?
WHAT’S HAPPENING
The teeth of the gear wheels mesh together
and transfer the movement up to the leaf.
The faster you turn the handle, the faster
the leaf turns too. If you turn the handle
the other way, then the leaf turns the
other way too. If you watch the large
gear wheel, it’s easy to see that the
wheels always turn in the opposite
directions.
5
4
5
Try swapping the large and small gear wheels
on the tree trunk.
?
WHAT’S HAPPENING
If the teeth of the gear wheels mesh together, then your gear mechanism is working. Turn the
axle behind the large gear wheel at the same speed as before and watch the leaf. Does it still
turn just as fast? Or slower? The small gear wheel has 16 teeth altogether, and the large
gear wheel has 24. The ratio of the number of teeth on the small gear wheel to the number
of teeth on the large gear wheel is 2 to 3 (2 x 8 = 16, 3 x 8 =24). That means that when you
turn the small gear wheel three times, the large one will have turned twice. Look at the
two drawings above and decide which setup makes the leaf turn faster. Then try it out!
You can connect the pulley wheels, gear
wheels, rubber band, and crank handl
e
in many different ways, and transfer the
motion differently. Try it out!
Tip!
3 turns
3 turns
How many times does
the large wheel turn?
How many times does
the large wheel turn?
19
Rain Shield
