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