Energy systems
ElectroCity
7. Vibrators and Noisemakers
Overview
Students first explore how to create a vibrating device, by making a motor turn an unbalanced wheel. Then they create a noisemaker, by attaching a flap to a wheel, and forcing it to hit an obstacle each time it rotates.
Advance Preparation
- Make a motor circuit, as in Lesson 4, and add a bushing and wheel.
- Make a vibrator by taping a penny or other small weight near the outside of the wheel
- Make a noisemaker by taping a flap to the wheel and letting it hit a hard surface.
- Photocopy worksheet and assessment (downloadable at bottom of page).
- Post a sheet of chart paper labeled Things that Vibrate.
Procedure
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What makes something vibrate? Lead a class discussion about things that vibrate. List them on the chart. To get the discussion started, you might ask;
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What makes a washing machine vibrate.
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When a cellphone is in “vibrate” mode, what do you think is going on inside?
Develop the idea that whenever something is rotating, it will also vibrate if more weight is on one side than on the other. For example, a washing machine vibrates when the wash is piled up on one side of the basket. A cell phone has a little motor inside, with an off-center weight that vibrates when the motor is turned on.
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Make a vibrator:
Demonstrate the vibrator you have made. Ask for ideas about what could be used as weights. Then distribute materials and provide time for students to make their own vibrators.
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Noisemakers:
Ask the class: How could I use this same motor to make a noise? Develop the idea that if the wheel is hitting something, or making another object hit something, there will be a noise. Demonstrate how to attach a rubber band or flap of cardstock to the wheel, and challenge students to create their own noisemakers.
Worksheet: Noisemakers and Vibrators
Assessment
Troubleshooting
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To make the vibrations stronger, try:
- Using a heavier weight (see video)
- Moving the weight further from the center (see video).
- If the motor won’t turn, it may not be powerful enough to overcome the resistance of the flap
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Noisemakers:
- To make the sound louder (see video), try using a stiffer flap or making the flap hit a harder surface
- To make a deeper tone (see video), try making the flap hit the bottom of a box.