MOVEMENT ANALOGY

· GEARS

Gears are wheels with teeth around their edges. The teeth fit together so that when one gear turns, its teeth push against another gear’s teeth, causing it to turn as well. Gears that are next to each other rotate in opposite directions.

How do gears make life easier?

When a smaller gear drives a larger gear, the larger gear turns with more force. This is force magnification. Lower gears on a bike allow you to apply more force with each turn of the pedals, though you have to pedal more often! When a larger gear drives a smaller gear, the smaller gear completes its turns faster. The gears are magnifying a movement. When you turn the large gear in egg whisks, it causes smaller gears to spin four times as quickly. This is fast enough to turn egg whites into foam! When a series of gears are joined together, they can transfer motion energy across the whole series.

· PULLEYS

A pulley is a wheel that turns on an axle. An example of a pulley is a flagpole. Some amusement park rides are examples of pulleys. There are different types of pulleys such as a fixed pulley or a pulley that stays in the same place. With a fixed pulley, you change the direction of force, not the force needed. Then there’s a moveable pulley.