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Vinegar is an acid. Eggshells are made of calcium carbonate. If you soak an egg in vinegar the eggshell will absorb the acid and break down, or dissolve. The calcium carbonate will become carbon dioxide gas. What is left is the soft tissue that lined the inside of the eggshell. Today’s experiment is similar to the Bouncing Egg experiment. For this one, before you soak the egg in vinegar, you blow out the egg like you are going to decorate an Easter egg. This time, the egg will be empty when it soaks.
What You Need:
- Straight Pin or Tack
- Tall Glass
Use a stright pin or a tack to poke a small hole in both ends of raw a egg. Hold the egg over the sink and blow on one end of the egg so that the yolk and egg white drain out the hole on the other side. Once the egg is empty soak the remaining egg shell in vinegar for a week. How does the egg look when you are done soaking it? Hold the egg in your hand and fold it in half. Now let go. What does the egg do? Toss the folded egg gently back and forth between your two hands. Now what does it do?
The vinegar dissolvs the hard shell of the egg. What you have left is the soft inner membrane of the egg. It LOOKS hard and still has an egg shape but it is soft, that’s why you can fold it. When you gently toss the egg back and forth btween your hands air enters through the two holes at either end of the egg. The egg blows back up, just like a balloon.
Here are some books websites that will help you understands acids and how they behave and the strange example of the folding eggshell:
- Chem4Kids: Acids and Bases
- BBC KS3 Bitsize: Acids and Bases and Metals
- Steve Spangler Science: How to Make a Folding Egg
- Weird Science Kids: Folding Egg
- Google Preview: Naked Eggs and Flying Potatoes (How to Make a Folding Egg page 89-91)
Words to Know:
Acid – A chemical that is often sour tasting and corrosive. It dissolves some things.
Dissolve – When a solid comes apart and spreads out into a liquid…like kool aid in water.
Calcium - One of the most common minerals found in animals bodies. It makes up bones, teeth, and eggshells.
Absorb – To soak up…like a sponge in water.