In this tutorial, we learn how to turn eggs into bouncing balls. You will need: hard boiled eggs, vinegar, and a jar to make these. First, fill your jar up with vinegar and then drop your egg inside of it. After this, let the egg sit inside of the jar for a couple of days. After this, take the egg out and peel the membrane of off the outside of it. Now, you will be able to use your egg to bounce off of anything. When peeled apart, the contents of the egg will be rubbery as well! This is an interesting experiment and great to teach kids.