Understanding Forces and Motion - Activities

NC Standard:  4.07

Activity:  Pulley Power

Question: How do people use simple machines to solve problems?

Vocabulary: pulley, load

Background: Pulleys are a special sort of wheel. A pulley wheel has a groove all for a rope to fit into. If you attach one end of the rope to a heavy load you can lift it easier using a pulley system.

Materials:
2 broom handles
a length of rope
5 people

Procedure:

• 1.  Tie one end of the rope to one of the broom handles near the bristles.
• 2.  Thread the rope in a zig zag pattern between the two broom handles.
• 3.  Have two students hold each broom handle about two feet apart. Broom handles should be horizontal to the floor about waist high.
• 4.  The fifth student holds the loose end of the rope.
• 5.  Students holding the broom handle should try to keep the handles two feet apart as the 5th student pulls on the rope to try to bring the broom handles closer together.

Note:  The 5th student will easily beat the pulling power of the other 4 students because you have created a pulley system that makes the work easier for the 5th student. Dust the handles with talcum powder before you begin the activity. This will reduce the friction and make it even easier to pull the broom handles together.

Prediction:

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Observations:

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Conclusions:
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Line of Learning:  This line is drawn to provide students with a space to share their experimental learning in words or pictures.
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