ChemShorts for Kids   --   1998
Copyright ©1998 by the Chicago Section of the American Chemical Society

by Dr. Kathleen A. Carrado, Argonne National Labs

ChemShorts Home

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

January, 1998

Ocean in a Bottle

Ollie is a handyman,
The greatest one around.
He makes toys from odds and ends
And sells them by the pound.
While walking by the ocean,
And looking at the waves,
Ollie had a great idea -
A toy that would get raves!

Kids, here's how you can make Ollie's new toy for yourself. Fill a large clear plastic soda bottle halfway with water. Add a few drops of blue food coloring and mix. Add a light-colored cooking oil until the bottle is filled to the very top. Put the cap on tightly. Turn the bottle sideways and tilt it up and down. What happens? How does your ocean-in-a-bottle work? Oil and water do not mix because the molecules in water are very attracted to each other, but are not attracted to those in oil at all. Because water is more dense than oil, when the bottle is rocked, the water runs to the bottom, pushing the oil out of its way and making waves. Adding color to the water makes it easier to tell the difference between the two liquids.

Taken From: Apples, Bubbles, and Crystals: Your Science ABCs, by A. Bennett & J. Kessler, 1996, McGraw Hill, NY.

February, 1998

Fantastic Plastic

When Pam the great magician
Was eating lunch one day,
Some magic fans came over
And would not go away.
The people wanted magic,
But what was Pam to do?
She had her plastic lunch bag
But knew some science, too.

Kids, you can try what Pam did with her zip-closing plastic bag, a sharp pencil, water, and paper towels. Fill the bag almost full with water and zip it closed. Hold the bag over a sink. Slowly push the point of the pencil through one side of the bag, through the water. Push the pencil all the way through to the other side of the bag. The bag should not spring a leak. Why not? Plastic sandwich bags are flexible because of the long, stretchy molecules called polymers from which they are made. When a sharp pencil is poked through the bag, the polymer molecules slide away, and then flex enough to squeeze back around the pencil. This makes a tight, leak-proof seal. It also works for a balloon. Lightly oil a knitting needle, then poke it through the top of a blown-up balloon and out the bottom near the tied knot. Rubber tires on cars also work this way. A gummy layer on the inside of the tire seals around any nails or sharp objects that poke directly into the tire.
Taken From: Apples, Bubbles, and Crystals: Your Science ABCs, by A. Bennett & J. Kessler, 1996, McGraw Hill, NY.

March, 1998

Wax 'N Wash

Wally had a secret thought
That he just had to tell.
Wendy sat four desks away -
He did not want to yell.
How did our Wally do it
So no one else could see?
To send a secret message,
Some candle wax is key!

Kids, Wally and Wendy needed these few essential items to send secret messages: a sheet of white paper, a white candle, watercolor paint and paintbrush, and water. Make up a short secret message and write it on the paper with your candle. It will be hard to see but try your best. Paint over the entire paper with the watercolors. Now can you read the writing more easily? Why did Wally and Wendy choose wax to write their messages? All waxes contain fats or oils. Waxes are made from petroleum oil, animal fats, or plant oils. Watercolor paint has water in it. As you know, oil and water don't mix. Water molecules and oil molecules are simply not attracted to each other, and so the paint will just slide off the wax. The paint sticks to the paper because it is attracted to the paper fibers.
Taken From: Apples, Bubbles, and Crystals: Your Science ABCs, by A. Bennett & J. Kessler, 1996, McGraw Hill, NY.

April, 1998


Kids, have you ever built a sand castle at the beach? The sand "wets" easily with water to make a nice packing mud. Beach sand is mostly made of the mineral quartz (a form of silica, SiO2) that is broken into tiny pieces. In the jargon of chemistry, the surface of sand is said to be hydrophilic, or water-loving. But there is another type of sand that behaves very differently. "Magic" sand is coated with even smaller particles of chemically treated silica. This special surface treatment makes the sand hydrophobic, or water-hating. So what does this mean? Instead of sinking in water like beach sand, magic sand will float. A thick layer of magic sand will eventually sink, but it is surrounded by a silvery layer that is actually an air pocket. The clump can be molded underwater into any desired shape by hand. When taken back out of water, these sand grains are not clumped and are perfectly dry!

Magic sand was developed by chemists at Cabot Corp. with the idea that it could be used to cleanse water of oily contamination. Many materials that are water-hating, like magic sand, are oil-loving. When sprinkled on an oil slick, magic sand attaches to the oil, adds weight, and sinks. This theoretically allows oil to be dredged from the bottom and saves the coasts from an oil slick. It has also been tested by utility companies in the Arctic. When a junction box is covered with magic sand, buried lines can be serviced easily because the dirt does not freeze and remains dry and loose year round. Other proposed uses: a surface for horse-racing tracks, in golf course sand traps, in children's sandboxes, and around the foundations of homes.

There is a product available in toy stores called Sqand (RoseArt), for ages 6+, that is based on the principle of magic sand if you would like to give it a hands-on try for yourself. It is colorful, safe, non-toxic, and fun!

Reference: ChemMatters, April 1994, "Magic Sand" by D. Robson.

May, 1998

Food for Thought

Kids, have you heard of Bill Nye, The Science Guy? He has a fast-paced television show that we can highly recommend. Here we are going to summarize the show on nutrition. Both this column and Bill Nye stress that not all chemicals are necessarily "bad", and quite often they are absolutely essential. Take food, for instance. All food is made of chemicals, whether they're called protein, fat, carbohydrates, vitamins, or minerals. When your body gets ahold of these chemicals, it burns them up and makes energy for us to live on. Different types of food make different amounts of energy, which is measured in calories. How do chemists figure out the amount of calories in any certain food? They use an instrument of food science called a bomb calorimeter, which is not really a bomb at all but a container that measures the amount of heat liberated or consumed by a reaction.

Food is the body's fuel and, like a car needs gasoline, your body needs food to make energy and keep going. A balance of food from the major groups is essential to good health, and it's important to give your body enough food every day. However, too much of one type of food can backfire, so you need a balanced mix. Take fat, for instance. Fat cushions your body, keeps you warm, and gives your body lots of energy. Your brain is about 60% fat! Eating fat is important but too much can make you... well... fat. To get an idea of the presence of fat in your meals, try this fat-sensor experiment.

Cut a brown paper grocery bag into squares and label them with foods you want to test. Rub each different food onto their labeled squares. Although fun, there is no need to mash the food into a pulp. Set the squares aside for about 30 minutes, then hold them up to a light. It should be "clear" which foods have the most fat, for they will leave oily spots that are virtually transparent.

Reference: "Bill Nye, The Science Guy's" website is:

June, 1998

The Fun Side of the Periodic Table

Kids, have you ever seen an arrangement of small white boxes containing a collection of one- or two-letter symbols and bunches of small numbers? Chances are that, if you have, it was something that chemists use called the periodic table. You might even have one in your house if someone you live with has a chemistry or physics textbook, a scientific encylopedia, or access to the internet (try and click on "elements"). Nature and science discovery stores sell placemats of it, too. Look one up and try to figure out what the symbols stand for.

The table has information about every element found on Earth. After many years of studying chemical elements, scientists have discovered or created over 100 different elements. Every gas, liquid, solid, rock, metal, compound, and mixture in the universe is made up of some combination of these basic elements. In the typical periodic table, elements with common properties fall in the same column. The overall arrangement makes sense to chemists but it is highly technical and not very approachable for the young or non-scientist. Everyone can have fun with it, however, when a different and more light-hearted approach is taken.

One such presentation distorts the shape of the boxes of each element to reflect its relative abundance on Earth. This way the largest boxes contain the most commonly known elements, such as those for C (carbon), O (oxygen), and Si (silicon). Check this out in the Journal of Chemical Education, volume 70, page 658, August 1993. A sample chart with a full activity's description for elementary school students and teachers is provided.

In addition to this, some colorful charts for display can be ordered from various places, such as Aldrich Chemical Co. (800-558-9160), Gelest Inc. (215-546-1015), La Naturaliste in Canada (418-724-6622), and Time-Life Books published a giant poster in 1987. A company called "Food for Thought" will provide posters for "eaters and thinkers" of food items, vegetables, desserts or even animals in take-offs of the original (800-666- 5436). Have your parents or teachers check into these for you!
Submitted by: K. A. Carrado, Chair of Elementary Education Committee.

Compounds vs. Mixtures

Kids, sometimes it can be hard to figure out what someone means by a pure compound versus a mixture. Let's try to clear this up with an easy explanation and experiment. First, pure elements are what you see on the periodic table, and some materials exist naturally in their pure elemental form, like lead (Pb), neon (Ne), iron (Fe), etc. Some other elements are "diatomic", like nitrogen (N2 ), oxygen (O2 ), and hydrogen (H2 ) in their natural state. Then we have to deal with the compounds. These are pure materials made up of two or more elements on the periodic table and represented by a distinct molecule, like water (H2O) and ammonia (NH3 ) and sodium chloride (NaCl) salt.

Finally there are the mixtures. These are combinations of compounds and account for most of what you encounter during the day. Take salt water, for example. Mix some regular table salt in water and you have a mixture. It is not a new compound because you can't write a formula for salt water, rather it is a combination (a "homogeneous" one). Mix together salt with some white table sugar and you also have a mixture (a "heterogeneous" one). White sugar is a pure compound called sucrose. Other examples of mixtures are: milk (water, milk fat, proteins, lactose, etc.), blood (white blood cells, red blood cells - with hemoglobin molecules, water, platelets, electrolytes - salts, etc.), and dirt (silica or silicon dioxide or sand, decayed plants, moisture or water, etc.). It is much easier to make a mixture than it is to make a pure compound! Try to find some more examples of mixtures and compounds during a regular day.

------------- By: K. A. Carrado, Chair of Elementary Education Committee.

Chemistry in a Teabag

Kids, there are all kinds of interesting things to think about when someone dips a teabag into a cup of hot water to make their hot tea. Inside a teabag are the crushed up dried leaves of the tea plant. Most of a tea leaf is cellulose, which is the major structural material of all plants. Cellulose is a very long chain (polymer) of glucose molecules and it is does not dissolve at all in water. The tea molecules that will dissolve in water include tannins, flavonoids, and caffeine. In order to separate the molecules you don't mind drinking from the leaf pieces, a teabag is used. Did you ever see a coffee filter? The teabag material is a lot like that. It is a porous paper that can get wet but is strong enough to not break and let the leaves go through. So, in making a cup of hot tea you are also doing an extraction and a filtration - these are two tools that chemists use to isolate compounds. Try it yourself! You can also cut open a teabag and take a look at leaves before and after.

Tannins are actually a class of organic compounds, some of which are used to "tan" hides into leather, and some are used in inks and dyes. The brown color of tea is also due to flavonoids, which are organic molecules that are natural pigments. Volatile oils give the flavor. About 2-5% of tea leaves is caffeine. An average 5 oz cup of tea contains 25-75 mg caffeine (some people prefer decaffeinated or herbal teas instead).

The tea leaves are picked by hand, left to wilt, then rolled and dried. If they are allowed to ferment before drying, you get black tea. Partially fermented leaves gives oolong tea, and tea not fermented at all is the so-called green tea. The tea plant is a relative of the camellia, so botanists have named it "Camellia thea". It is an evergreen shrub or tree 9-60 feet high. The first indisputable reference to the medical use of tea is from a Chinese dictionary in 350 A.D., but some folks even say there is evidence that a Chinese emporer used it all the way back in 2737 B.C. And, since it is native to Indochina and India, tea was grown for drinking even before China used it as a medicine.

------------- K. A. Carrado, Chair of Elementary Education Committee.

Dinosaur Science

Kids, dinosaurs didn't write memoirs or take family photos. But scientists can dig up the real dirt about dinosaurs, thanks to fossils. The only proof scientists have of dinosaurs is their fossilized bones. Original bones are relatively soft and fragile things that cannot survive the test of time, especially not the past 65 million years when dinosaurs once lived. But luckily for us, when some dinos died their bones were covered by mud, rock, or sand. Under this protection and through the years of soil erosion, the bones absorbed minerals from the earth. These minerals made the dinosaur fibulas, mandibles, and other bones very, very hard and resistant to erosion.

It's not too hard (ha ha, get it?) to make your own fossil. First you'll need to cut a small sponge into a bone-like shape using a pair of scissors. Then fill a big bowl with enough sand to bury the sponge, and make sure it's completely covered. While stirring, add enough salt to a pitcher of water until the water becomes murky. Pour this salty water into the bowl of sand until it's thoroughly wet. Put the bowl in a sunny place. This really needs a lot of sunlight so it will take at least a week. Maybe even a few more days if the days are getting shorter and there is not so much sunlight. When at least 7-10 days have passed you can dig up the sponge. In this experiment the mineral that hardens the spongy bones into hard fossils is salt (sodium chloride).

Did you know that blue whales are even bigger than the biggest dinosaur, the brachiosaurus, which was 35 tons and 46 feet high? The smallest known dino was compsognathus; at 15 pounds it was about the size of a chicken. Excavate these recent books about dinos from a library: "The X-Ray Book of Dinosaurs" by K. Severin (Franklin Watts Pub., 1994), "Dinosaurs: Strange and Wonderful" by L. Pringle (St. Martin's Press, 1995), and "Inside Dinosaurs" by T. Dewan (Doubleday, 1993).

Thanks and acknowledgements to: "Bill Nye: The Science Guy" at Submitted by: K. A. Carrado, Elementary Education Committee.

"D" is for Dissolve

This column is for you real little ones - those of you who have just begun school and are learning your letters. You will learn the letter "D, d" with the basic scientific concept of dissolving something. Get a clear plastic cup, water, a pencil, a paper towel, a twist-tie, and a kool-aid packet.

Carefully cut the paper towel into four equal squares. Place about one teaspoon of Kool-Aid in the center of a square. Fold it shut and close it with a twist tie. Tie the ends of the twist tie around the center of a pencil. The pencil acts as a support rod to dangle the kool-aid packet into the empty cup - just place the pencil down lengthwise on top of the cup's opening. Pour water into the cup until it just touches the bottom of the packet. Observe for a while, then add some more water.

Write your name on a sheet of paper and a title: "D d Dissolve" to practice your "d's". Then draw pictures of four simple cups. On two of them, draw your pencils and packets as well as you can. Draw in water levels on all four cups. (Or your teacher or a parent can have these already drawn for you). Now draw what happens when (1) the packet barely touches the water (2) the packet is soaked in water (3) when crystals are sprinkled directly to the water (no packet), and (4) after some time has passed. Using the paper towel, a type of "schlieren" effect occurs, like when heat waves are seen over a hot surface. You can also try other materials to test whether or not they will dissolve, such as table salt (yes), sugar (yes), or sand (no).


Thanks and acknowledgements to Marlisa Ebeling, a primary level teacher in Naperville District 203.

Updated 5/21/09