Finding out about gears
Materials
cardboard box
corrugated packing paper
marker
pins (3 long)
plastic lids (1 small,
2 large)
• white glue
What special things can gears do? Here is a project that will help you
find out.
Cut three strips of paper long enough to go around the lids. The strips
should be % inch (2 centimeters) wide. Glue one strip around each lid.
Mark an arrow on each lid, as shown. Push a pin through the center of
each lid.
Which way?
Put the two big gears on the box. Point the arrows in the same
direction. Fit the teeth together. Push the pins into the box. What
happens when you turn one gear?
The second gear moves in the opposite direction. It always turns the
other way.
Left, right, left
Make a chain of three gears. Turn the first one. What happens to the
other gears?
The first gear makes the second gear turn the opposite way. And the
second gear makes the third gear turn the same way as the first gear.
Around and around
Put the two big gears on the box, with both arrows pointing in the same
direction. Turn one gear around exactly once. How far does it make the
other gear turn? How fast does it make the gear move?
Now use a big gear and a small gear. Turn the big gear once. How far and
how fast does it make the small gear turn? What happens if you turn the
small gear once?
When two gears are the same size, both gears turn at the same speed.
When a big gear turns a small gear, the small gear turns faster. And
when a small gear turns a big gear, the big gear moves more slowly.
