See-Through Egg Science

What You Do:

1. Carefully place the whole, uncooked egg in the glass jar. Use a big spoon if necessary.
2. Pour vinegar over the egg so that it is completely submersed in the vinegar.
3. Cover the jar and observe. Discuss with your child: what is happening inside the jar? What can she see? (She should see bubbles forming.) What does she think might be happening?
4. Explain to your child that the bubbles she sees in the jar tell you that the vinegar is dissolving the eggshell. It’s eating away at the “stuff” (calcium, mostly) that makes egg shells hard. Ask her what she thinks might happen if you let the vinegar keep eating away at the eggshell.
5. Place the jar inside the refrigerator for about 24 hours. Take it out of the fridge, and use a baster to remove most of the vinegar. (Be careful not to poke or bump the egg! Remember, its shell has been dissolving.) Then pour fresh vinegar over the egg, and return to the refrigerator for another 24 hours.
6. Continue in this manner until the eggshell becomes see-through. (The amount of time needed to achieve this varies with the size, variety, and thickness of the eggshell.) 
7. Gently use a large spoon to scoop out the egg. Now you have an egg without a shell! You can see the insides of the egg, which are being held inside by a membrane. Explain that the membrane is like a skin around the egg.  Ask your child to consider why this membrane might be helpful to a growing chick inside its egg. (It keeps out dirt and germs and other harmful substances. It also lets air get in.)
8. Encourage your child to observe the shell-less egg and describe what she sees. Can she name any other parts of the egg? (Yolk, egg white or albumen, etc.) 
9. Finally, let your child hold the egg in her hand over a sink and give a very gentle squeeze. (Watch out!  If you squeeze too hard, the egg will explode!) What does it feel like? (It feels like a squishy pillow.) Discuss why the insides of the egg would be a perfect place for a baby chick to grow before it hatches. (It’s squishy, so it’s like a cushion for the growing chick, and the membrane and shell keep it safe.)