4. Motors
Wed, 04/06/2011 - 01:11 — gbenenson
1. What is a motor? Lead a discussion about what motors do and where you can find them. If students mention car motors, explain that you are looking for motors that run because of electricity. These kinds of motors use energy from electricity to make something move, such as the blades of an electric pencil sharpener, the tub of a washing machine or the air pulled in by a vacuum cleaner. Post examples on chart paper. The energy that comes from a motor is the energy of motion, which is called kinetic energy.
2. Making a motor run: Provide each student with a AA battery and a motor. Challenge them to get the motor to turn. Students can use the worksheet to record what they did and what they discovered. Show the symbol for a motor, and encourage them to use it on the worksheet.
3. Is a motor polar? Review what it means for a device to be polar: it matters which way it is connected. For example, if a LED is attached to a battery the wrong way, it will not work. Review the directions in which something can rotate: clockwise vs. counterclockwise. To find out which way the motor rotates, suggest that they attach a small piece of tape to the shaft. Which way does the motor go? How can you make it turn the other way? See a video exploring direction of motion of a motor.
4. Turning a wheel: Provide bushings and wheels, and demonstrate how to attach a wheel snugly to a motor by using a bushing. Offer tape and craft materials for attahing to the wheels. Provide time for student to experiment and record their findings on the Worksheet.
5. Make a battery holder: Students will probably want their circuits to work reliably, without their having to touch wires to battery terminals. Demonstrate how to make a simple battery holder.
6. Add a switch: Review the purpose of a switch, types of switches and ways of making at least one type. Ask each student to make a switch, add it to the motor circuit, and demonstrate how to control a motor using a switch. They should use the standard circuit symbols to represent their new circuits. See videos and diagrams showing how to add a switch to a circuit.
Click on any of the items below to see a video about the issue:
Overview
In this lesson, students begin by exploring motors: what they do, how to get one to work, change its direction and control it with a switch.Advance Preparation
- Make a sample battery holder (see a diagram and video)
- Photocopy worksheet and assessment sheet (downloadable from bottom of page)
- Post a sheet of chart paper to list examples of motors and where they are found
- Post the circuit symbol for a motor
Materials
- Motors and AA batteries -- one of each per student
- Bushings and wheels to attach to motors
- Craft materials for attaching to motors and wheels
- Materials for making battery holders and switches: cardstock, paper fasteners, paper clips, mini-binder clips, tape
- Worksheet: Motors
- Sample battery holder (see Advance preparation)
Procedure
1. What is a motor? Lead a discussion about what motors do and where you can find them. If students mention car motors, explain that you are looking for motors that run because of electricity. These kinds of motors use energy from electricity to make something move, such as the blades of an electric pencil sharpener, the tub of a washing machine or the air pulled in by a vacuum cleaner. Post examples on chart paper. The energy that comes from a motor is the energy of motion, which is called kinetic energy.
2. Making a motor run: Provide each student with a AA battery and a motor. Challenge them to get the motor to turn. Students can use the worksheet to record what they did and what they discovered. Show the symbol for a motor, and encourage them to use it on the worksheet.
3. Is a motor polar? Review what it means for a device to be polar: it matters which way it is connected. For example, if a LED is attached to a battery the wrong way, it will not work. Review the directions in which something can rotate: clockwise vs. counterclockwise. To find out which way the motor rotates, suggest that they attach a small piece of tape to the shaft. Which way does the motor go? How can you make it turn the other way? See a video exploring direction of motion of a motor.
4. Turning a wheel: Provide bushings and wheels, and demonstrate how to attach a wheel snugly to a motor by using a bushing. Offer tape and craft materials for attahing to the wheels. Provide time for student to experiment and record their findings on the Worksheet.
5. Make a battery holder: Students will probably want their circuits to work reliably, without their having to touch wires to battery terminals. Demonstrate how to make a simple battery holder.
6. Add a switch: Review the purpose of a switch, types of switches and ways of making at least one type. Ask each student to make a switch, add it to the motor circuit, and demonstrate how to control a motor using a switch. They should use the standard circuit symbols to represent their new circuits. See videos and diagrams showing how to add a switch to a circuit.
Troubleshooting
Click on any of the items below to see a video about the issue:
- Can't connect a wire because plastic insulation gets in the way
- Can't get a bushing off a motor
- Can't turn the motor off, except by disconnecting the wires
- When switch is open, motor turns on, and vice versa; battery gets hot
- The connection to the battery is bad,
- The connection to the switch is bad, or
- The motor itself is bad.