Editing Angular Momentum Chair (section)

===Short Explanation===

Momentum is when something with mass has a velocity to it. A simple example of this is walking across the floor; when walking at a constant pace, you have momentum. Angular momentum is when you have a mass with velocity, but it is either spinning or moving on a curve. an example would be the feeling you get when you are in a car that goes quickly around a turn. You have momentum while in the car, and when it is turning that momentum is angled. So, you feel what you might think of as a "pull" away from the inside of the turn. This is because momentum is conserved, meaning that it stays at the same amount at all times.

When the volunteer was spinning with the weights held out, the weights had angular momentum to them, and we can think of them drawing a big circle around the volunteer. When they pulled the weights in, the weights now made a smaller circle. If they stayed spinning at the same initial rate, then the weights would be moving much slower in that smaller circle, which would mean that they lost momentum. So in order for momentum to be conserved, the chair started spinning faster! This is true for the opposite as well: When they move the weights outward, they start making a big circle again, so momentum is conserved by them slowing down.

The wheel also uses this idea. When the wheel is spinning vertically, it has momentum along that vertical line. When they turn the wheel sideways, it loses some momentum while changing to the horizontal line, and that momentum goes into the volunteer. Since they are sitting on the stool, the stool will start to spin! The direction they spin in is related to the direction that the wheel is spinning. This means that, if you took the wheel, turned it around, and gave it back, that they would then spin in the opposite direction when they turn it!