1. Electricity from Magnetism When you use an electric appliance or turn on a light in your home, you probably don’t think about where the energy comes from.When you use an electric appliance or turn on a light in your home, you probably don’t think about where the energy comes from. How does a magneticHow does a magnetic field produce electric field produce electric current? current?

2. Electricity from Magnetism In 1831 Michael Faraday was able to generate an electric current from a magnetic field.In 1831 Michael Faraday was able to generate an electric current from a magnetic field.

3. Electricity from Magnetism When a bar magnet is thrust into a coil connected to an electric circuit, a current is caused to flow in the circuit to which the coil is attached. If the magnet is withdrawn, the direction of the current is reversed. Such currents are called INDUCED CURRENTSWhen a bar magnet is thrust into a coil connected to an electric circuit, a current is caused to flow in the circuit to which the coil is attached. If the magnet is withdrawn, the direction of the current is reversed. Such currents are called INDUCED CURRENTS

4. Electricity from Magnetism The size of the current depends on how fast the magnet moves in or out of the coil, and the number of loops in the coil.The size of the current depends on how fast the magnet moves in or out of the coil, and the number of loops in the coil. The phenomenon of inducing a current by changing the magnetic field in a coil of wire is known as ELECTROMAGNETIC INDUCTION.The phenomenon of inducing a current by changing the magnetic field in a coil of wire is known as ELECTROMAGNETIC INDUCTION.

5. Electricity from Magnetism Faraday showed that the magnetic field around a wire can be changed by moving either the magnet in and out of a coil of wire OR by moving a wire between the poles of a magnet.Faraday showed that the magnetic field around a wire can be changed by moving either the magnet in and out of a coil of wire OR by moving a wire between the poles of a magnet.

6. Electricity from Magnetism A generator is a device that uses electromagnetic induction to convert kinetic energy into electrical energy.A generator is a device that uses electromagnetic induction to convert kinetic energy into electrical energy.

7. Electricity from Magnetism The electric current produced by the generator changes direction each time the coil makes a half-turn. Because the electric current continually changes direction, the electric current is an alternating current.The electric current produced by the generator changes direction each time the coil makes a half-turn. Because the electric current continually changes direction, the electric current is an alternating current.

8. Electricity from Magnetism Another device that relies on electromagnetic induction is a transformer.Another device that relies on electromagnetic induction is a transformer. A transformer increases or decreases the voltage of an alternating current.A transformer increases or decreases the voltage of an alternating current. A simple transformer consists of two coils of wire wrapped around an iron ring.A simple transformer consists of two coils of wire wrapped around an iron ring.

9. Electricity from Magnetism In hydroelectric plants, water flowing downhill turns a turbine. The turbine turns the magnet of a generator, inducing electric current.In hydroelectric plants, water flowing downhill turns a turbine. The turbine turns the magnet of a generator, inducing electric current.

10. Electricity from Magnetism In nuclear power plants, thermal energy createdIn nuclear power plants, thermal energy created by a nuclear reaction boils by a nuclear reaction boils water to produce steam which turns water to produce steam which turns a turbine. a turbine.

11. Electricity from Magnetism The electric current that provides your home with electrical energy is usually transformed 3 times before it reaches your home.The electric current that provides your home with electrical energy is usually transformed 3 times before it reaches your home.

12. Electricity from Magnetism 1. The power plant produces electric current with high voltage. To decrease the loss of power over long distance transmission, step-up transformers increase the voltage thousands of times!

13. Electricity from Magnetism 2. The electricity travels over transmission lines with very high voltage to a distribution station with a step-down transformer that lowers the voltage.

14. Electricity from Magnetism 3. The electric current travels over local power lines to another step-down transformer which lowers the voltage again before the current reaches your house.