Cool Spinning Eggs Science Experiment | Inertia Demo Here's a cool trick..Ask your friends to tell the difference between a hard-boiled egg and a raw egg, obviously ..without cracking them! Sounds pretty easy...trust me it is not. Unless you know the trick and you understand the concept of inertia!! For this experiment you'll need: • Two plates • Hard-boiled egg • Uncooked or a raw egg Before you start this experiment, see if you can decide which egg is the raw one and which egg is the hard boiled one. Hard to find?? Now try this: • Place these two eggs on the different two plates. • Start them spinning at the same time. • Notice that one egg would spin perfectly, while the other one wobbles slightly. • Now try touching these eggs while they are spinning. • Observe that one of them would completely stop spinning while the other would stop temporarily, but then continue spinning again. • The egg that spins longer is the raw egg. EXPLANATION: The raw eggs continues to spin because when the egg is stopped with fingers, the fact is that only the egg shell stops spinning but the liquid contents inside the egg keep spinning thereby making the egg spin again. This force that makes the egg contents which are already spinning to continue spinning is called inertia. Inertia is the tendency of body to remain at rest or continue to be in motion unless it is acted upon by a greater external force. This is the reason why you need to just touch the egg to stop it. If you literally hold it, it might stop completely as that would mean that you are applying a greater external force on it when it is spinning. Just touching the raw egg to stop it would not be a force great enough to stop it completely. When you touch the spinning boiled egg, it stops almost immediately because the contents inside it are solid, that is, the egg white and yolk fused together. Hence it cannot continue to spin.