Acid / Base Art

You can have some fun with the color-changing properties of cabbage leaves. Simply draw a picture on a sheet of paper using a waterproof marker. Then color the shapes in by rubbing a cabbage leaf on the picture so that everything is reddish-purple. Then use cotton swabs and lemon juice or baking soda to change the color wherever you want. Let the picture dry and display your artistic creation!

Acid Or Base?

There are certain chemicals, called indicators, that turn different colors when they are added to acids, or to bases (acids' opposites). You can easily make an indicator out of something you might already have in your fridge - red cabbage!

What you'll need:
Red cabbage (fresh, not the kind in a jar)
Water
Lemon juice
Egg white
Baking soda
Vinegar
Cotton swabs
Small plastic cups
Plain white paper

Tear off a cabbage leaf and rub the dark red part onto the piece of paper until you see red marks. Make five spots, each about 1 inch (2.5 cm) in diameter. Pour a little of the water, lemon juice, egg white, and vinegar into four plastic cups. Dissolve about 1 teaspoon (5 mL) of baking soda in 1/2 cup (125 mL) of water in another cup. Dip a cotton swab into one of the liquids, then touch it to one of the red spots. Do this for all five liquids. What do you see?

Amazingly, the spots sometimes change color! The lemon juice and vinegar (both acids) turn it into an orange-red shade, and egg white and baking soda (both bases) make it greenish blue! Only water (which is neither an acid nor a base) doesn't cause a color change. The cabbage juice contains chemicals that act as indicator, and when they react with either an acid or a base, their atoms get rearranged into forms that have different colors. So if you have a liquid, but aren't sure if it's an acid or a base (or neither), you can test it with this indicator. Test a few other light-colored liquids to see what they are!

How to Cook Your Veggies

You know that you have to eat your vegetables, even though you may not like to. Did you know that how you cook vegetables affects how they look? Here's a simple experiment that you can do!

What You'll Need:
3 small, micowave-safe bowls
Measuring cup
Measuring spoons
Vinegar
Baking soda
Water
Microwave oven
Oven mitt
Spoon
Frozen green vegetable, such as peas

Pour 1/4 cup of water into each bowl. Add 1 tablespoon of vinegar to one bowl, and add 1 teaspoon of baking soda to another one. The third bowl should only have water in it. Add about 1/8 cup frozen vegetable pieces to each bowl (about 20 peas, if that's what you're using). Cook all three bowls in the microwave using high power for about 5 minutes. It doesn't matter whether you do them one at a time or all at once. When they're done, carefully remove the bowls from the microwave with the oven mitt. They will be very hot!!! Compare the vegetables - look at their color and mash them with a spoon to check their texture. What do you see?

You'll immediately notice that the vegetables cooked in vinegar (an acid) look grayish and very yucky. Who would want to eat them? The veggies cooked with baking soda (a base) look nice and green, but they are disgustingly mushy when you mash them with a spoon. Why do they turn out so different?

The green color is due to a molecule called chlorophyll, which has a magnesium (Mg) atom in the middle. Cooking in acid removes the magnesium and puts two hydrogens (H) in its place. The H-containing version of chlorophyll is a dull, ugly green color, and that's what you see. Cooking in a base doesn't remove the Mg, but it does break down the walls of the plant cells that keep the vegetable nice and firm. Without those strong walls, you can easily smoosh the cells together using a spoon. Vegetables cooked in water only keep a pretty good green color, and don't get mushy. Which one would you like to eat??