonstration I read about in Uncle Tungsten, and which is mentioned in passing in Joy of Chemistry as an example of the effects of acid rain. It involves dissolving a piece of chalk in a glass of vinegar. My friend and I tried Crayola brand blackboard chalk from Wal-Mart but did not get much of a reaction. Old sidewalk chalk, much thicker and softer, worked a little bit. But for the second half of the demonstration, we had to resort to baking soda.

In Uncle Tungsten, Oliver Sacks describes watching his mother "pour" off the carbon dioxide accumulating in the glass over a candle, which goes out. That's the part of the demonstration I was interested in seeing. A small amount of baking soda and vinegar -- not enough to bubble out of the glass -- did indeed produce enough CO2 to recreate Sacks' childhood memory.

In addition to proving that carbon dioxide is heavier than air, we also demonstrated that even middle-aged moms like to mess around with concoctions. Sometimes more than their kids.

NOTE: Chalk is made of calcium carbonate, a base, the same stuff in limestone and marble. Vinegar is acetic acid. The reason our chalk didn't react very much with the vinegar was that it contained other substances. A little Googling revealed Prang Hygieia, 95% calcium carbonate, as the brand of choice for this demonstration. If I get ahold of some I will give it another go.

Roald Hoffmann

2007-11-12T11:50:00.000-05:00

My preview of Nobel Prize-winning chemist Roald Hoffmann's upcoming talk at Skidmore College can be read here.

And David Brickman has gets a little more humanity into his preview of the same event.

I think I was a little nervous for this interview.

I hestitate to post a link to the World of Chemistry parodies mentioned in the story (I haven't watched them through and don't know how mean they get), but blogger Jennifer Saylor, who watched the series in her junior college chemistry class, has an an interesting take on its appeal:

I’m a huge fan. The videos are utterly dorky, and I find the series irresistible for its awkward charm and nerdiness. If I could get the DVDs from my local video store, I would watch them all.

(In the sidebar is a link to a streaming video of the entire series.)

And here's a poem by Hoffmann, that I didn't have room for in the story:

MEN AND MOLECULES

Cantilevered methyl groups,
battered in endless anharmonic motion.
A molecule swims,
dispersing its functionality,
scattering its reactive centers.
Not every collision,
not every punctilious trajectory
by which billiard-ball complexes
arrive at their calculable meeting places
leads to reaction.
Most encounters end in
a harmless sideways swipe.
An exchange of momentum,
a mere deflection.
And so it is for us.
The hard knock must be just right.
The eyes need lock, and
glimmers of intent penetrate.
The setting counts.
A soft brush of mohair
or touch of hand.
A perfumed breeze.
Men (and women) are not
as different from molecules
as they think.

Silly Putty

2007-11-08T11:28:00.001-05:00

During World War II, the Japanese blocked the US from importing rubber. The government asked the chemical industry to find a substitute. James Wright, an engineer working for General Electric, created a polymer from silicone and boric acid. Dr. Joe Schwarcz describes what happened next in his book The Genie in the Bottle:

The pliable mass could be rolled up into a ball and bounced 25 percent better than a comparable rubber ball. Here was the desired property. Unfortunately, the substance had some undesirable properties as well. When you hit it with a hammer, the stuff shattered; when you pulled it quickly, it broke apart. A fascinating but useless substance.

GE sent samples to engineers around the world, hoping to find a suitable application. Then, in 1949, some of the putty fell into the hands of toy shop owner Ruth Fallgatter. Although it outsold everything in her shop's catalogue (except for Crayola crayons), Fallgatter lost interest. But the marketing consultant she hired, Peter Hodgson, repackaged the gooey slime in plastic eggs and Silly Putty was born.

Yesterday I took the kids to the Schenectady Museum for the second in a series of science workshops for local homeschoolers. (Schenectady, of course, was once GE's "Electric City," and the museum is home to lots of GE memorabilia and Edison artifacts.) This month's topic was chemistry, and one of the hands-on projects the kids got to do was to make a version of Silly Putty from Borax (a type of laundry soap) and Elmer's glue. This is a standard little-kid chemistry demo; there were three booths featuring it at last month's New York State Museum Chemistry Week event. (Here is about.com's recipe.) Unfortunately, given the current trend away from experiments involving any degree of risk, it also seems to have become a standard big-kid chemistry demo as well.

The homeschool workshop description talked about having the kids make several types of putty and recording their observations (how high they bounced, etc.) I thought maybe they would be using different formulas. (For instance, there are a variety of recipes here.) What they did was give the kids was different concentrations of borax and glue. John came home with a bag of goo; Anthony didn't have time to finish all three versions, so he didn't end up with a playable mixture. We'll have to do this again at home.

Considering that this program was for kids up to age 14, it would have been nice if they included a few more facts, too. Such as the chemical names and formulas of the different substances the kids used. So here is a look at Borax (sodium borate - Na₂B₄O₇) and the Elmer's Glue ingredient polyvinyl acetate, courtesy of Wikipedia.

When you combine them, the sodium borate from the borax acts as a crosslinker to link the chains of polyvinyl alcohol together, resulting in a big gooey mass of slime.

(There's more to it, of course, but the full explanation I found from Newton Ask a Scientist is beyond me.)

NOTE: Real Silly Putty is made from boric acid and silicone, both easily-obtainable substances. However, I've seen the reaction to combine them described as "violent," so perhaps it's best to stick with Elmer's and 20-Mule Team -- at least at home!