Spinning Eggs

What you need:

  • a hard boiled egg
  • a raw egg
  • a hard surface

What to do:

  1. Spin the hard boiled egg. Then spin the raw egg.
  2. Notice the speed at which they spin and which one stops first.
  3. Spin the hard boiled egg – once it is moving, touch it to make it stop spinning.
  4. Now spin the raw egg – once it is moving, touch it to make it stop. What happens?

https://youtu.be/FBvSafhoV8k

What happens:

The hard boiled egg spins for much longer (and faster) than the raw egg. This is because the inside is solid, so the entire thing is one solid mass. The raw egg has liquid on the inside, which is not attached to the shell. The liquid inside it much harder to spin, and it slows the egg down much faster. However, when you stop the spinning eggs, the hard boiled egg will stop instantly. The raw egg will stop, but then will start spinning again on its own. This is because the insides don’t stop spinning once the shell is stopped, so it makes the entire thing start spinning again (though it doesn’t last long!).

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