Electromagnets

Electromagnets

And Their Uses

Learning Intentions and Success Criteria

• Learning Intentions:

• Students will know that certain materials can be magnetised by electric current.

• Success Criteria:

• Students will be able to explain how electromagnets work and identify some of the
uses of electromagnets.

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Electromagnets

This Photo by Unknown Author is licensed under CC BY-SA-NC

​•An electromagnet is a coil of wire wrapped around an iron core.

•When an electric current is passed through the coil, the iron is magnetised.

•When the current is turned off, the iron is no longer magnetised.

•Being able to turn a magnet on and off at will can be very useful.

Labelling

Label the parts of the electromagnet

Drag labels to their correct position on the image

Magnetised paper clips

Wire coil wrapped around an iron core

Power source

Multiple Select

What are two ways you can make an electromagnet stronger (increase the magnetic fore)

• Replace the iron core with wood

• Increase the number of coils (more wraps of wire)

• Switch off the current (the power)

• Increase the current and or Voltage supply (use a larger batter or turn up the power.)

Uses of Electromagnets

• Electromagnets are also used in:

• doorbells

• metal detectors

• speakers

• phones

• electric motors and generators.

​This electromagnet is attached to a giant crane


When the electric current is switched on, the iron or steel in the scrap is attracted to the electromagnet and lifted to a container.


The electric current is switched off and the metal falls into the container.

Labelling

Label the forces acting on the scrap metal

Drag labels to their correct position on the image

Gravity

Electromagnetism

​The next slide is a simulation

Move the compas around the
magnet

Notice that the needle aligns with the direction of the magnetic field

The magnetic field always faces from north to South - because like poles repel and the red side of the compas in the North pole

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​On the next slide click on the electromagnet button in the blue ribbon at the top

The parts that make up the electromagnet are a battery, and a coil of wire

When electric current passes through the wire coil, it creates a magnetic field, just like a bar magnet

**Increase and decrease the voltage to see the effects on the strength of the magnetic field

*Notice that the compas needle aligns with the direction of the magnetic field and

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