YOU WILL NEED
- Boil two eggs in water for ten minutes until they are hardboiled.
- Cool the eggs under running water, then chill them in the refrigerator.
- Put several raw eggs into a bowl with the boiled ones. Ask a friend to sort the cooked eggs from the raw ones—without cracking them! Can't do it?
- Show your friend how: Spin each egg on its side one at a time. Let the egg spin for a moment, then stop it and immediately release it. The raw eggs start to spin again (just a little), but the cooked ones don't.
The raw egg starts to spin again because it has liquid yolk and egg white inside. Even when you stop the egg from spinning, the liquid inside keeps turning because it is not attached to the shell.
Text by Julie Vosburgh Agnone
Illustration by David Bamundo