How to Make a Pulley With Cardboard
A pulley changes the direction of a force. It's easy to make one out of cardboard and quite useful, especially for a science fair. Corrugated cardboard works best for this activity, since it's sturdy and thick. If you need your pulley to be thinner, try using a half-gallon milk carton instead. With a few other supplies you can find around the house, you'll have made one of the most ancient machines known to mankind.
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Things You'll Need
- Corrugated cardboard
- Pencil
- Glue
- Scissors or razor blade
- String
- Tape roll
- Ruler
Instructions
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1
Trace the circular shape of the tape roll on the cardboard with your pencil. This shape will be the size of your pulley. If you want a circle that's bigger or smaller than the tape roll, trace a different object. Bottles, cups, and jars work well. Choose the largest circular shape you have.
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2
Cut out the circular shape with the scissors or an art knife. This circle doesn't need to be perfectly round, so it's OK if there are rough edges.
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3
Trace the cardboard circle you just made onto another section of cardboard and cut out this second circle. These two cardboard circles will make the outer rims of the pulley.
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4
Trace another circle onto the cardboard using a smaller circular shape than you used before. This shape will be the groove over which the string is hung.
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5
Cut out the smaller circle from the cardboard. You should now have three circles: two that are equal and larger than the third.
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6
Draw a straight line across a circle, bisecting it. Draw another line perpendicular to the first. These two lines will meet at a point, which should be the center of the circle. Sharpen your pencil and poke it through the circle. Repeat this process for all three circles.
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7
Dab glue on the two larger circles and use them to sandwich the smaller circle in. The smaller circle will be glued inside the other two, larger circles. Make sure the hole you poked in the center of the circles line up, and wipe away any glue that seeps through it.
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8
Stick the pencil through the three glued holes of the pulley. This pencil is the axle for the pulley. Laying the string over the center circle, between the two larger circles, creates the pulley mechanism. Whatever you attach to the string will be supported by the pulley.
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References
- Photo Credit pulley of a boat image by timur1970 from Fotolia.com
