Applications of electromagnets
I can describe how electromagnets are used in a range of practical applications.
Applications of electromagnets
I can describe how electromagnets are used in a range of practical applications.
Lesson details
Key learning points
- An electromagnetic door lock uses an electromagnet to pull a magnetic bolt to unlock a door.
- An electric bell often contains an electromagnet that attracts and moves the striker, making it hit the bell.
- As an electromagnet moves the striker in an electric bell, it breaks its own circuit to let the striker spring back.
- A motor contains a spinning coil of wire that is an electromagnet.
- When there is a current in the spinning coil of wire in a motor, other magnets around it will push it round.
Keywords
Electromagnet - A magnet made by running current through a coil of wire round an iron core.
Temporary magnet - An electromagnet that loses its magnetism when current stops flowing through it.
Electric lock - A lock that can be opened with an electromagnet when a switch is closed.
Electric bell - A bell that uses an electromagnet to strike a clapper on the bell and which resets itself to keep ringing.
Electric motor - A motor that uses a magnetic field to produce a force.
Common misconception
It is very common for pupils to think that uninsulated wire is needed for the coil of an electromagnet.
When discussing an electromagnet, always refer to the insulated wire in its core, which is necessary so the current in each turn adds to the strength of the electromagnet.
Equipment
Insulated wire, AAA battery, 2 safety pins, insulating tape, neodymium magnet and sandpaper.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
Loading...
Prior knowledge starter quiz
6 Questions
Q1.A single loop of wire in a coil is also called a __________.
Q2.A piece of unmagnetised steel would be attracted to __________ of an electromagnet.
Q3.Some magnetic materials are described as ‘soft’. Which of the following statements about a soft magnetic material is correct?
Q4.An electromagnet is made by winding a wire around a soft iron core. Which of the following is necessary for the electromagnet to work?
Q5.A coil of wire carries a current of 0.5 A. Which of the following changes would increase the strength of the magnetic field around the wire?
Q6.An electromagnet with a pure iron core is used to pick up small pieces of steel. Which of the following statements explain why some pieces stay stuck to the electromagnet after it is switched off?
Assessment exit quiz
6 Questions
Q1.A magnet that never loses its magnetism is called a permanent magnet. An electromagnet that loses its magnetism when current stops flowing is called a magnet.
Q2.The diagram shows an electric bell. Match each label with the name of the part.
switch
bell
electromagnet
clapper
armature
Q3.The diagram shows an electric bell. Which of the following statements are correct?
Q4.The diagram shows an electric bell. A person holds the switch down. Which of the following statements are correct?
Q5.The diagram shows an electromagnetic door lock. Which of the following statements are correct?
