# 8 Experiments to Teach Electromagnetism

Use these free STEM lessons and activities to teach about electromagnetism.

Independently, electricity and magnetism are both powerful concepts in physics. Electromagnetism is the study of how electricity and magnetism can work together, and electromagnetism is one approach to generating electricity.

Teaching students about electromagnetism helps them synthesize what they know about magnets and electricity to see how they can work together. The resources below enable hands-on exploration of electromagnetism, electric motors, and electric generators. These experiments are closely related to experiments that teach about electricity, but in these activities, magnetic fields play an important role in converting electrical energy into mechanical energy or generating electric current.

The free STEM lessons and activities below cover permanent and temporary magnets, electromagnets, ferromagnetic materials, magnetic fields, and alternating and direct current. In these activities, students will learn about the Lorentz force, Faraday's law of magnetic induction, the parts of a motor or a generator, Newton's third law of motion, homopolar motors, and the role open and closed circuits play in electromagnetic devices.

The resources below to teach about electromagnetism have been grouped as follows:

Note: Science Buddies Lesson Plans contain materials to support educators leading hands-on STEM learning with students. Lesson Plans offer NGSS alignment, contain background materials to boost teacher confidence, even in areas that may be new to them, and include supplemental resources like worksheets, videos, discussion questions, and assessment materials. Activities are simplified explorations that can be used in the classroom or in informal learning environments. Student projects that appear below contain experiments that can be effectively adapted for use by educators for teaching about the topic.

## Lesson Plans and Activities to Teach About Electromagnetism

1. ### 1. Strength of an Electromagnet

In the What Factors Affect the Strength of an Electromagnet? lesson, students make simple electromagnets each using a battery, wire, and a nail (a classic experiment!), and then explore how different variables may affect the strength of an electromagnet. For example, using a ferromagnetic core may result in a stronger electromagnetic field. As they experiment to see how many paper clips their electromagnet can pick up, they can easily see and assess the impact of changing different variables. Questions: How do you turn an electromagnet on and off? What flows through an electromagnet when it is on? What are some of the variables that can affect the strength of an electromagnet?

Note: The convenient Strength of an Electromagnet Kit can be used to demonstrate this lesson.
2. ### 2. Make a Paper Speaker

In the Build a Paper Speaker activity, students make a speaker using paper, magnets, and a coil of wire as part of a circuit that plugs into an audio (or mobile) device. The audio device sends electrical signals to the coil of wire, which turns it into a temporary magnet that pushes on the permanent neodymium magnets and causes the speaker to vibrate. This vibration generates sound waves that travel through the air to our ears. Constructing the stack of magnets surrounded by the coil of wire that doesn't touch the magnets gives students a good visual look at how the magnetic field works to create the electromagnet in the speaker. As an extension to this experiment, students can explore the paper speaker further in the Measure the Frequency Response of a Paper Speaker project. Question: Will adding more permanent magnets make the sound from the speaker louder?

1. ### 3. A Homopolar Motor

In the How to Make a Homopolar Motor activity, students make a simple homopolar motor using a battery, a magnet, and a piece of wire. This creates a closed circuit when the wire touches both the battery and the magnet (that is touching the bottom of the battery). The electrical current that flows through the wire interacts with the magnet's magnetic field, resulting in a force that pushes on the wire and causes it to spin around the battery. This force is called the Lorentz force. The spinning of this simple electric motor converts electrical energy into mechanical energy. Know the terms! The motor is described as "homopolar" because the polarity of the electrical current and magnetic field does not change. Questions: What about a magnet allows it to push and pull on other magnets or metal objects without touching them? Why does the motor not work if the wire touches only the battery and not also the magnet?

How to Make a Homopolar Motor - Science Experiment

2. ### 4. Build a Simple Motor

In the Build a Simple Electric Motor! project, students make a simple motor that is similar to the homopolar motor described above but uses a permanent magnet and electromagnet in a different configuration. Once the motor is created, the wire coil will spin about the axle of the motor. By experimenting with the size of the coil, students can examine the relationship between the strength of the electromagnetic field, the number of loops in the coil, and the speed at which the motor spins. Questions: What does Fleming's left-hand rule for motors help predict? What is the difference between a permanent and a temporary magnet?

Build a Simple Electric Motor

3. ### 5. Use a Reed Switch

In the Build a Reed Switch Motor project, students build a simple direct current (DC) motor using an electromagnet and a reed switch and then experiment to explore the effect of voltage on motor speed. The voltage in a DC motor doesn't alternate with time (the way alternating current (AC) does). The key parts of the DC motor are an electromagnet, a rotating shaft that has permanent magnets attached to it, and a reed switch. The reed switch closes the circuit when the permanent magnet is nearby. This turns the electromagnet on. When the permanent magnet rotates away from the reed switch, the switch opens, which shuts off current to the electromagnet. Questions: Why is the reed switch an important part of this motor? How does the reed switch make it so that the current continues to flow at the same rate? What is the relationship between voltage and how fast the motor spins?

### Electric Generators

An electric generator reverses the process used by an electric motor and converts mechanical energy into electrical energy. (A motor converts electrical energy into mechanical energy.) These experiments involve making and testing an electric generator.

1. ### 6. Shake Up Some Energy!

In the Human-Powered Energy project, students build a small generator that is "human-powered," meaning the generator creates electricity when you shake it. This kind of alternative energy is sustainable and is used, for example, in some flashlights. You shake them when you need to power them on. Once assembled, students can experiment with the generator by using it to light LEDs on a breadboard. Adding more LEDs requires more electricity, which requires students to explore ways to increase the amount of electricity created by the generator. Questions: How does "shaking" the generator result in the creation of electricity? Does using more magnets allow you to light up more LEDs? What is the relationship between the electromagnetic field and the number of LEDs that can be lit? Why are explorations of human-powered energy important? What is magnetic induction? Why does the generator create alternating current (AC)?

Note: This experiment has been developed for use with the Shaking Up Some Energy Kit.
2. ### 7. Coils and Generators

In the Shed Light on Electric Generators: Do More Coils Generate More Electricity? project, students build a more sophisticated electric generator than the human-powered one mentioned above and experiment to see how the amount of coiled wire affects the amount of electricity that is produced. The generator produces alternating current (AC), and electricity is only generated when the magnet is moving away from or toward the coil. Exploring ways to test the generator by creating consistent rotation of the shaft is part of the experiment. Question: What happens if you add a second coil to the generator?

3. ### 8. Improving Generator Output

In the Power Move: Manipulating Magnets to Improve Generator Output project, students expand their exploration and testing of a homemade electric generator to see how manipulating the magnets can improve the generator. After building the generator, students test with two different configurations of the permanent magnets. Questions: How does the configuration of permanent magnets affect when and how much electricity is generated? How can changes in the magnetic field help maximize the efficiency of the generator?

Note: Both of these projects are designed for use with the Electric Motor Generator Kit.

## Teaching About Electromagnetism in K-12

Exploring electromagnetism with students often centers around building and testing simple electromagnets, simple electric motors, and electric generators. These explorations involve both permanent and temporary magnets and help students see how magnetic fields can be used to create electric current.

Electric motors use a magnet's ability to attract and repel to create motion. Simple electromagnetic motors help students visualize the relationship between a magnet, its invisible magnetic field, and the objects it interacts with. A simple motor also reinforces the importance of closed circuits. After exploring simple motors, students can learn what happens when an electric motor runs in reverse as a generator.

Electrical current generates a magnetic field and creates an electromagnet, but a moving magnet can also generate electrical current in a closed loop of conducting wire. This effect, discovered by Michael Faraday and Joseph Henry, is called magnetic induction and is central to how electric generators work.

Note: There is crossover between teaching about electricity, circuits, magnetism, and electromagnetism. You can view teaching materials, experiments, and lessons for these topics in the following collections:

## Magnetism Tutorial

Magnetism and Electromagnetism Tutorial

The Electricity, Magnetism, & Electromagnetism Tutorial resource is a good place to start when introducing electromagnetism to students. For older students, the resource can be a helpful refresher. The video above offers an overview of magnets and electromagnets. (Tip! Google Classroom teachers can use the Google Classroom button to assign this resource to students.)

## Vocabulary

The following word bank contains words that may be covered when teaching about electromagnetism using the lessons and activities in this resource.

• Alternating current (AC)
• Ampere
• Coil
• Coulombs
• Current
• Direct current (DC)
• DC voltage
• Electric motor
• Electrical current
• Electrical energy
• Electricity
• Electromagnet
• Electromagnetic induction
• Electromagnetic spectrum
• Electron
• Faraday's law of magnetic induction
• Ferromagnetic
• Frequency
• Generator
• Hertz (Hz)
• Homopolar
• Kinetic energy
• Lorentz force
• Magnetic field
• Magnetic domain
• Magnetic induction
• Magnetism
• Neodymium magnet
• Newtons
• Newton's third law
• Permanent magnet
• Polarity
• Reed switch
• Right-hand rule
• Solenoid
• Tachometer
• Temporary magnet
• Teslas
• Voltage (volt)

## Thematic Collections

Collections like this help educators find themed activities in a specific subject area or discover activities and lessons that meet a curriculum need. We hope these collections make it convenient for teachers to browse related lessons and activities. For other collections, see the Teaching Science Units and Thematic Collections lists. We encourage you to browse the complete STEM Activities for Kids and Lesson Plans areas, too. Filters are available to help you narrow your search.

Development of this resource to support educators teaching K-12 STEM curriculum topics was made possible by generous support from the Donaldson Foundation.

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