Monday, October 22, 2007

Good Chemistry

My Times Union story can be read today at The editor added some nice experiments and "fun facts."

UPDATE: Here's the story, which is now available here


Finding the right formula for budding scientists a challenge
Section: Life-Discovery,  Page: C1
Date: Monday, October 22, 2007

Anthony, my 11-year-old, had already made oobleck from corn starch and water, leaving dried traces of the quicksandlike mixture on the back deck. Now the boys helped me carry window cleaner, lemons and other kitchen things out to the small table on the lawn. One by one, we added bits of each substance to cups of purple cabbage juice, watching each cup turn a different shade, from turquoise to pink. John, the 14-year-old, was impressed that we didn't even need any ``proper chemicals.''

Afterward, we arranged the solutions according to their acidity or alkalinity, then turned some pink vinegar back to purple - and blew up a balloon on top of the bottle - by adding baking soda to the vinegar. Physical change versus chemical reaction: our first official chemistry lesson at home.

As a homeschooling mom and the hands-on learning columnist for Home Education Magazine, I'm used to doing all sorts of projects with my kids at the dining room table. But when it comes to chemistry, my head starts to spin. Unlike the "6 out of every 6.0225 Americans" who insist they flunked high school chemistry (according to science writer Natalie Angier's book "The Canon"), I passed my tests, but was left with sour memories of balancing equations and experiments that just wouldn't work.

So I was intrigued to read Oliver Sacks' 2001 memoir "Uncle Tungsten," about the famous neurologist's early fascination with chemistry. Young Sacks loved to test samples obtained from his Uncle Dave, a manufacturer of light bulb filaments, in an unused back laundry room of his house - handy for flinging out-of-control reactions into the yard.

I decided I wanted my kids to discover a little of that fun, too (within reason). What I learned, however, is that doing chemistry at home is a lot harder than it used to be.

The old chemistry set

In the 1940s and '50s, every boy seemed to own a chemistry set (many girls, as well). In fact, the toy gave many scientists of that generation their start.

"I got my first chemistry set when I was 12 years old, in 1944," says Samuel C. Wait Jr., chemistry professor and acting dean of the School of Science at Rensselaer Polytechnic Institute. "I had very understanding parents. They let me go down to Walker's Drug Store in Schenectady and buy any chemicals I needed."

One time, he recalls, "I was making Bakelite, a resin involving formaldehyde and phenol, in my unventilated basement. Obviously, the fumes were pretty strong. I put it in the oven in the kitchen when my mother had her bridge club over. They didn't appreciate the smell."

Luckily for Wait, the hypervigilant parent had yet to be invented, and his hobby was allowed to continue.

Still, by the end of the 1960s, according to the Chemical Heritage Foundation, safety concerns started winnowing down the chemicals and experiments that chemistry sets contained. No longer could children find out how to mix iodine crystals and ammonia and produce a "Safe Explosion" (as CHF chemist Mark Michalovic demonstrates for Wired Science on the PBS Web site,

Porter Chemcraft, Gilbert and other big chemistry-set makers went bust. Today many of the chemicals in those sets wouldn't be allowed in a college freshman course, Wait admits, "but they were a lot more interesting!"

In contrast, the new generation of science kits often boast nothing more exciting than borax and coffee filters. It's a cultural change that many college educators cite as a cause for the drop in interest in chemistry. (See related story on Page C3.)

`Real' experiments

That's not to say parents should send their kids off to mix up toxic cocktails. But for families ready for more of a challenge than invisible ink, the choice seemed to be stripped-down kits and books, or manuals for high school teachers with lots of lab experience. What we needed for homeschooling, I realized, was a book of "real" chemistry experiments for people who had the interest, but not a formal background or lab.

Enter Monty L. Fetterolf, chair of the Department of Physics and Chemistry at the University of South Carolina at Aiken, and his wife and fellow USC professor Cathy Cobb, a writer specializing in science books for lay readers. Their book, "The Joy of Chemistry: The Amazing Science of Familiar Things," calls itself "a chemistry book for the armchair scholar, to be perused in the comfort of one's home and enlivened with straightforward demonstrations that can be carried out in the kitchen or garage."

Although the book is intended as "a virtual adult chemistry set," Fetterolf says he's heard from high school teachers and homeschoolers searching for a guide to exploring chemistry with items around the house.

And that's what "The Joy of Chemistry" is designed to help readers do. The shopping list includes such everyday chemicals as fingernail polish remover (acetone), laundry bluing (ferric hexacyanoferrate), and pH-lowering solution for fish tanks (sulfuric acid). Paper plates, plastic cups and microwave ovens stand in for lab glassware and Bunsen burners.

"We did not want people intimidated from trying these fun things because they didn't have a beaker," Fetterolf says.

Lab experience

Whether we'll make it through all the book's demonstrations remains to be seen. But if we do, Fetterolf says, my kids will have as valuable a lab experience as any incoming college freshman. Whether they use an eye dropper or a pipette, "the concept is understood."

And, he adds, the breadth of topics covered - from key concepts such as reduction/oxidation (redox) reactions to fields of study like organic chemistry - will give them almost everything they'd get from a good high school introduction - except for the math.

"We knew if we included the math," explains Fetterolf, "it would turn people off. (But) you don't need to calculate anything to appreciate the concepts."

I was hoping that "The Joy of Chemistry" shopping list would solve my own chemistry set dilemma. But even for adults, it's getting hard to find many chemicals that once were common. In the four years since Fetterolf designed the book's demonstrations, pure lye drain cleaner has disappeared from grocery shelves (probably because of its use in making methamphetamine).

And I haven't yet located saltpeter, used in pickling, garden fertilizer and, not encouragingly, gunpowder. It's telling that Fetterolf and Cobb's new book "Crime Scene Chemistry for the Armchair Sleuth" now sends readers to the Internet rather than the store for most materials.

Safety's still on my mind, too. I went to Mary-Jane Rau Pelzer of Saratoga Suds, who's been making soap in her kitchen for more than 35 years, to ask about lye and got an earful about mixing caustic chemicals and kids. Even with precautions, Pelzer once suffered a severe chemical burn on her foot from only a few spilled grains of lye.

"Lye, in various concentrations, was frequently used by our ancestors for a variety of tasks, including processing corn for hominy grits and making soap," she explains. "They didn't have any alternatives. However, chores involving lye were not done by children. The premise that today's commercial-strength lye is `kid friendly' is an incredibly dangerous concept on many levels."

OK, so lye's out. But wary as I am about this venture, I'm still heartened by this tidbit from RPI's Wait.

"Two or three weeks ago in Chemical and Engineering News I was reading the obituaries of chemists," says the elder chemist, "and there were a dozen or so in their eighties. So it's not that hazardous to your health!"

Kathy Ceceri is a freelance writer based in Schuylerville.

Chemical connection


"The Radioactive Boy Scout: The Frightening True Story of a Whiz Kid and His Homemade Nuclear Reactor" by Ken Silverstein. A cautionary tale about what might be going on in the backyard shed when parents aren't paying attention.

"The Fly in the Ointment" by Joe Schwarcz. Part of a series of books of short, entertaining essays on chemistry from the Canadian radio host and professor at McGill University (my alma mater, where I did not take lab courses).

ON THE WEB Everyday explanations, experiments, even a teach-yourself-chemistry section at this amazing content-rich site, hosted by Anne Helmenstine, Ph.D. Steve Spangler started the Diet Coke and Mentos craze (look it up on his Web site if you don't know what this is). Shop his science store or browse his video archive of experiments suitable for elementary school-age kids. Where I'll be blogging about my family's experiments and visits to local museums, reviewing books, kits and Web sites, talking to chemistry experts, and more.

How to make red cabbage pH indicator

Acid-Base Chemistry

Red cabbage contains a pigment molecule called flavin (an anthocyanin). This water-soluble pigment is also found in apple skin, plums and grapes. Very acidic solutions turn anthocyanin a red color. Neutral solutions turn it a purplish color. Basic solutions turn it greenish-yellow. Therefore, it is possible to determine the pH of a solution based on the color it turns the anthocyanin pigments in red cabbage juice.

The color of the juice changes in response to changes in its hydrogen ion concentration (pH is the -logH+). Acids will donate hydrogen ions in an aqueous solution and have a low pH (pH 7). Bases accept hydrogen ions and have a high pH (pH 7).


red cabbage; blender or knife; boiling water; coffee filters; one large glass container; six small glass containers; household ammonia (NH3); baking soda (sodium bicarbonate, NaHCO3); washing soda (sodium carbonate, Na2CO3); lemon juice (citric acid, C6H8O7); vinegar (acetic acid, CH3COOH); cream of tartar (Potassium bitartrate, KHC4H4O6); antacids (calcium carbonate, calcium hydroxide, magnesium hydroxide); seltzer water (carbonic acid, H2CO3).


Place 2 cups of chopped cabbage in a large glass container and add boiling water to cover cabbage. Let it sit at least 10 minutes for the color to leach out of the cabbage. (Alternatively, you can place the cabbage in a blender, cover it with boiling water, and blend it.)

Filter out the plant material to obtain a red-purple-bluish colored liquid. This liquid is at about pH 7. (The exact color you get depends on the pH of the water.)

Pour about 50 to 100 mL of your red cabbage indicator into small glass. Add various household solutions/solids (from materials list) to your indicator until a color change is obtained. Use separate containers for each household solution/solid - you don't want to mix chemicals that don't go well together.


This demo uses acids and bases, so please use safety goggles and gloves.

Chemicals used in this demo may be safely washed down the drain with water.

A neutralization experiment could be performed using cabbage juice indicator. First add an acidic solution such as vinegar or lemon juice until a reddish color is obtained. Then add baking soda or antacids to return the pH toward a neutral 7.

You can make your own pH paper strips using red cabbage indicator. Take filter paper (or coffee filter) and soak it in a concentrated red cabbage juice solution. After a few hours, remove the paper and allow it to dry (hang it by a clothespin or string). Cut the filter into strips and use them to test the pH of various solutions.


Everyday chemistry

Why do onions make you cry?

When you cut an onion, you break cells, releasing their contents. Amino acid sulfoxides form sulfenic acids. Enzymes that were kept separate now are free to mix with the sulfenic acids to produce propanethiol S-oxide, a volatile sulfur compound that wafts upward toward your eyes. This gas reacts with the water in your tears to form sulfuric acid. The sulfuric acid burns, stimulating your eyes to release more tears to wash the irritant away.

How does soap clean?

Soap is an excellent cleanser because of its ability to act as an emulsifying agent. An emulsifier is capable of dispersing one liquid into another immiscible liquid. This means that while oil (which attracts dirt) doesn't naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed.

Why do we put salt on icy surfaces?

When you add salt to water, you introduce dissolved foreign particles into the water. The freezing point of water becomes lower as more particles are added until the point where the salt stops dissolving. For a solution of table salt (sodium chloride, NaCl) in water, this temperature is minus 6 degrees F under controlled lab conditions. In the real world, on a real sidewalk, sodium chloride can melt ice only down to about 15 degrees F.


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