We will need:
- 2 eggs,
- smooth surface.
- Boil one of the eggs;
- Let cool;
- Give both eggs to the restless kid, and ask him/her witch one is boiled;
- Ask your child to spin both eggs on the smooth surface.
One of the eggs spin continuously, the other one oscillates randomly.
The egg spinning continuously is the boiled egg, the other one is the raw.
The boiled egg is solid, the raw is liquid.When you spin the raw egg the liquid spins inside, but takes a few seconds to overcome the inertia and therefore the movement is not continuous.
The boiled egg is solid and therefore the inside moves with the shell.
This is Newton First Law of Movement:
"All bodies remain in their state of rest or uniform rectilinear motion, unless they are forced to change its state by influence of external forces"
In simpler terms, the Newton's First Law says: "If something is moving or stopped, will remain in motion or stopped unless something disturbs the system."
You can do another test:
Spin the raw egg, when the egg is spinning continuously place your finger on top of it, to stop it, and take it fast. You will see that the raw egg still moving after you stop the shell... why? Because the liquid inside remains in motion.
Newton in action!Enjoy!