How to Make a Simple Machine for 2nd Grade
Pulleys, levers, wedges and inclined planes are all examples of simple machines that can be used to reduce work. Building a simple machine is a great way for a 2nd grade class to learn about how these machines work and how they can be useful. The following steps describe how to build a simple pulley and observe how it can lift more weight with less force.
Things You'll Need
- Desk
- Small rectangular board at least 12"x6"x1" clamp or vise
- Two pulleys
- Screw-in hook
- Small bucket
- Large bucket
- Rope (about 3' long)
- Stones (enough to fill the small bucket)
- 20 weights
- S-hook
Instructions
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1
Provide enough materials for students to build their own pulley systems in pairs or small groups. Before the lesson, attach a pulley to one end of the boards, and a hook to the other side. The pulley and hook should be next to each other on the same end of the board.
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2
Clamp the board to the edge of a desk with the clamp or vise. The pulley and hook should extend off the edge of the desk, facing down.
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3
Fill the small bucket with stones and tie the rope to the small bucket's handle. Put the small bucket on the floor and run the rope over the top of the board. Tie the large bucket to the other end of the rope. The large bucket should be hanging about halfway between the board and the floor.
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4
Start adding weights into the large bucket until the small bucket just lifts off the floor. Record the number of weights it took to do this.
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5
Remove the weights from the large bucket. Run the rope through the pulley. Put the small bucket on the floor and leave the large bucket hanging halfway between the board and the floor.
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6
Repeat Step 4. It should require fewer weights to lift the bucket this time.
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7
Remove the weights from the large bucket. Untie the rope from the small bucket and run the second pulley through the rope. Attach the small bucket to the pulley with the S-hook and tie the loose end of the rope to the hook attached to the board. The small bucket should be on the floor and the large bucket about halfway between the floor and the board.
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8
Repeat Step 4. It will require even fewer weights to lift the bucket with two pulleys.
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Tips & Warnings
Discuss the results with the students. Which way is the easiest to lift a heavy load? Ask them to think of ways that pulleys can help people do work, or ways they have seen pulleys being used to reduce work.
References
Resources
- Photo Credit Image courtesy of Wikipedia Commons
