In fact, get two eggs, one boiled and the other raw, and spin them rapidly on their sides on a mirror or other perfectly smooth surface. If you put the palm of your hand gently upon the boiled egg while it is spinning, it, of course, ceases to move, and remains motionless after you have lifted your hand. But if you do the same with a raw egg, it will immediately begin to spin again when the hand is removed. Indeed, it is extraordinary how long you can hold your hand upon it without destroying its motion. The reason of this is no doubt apparent. The fluid within the egg continues to revolve, though the shell is stationary, while in the other case the whole egg is stopped. If you attempt to spin the eggs on the mirror like a top, you will find that the boiled egg will spin for a considerable time, but the other will fall almost immediately on its side.
A great demonstration of dynamics, and much safer than the tennis ball in the car experiment we did in college. However, when I tried it the eggs wobbled off the glass onto the floor.