World’s Oldest Toy?
What would you say if I asked you what you think the world’s oldest toy is? You're right, it's the spinning top! Believe it or not, the oldest top ever found was dated to be about six thousand years old and there was a wooden top found in King Tut's tomb! The beauty of these toys is in their simplicity. You've got a well-balanced, vaguely pointy thing. You spin it and it stands up, easy peasy R.H.Fleetzy! All it takes is a little angular momentum and you're set.
What is angular momentum?
That part is not quite so easy peasy. Have you ever been riding in a car and when it turns left, you feel your body kind of shift to the right? That’s inertia keeping you moving along the path you were originally on. Newton's first law tells us that if an object is going in a straight line, it's gonna keep going in that straight line unless something else makes it stop going in that same straight line. Your body and the car together are both going straight at first, but the car changes direction. Your body inside the car wants to keep going forward and the car turning stops that from happening. Newton's second law tells us about how when objects in motion meet, their mass and their speed are what defines which object is going to change direction. Both you and the car are going the same speed, but since the car has much more mass than you, instead of you dragging the car forward in the straight line you were going, the car pushes you along the curved path it wants to go. And, it keeps pushing you like this until you're both going straight again.
Spinning tops are a little tricky, you can think of them as constantly going around that turn as long as the top is spinning. Once in motion, every single bit of that top wants to be going in a straight line but it is constantly pulled around in a circle by the fact that every other part of the top wants to go in an ever-changing, slightly different-angled, straight line. If your top is heavy enough, and if it is spinning fast enough, then the top's momentum is great enough to overcome gravity pulling the top down on the table. As the top slows down, it loses more and more of that momentum until gravity ultimately wins.
We have a great video that shows you how you can build your own top to explore angular momentum yourself. Check it out here along with all of our other awesome FLEETtv videos!