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Kitchen Chemistry 101
A Fun Way to Cook Up a Healthy Interest in Science
By Laura Zurita, RD,LDN

In the kitchen, basic principles like chemistry, physics and microbiology abound and help us make and enjoy what we eat. Rising cakes, browning of toast, and the ripening of fruits are some practical examples that illustrate these concepts.

Try a few of the following one lazy afternoon. You may spark your children’s interest enough to make a trip to the library or to factor in some internet time devoted to science.

Bubble “Surprise”

Since this may be messy, do it outside, in a large sink, the bathtub, or another area that can get wet.

Supplies: water, zipper lock plastic bags (quart or gallon size), fresh box of baking soda, vinegar, and paper towels.

1. Place about two tbsp. of baking soda in the center of a paper towel square that has been trimmed to 5” x 5” and marked to be divided into thirds. Fold the towel in on both sides, with the baking soda in the middle third. Flip up both ends to make a square.

2. Pour 1/2 cup of vinegar and 1/4 cup of warm water into the bag.

3. Carefully place the paper towel into the bag without touching the liquid, zip the bag, and then let the towel “drop” down to the liquid.

4. Stand back and watch for bubbling action.

The Science Behind it: The bubbling action you see is a gas, carbon dioxide, that forms when the vinegar (an acid) reacts with baking soda (the base). It’s the classic acid-base reaction from Chemistry 101.

The same principle happens in a quick bread recipe, where the reaction causes the bread to rise, and the “structure” is formed with the flour. Check cookbooks for one to try. Sometimes the acid comes from buttermilk or milk soured by vinegar, or from an acidic juice like orange.

“Magnetic” Cereal

This experiment will literally get your kids attracted to science—and breakfast.

Supplies: iron-fortified cereal flakes, spoon, bowl, strong magnet.

1. Crush the cereal into particles smaller than the flakes.

2. Take the magnet and “roll” it in the cereal.

3. If the magnet is strong enough, you will see clumps of the particles “sticking” to the magnet.

The Science Behind it: Iron, a mineral important in the formation of red blood cells in your body, is attracted to the magnet. It is often added to cereals so that we get this much-needed nutrient.

Lemon Magic

Supplies: 1 apple, 1 lemon, knife.

1. Cut an apple into four quarters.

2. Put one quarter into the refrigerator, leave one on the table, and sprinkle two with lemon juice from the lemon. Place one of them in the refrigerator.

3. Wait 30 minutes. What happens? Did the ones with lemon juice turn brown?

The Science Behind it: When apple cells are “broken” with cutting, they are exposed to oxygen from the air, and an enzyme (a chemical) reacts with the oxygen and causes browning. Lemon juice, an acid, stops the enzyme from reacting.

The Naked Egg a.k.a. the Disappearing Shell

You have to have patience for this one, but the end result will mystify your children, that is until you tell them the answer.

Supplies: eggs, container with lid, white vinegar.

1. Place one or several eggs in a container and try not to have them touch.

2. Cover with vinegar.

3. Observe the bubbles forming on the shells.

4. Cover the container and place in refrigerator for 24 hours.

5. Take out container, carefully remove eggs one by one with a slotted spoon to a safe place.

6. Pour out vinegar.

7. Place eggs back into container with new vinegar, cover, refrigerate for 24 more hours.

8. The eggs should now be minus their shell, and you can see the yolk and white through a thin membrane.

The Science Behind it: Another acid-base example. The vinegar (acid) dissolves the calcium carbonate (base) of the shell. The calcium dissolves into the vinegar, and the carbonate becomes carbon dioxide (the bubbles you see).

Laura Zurita is a registered and licensed dietitian, food technologist, and educator. Her passion is communicating information about nutrition and the science of food to all types of audiences. Currently she is a mostly stay-at-home mom in New Jersey.