National Chemistry Week - Experiments - The Disappearing Egg Shell
to remove the shell from an egg without breaking the egg
What you will need:
- 1 glass jar
- 1 hard-boiled egg (A raw egg can be used but it can be
messy if it accidentally bursts.)
- 250 mL (1 cup) of vinegar
What to do:
Place the egg in the jar.
Cover the egg with vinegar.
Encourage the class to make observations immediately
and 24 hours later.
Bubbles will immediately form on the surface of the egg and
will increase in number over time. The bubbles are carbon dioxide
gas. After 24 hours the shell is gone. The membrane of the egg
remains. The chemical name of vinegar is acetic acid and egg
shells are made up of calcium carbonate. There is a chemical
reaction between the vinegar and the shell. This is what causes
the bubbles to form initially and what causes the shell to
Allowing the egg to react with the carbon dioxide in the air
will cause the egg to harden again. Chalk is also made up of
calcium carbonate. What would happen to a piece of chalk if it
was placed in vinegar?
For other chemical reactions with an acid see GREEN PENNIES,
IN KNOTS and THE ERUPTING VOLCANO.