Stretch Band Demonstration

[12 piece bucket]

And posted a while back . . . This may be relevant to our discussion too.

http://theserver.theschool.columbia....s_pulleys.html

Check this out for more on Pulley stuff.

5. Decreasing Pulley Speed

Main Idea: If you use a small pulley wheel to drive a large pulley wheel, the large one will turn slower.

Additional Information: With this model, we have a pulley with a small driver wheel and a large follower wheel. It's really hard to make a wheel like the big one turn - it would take a lot of force. But with a smaller wheel, we can use a process called gearing down to help. Gearing down decreases speed but increases force. Since it's easy to turn a small wheel at a fast speed, we use it to move the large one. A small driver wheel makes a large follower wheel turn more slowly. Since this is a pulley model, both wheels turn in the same direction.

8. Gearing Up

Main Idea: If you use a large gear to drive a small gear, the small one will turn faster.

Additional Information: Here we see a large driver gear and a small follower. We can move the small gear pretty fast on our own, but we can use a process called gearing up to move it even faster. Gearing up increases speed, but decreases force. A good example of a gearing-up system in real life is a 10-speed bike - when you shift into 10th gear, you turn a large gear with the pedals, which drives a small gear attached to the rear wheel. For this model, one turn of the 24-tooth driver produce three turns of the 8-tooth follower. This ratio of 1:3 is called the gearing up ratio

10. Increasing Pulley Speed

Main Idea: If you use a large pulley wheel to drive a small pulley wheel, the small one will turn faster.

Additional Information: In this pulley model we have a large driver wheel and a small follower. We can move the small wheel pretty fast on our own, but these pulleys use a process called gearing up to move it even faster. Gearing up increases speed, but decreases force. A large driver wheel makes a small follower wheel turn faster. However, unlike gears, in this pulley model both wheels turn in the same direction.

This was built with Lego's. I reckon you could raid junior's box and build you some different pulleys to see what happens. Also . . . if the belt is crossed up. The wheels move in opposite directions.