ECS - Grade 4

10 minutes

1. fresh egg
2. hard-boiled egg

Take turns spinning each egg on a table top. One will spin easily, and the other will spin in wobbles. Label each, then crack them open to see which is which. Discuss why this happens.

The yolk and the white in the uncooked egg are still quite fluid and will slosh around when the egg spins. The sloshing changes the center of gravity inside the egg and makes it wobble. The contents of the hard-boiled egg are no longer fluid, so they don't move around inside the egg, and the egg spins smoothly.