1. Magnetism from Electricity
Unit 11
Section 2

2. I. Electromagnetism
Electromagnetism is the interaction between electricity and magnetism.
An electric current produces a magnetic field, but it is not very strong.
c. Two devices are used to strengthen the magnetic field made by an electric current (charges traveling through a wire)
solenoids
electromagnets

3. II. Solenoids
A solenoid is a coil of wire with an electric current in it.
To strengthen the magnetic field of a solenoid you can:
Increase the loops per meter that are used.
Increase the current (amount of charges) in the wire by adding another energy source (battery).
Soleniod

4. III. Electromagnets
An electromagnet is made up of a solenoid wrapped around an iron core.
When an electric current is present in the solenoid (coils), the electromagnet acts as a magnet.
Solenoids and electromagnets have a magnetic field only when there is an electric current in it.
iron core
solenoid

5. IV. Increasing the Strength of Electromagnets
There are 3 ways to increase the strength of an electromagnet:
1. Add a bigger energy source (battery)
2. Increase the amount of coils
3. Add an iron core

6. V. Applications of Electromagnetism
Electromagnets can be used in doorbells and electric motors.
Electric motors can be found in washing machines, power windows and your computers hard drive.

7. VI. Electric Motors
An electric motor is a device that changes electrical energy into mechanical energy.
Electric motors have an armature, or a loop of wire that can rotate.
They also have a commutator that causes the electric current in the coil to change directions.
The commutator is what keeps the armature rotating.

8. VII. Differences Between Bar Magnets and Electromagnets
Electromagnets can be turned off.
The polarity (poles) on an electromagnet can be switched.
You can increase/decrease the strength of an electromagnet

9. Quickie Quiz True or false?
Electromagnetism is the interaction between electricity and magnetism.

10. Quickie Quiz
TRUE
Electromagnetism is the interaction between electricity and magnetism.

11. Quickie Quiz Which of the following are ways To
increase the power of a solenoid? (could
be more than one)
Increase loops of coil
Increase the size of the iron core
Increase the current in the wire.
Increase the amount of magnets

12. Quickie Quiz
Which of the following are ways to increase the power of a solenoid? (could be more than one)
Increase loops of coil
Increase the size of the iron core
Increase the current in the wire.
Increase the amount of magnets

13. Quickie Quiz Which is NOT part of an electromagnet? Wire Battery
Compass
Magnet

14. Quickie Quiz Which is NOT part of an electromagnet? Wire Battery
Compass
Magnet

15. Quickie Quiz
An _________________ changes electrical energy into mechanical energy.
Magnet
Electromagnet
Compass
Electric Motor

16. Quickie Quiz
An _________________ changes electrical energy into mechanical energy.
Magnet
Electromagnet
Compass
Electric Motor