Activity #2: Gear Speed and Torque

This activity will allow the student to experiment with different gears and distinguish between gearing that produces speed and that which creates a good amount of torque. Reducing the number of revolutions is called gear reduction (high torque). Increasing the number of revolutions is called gearing up (high speed). Students will learn to differentiate the two conditions.

Materials: 8t (t = tooth), 16t, 24t, 40t LEGO gears, four LEGO axles, one 11 hole LEGO support beam.

Procedure (Part 1):

1. Put an axle through the middle of any gear and put it on the gearblock. Do the same for a different gear and put it on the gearblock so that their teeth mesh.
2. When you turn one gear clockwise, which way does the other gear go?
3. What happens if you add more gears?
4. Put an axle through the largest gear and put it on the gearblock. Do the same for the smallest gear and, again, put them on the gearblock so that their teeth mesh.
5. With one hand, turn the axle for the large gear and watch the small gear spin. Is it going fast or slow?
6. Now twirl the axle of the small gear and watch the big gear go around. Is it going fast or slow?
7. While you're still turning the small gear, try to stop the big gear by pinching its axle. Is it easier or harder to stop (high torque or low torque)?