A super super easy experiment that you can do with two things you probably already have in your kitchen.  My kids liked it so much, as soon as they finished with the first one, they immediately started another.

1.  Take a raw egg, and place it in a cup.

2.  Cover it with vinegar.  We used apple cider vinegar the first time, and regular white vinegar the second time.  Both worked fine.

3.  Cover the cup (we used plastic wrap held on with a rubber band) and stick it in the fridge.  Check it every day and give it a swirl.    You can change out the vinegar too, if it gets too yucky.

After a few days, the shell is completely dissolved, and the egg is held together by nothing but its tough membrane:

It is still raw inside, but it is strong and rubbery.  You can even bounce it a bit on the counter (if you’re gentle)  It’s also very swollen, because with the shell gone, it absorbs much of the liquid it’s been sitting in.

For even more fun, stick it back in the cup with some food coloring and water, and let it sit overnight.

And for EXTRA fun, be sure to do what my kids did, and pop it with a fork to examine its insides when you’re done.