Now that you know how to find acids, you are ready to see what an acid can do to a common kitchen item.

QUESTION

How can you peel a raw egg?

MATERIALS

Raw egg

Vinegar

Small glass

PROCEDURE

• Place the egg into the glass.

• Pour enough vinegar into the glass to cover the entire egg.

• Let it sit for a few days.

• You should return to find that the eggshell has disappeared and your raw egg has become see-through. You may need to rub the surface to remove the last parts of the shell.

WHAT'S HAPPENING

The acid in vinegar slowly ate away at the eggshell until none of it remained. When you returned to find the see-through egg, you were really seeing the thin membrane that holds the egg inside the shell. You may have noticed quite a bit of bubbling during the “peeling” process. Eggshells are made of calcium carbonate, which reacts with vinegar (an acid) and makes calcium acetate, carbon dioxide (the bubbles you see), and water.