Student Objective To explain how energy transformations produce electricity 1 Warm Up Predict: How EXACTLY does a generator produce electricity?

Energy Sources: What are pros & cons of different energy sources used to generate electricity? 2

3 Fossil Fuel Solar Power Wind Power Nuclear Cheap Concentrated source Can be built anywhere Easy to transport Renewable No pollution Land can still be used for farming Can be used in remote locations Renewable No pollution Radiant directly to electricity Can be used in remote locations Expensive Takes up lots of land Not always sunny Energy must be stored Non-renewable Pollution/global warming Dangerous to mine Few windy places Disrupts landscapes Disrupts bird migration noisy Harmful radiation Nuclear waste Relatively expensive (safety) Concentrated source No air pollution Reliable Cheap to make power

4 GALVANOMETER N S magnet coil cap What will happen when the magnet moves through the wire coil? (Notice there is NO battery in this setup.) Tests for electric current.

5 Spinning Magnet Coils

6 The moving magnet can push electrons in a wire. If the magnet or the coil keeps moving we get electricity. Mechanical energy makes electrical energy.

7 Generators In most generators, a source of mechanical energy turns huge turbines such as this one. The turbine is attached to the armature of a generator, which produces current.

8 AN AMAZING DISCOVERY BY HANS CHRISTIAN OERSTED happened IN 1820 when he was “playing” with a circuit and a compass. PREDICT: What do you think he discovered?

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11 H.C. Oersted’s Discovery conductor compass dry cell He discovered the electromagnet!

- What Is Electromagnetism? He discovered that: an electric current produces a magnetic field. He made the first electromagnet!

13 Copy this slide into your notes section showing his discovery. Electromagnet wire compass battery An electric current can create a magnetic field

- What Is Electromagnetism? The magnetic field produced by the solenoid electromagnet resembles that of a bar magnet.

- What Is Electromagnetism? Electromagnets Electromagnets are used to lift heavy objects. A switch is turned on in the crane so that a current is produced in the electromagnet.

Can you explain this? What is different here? When current flows the other way the poles switch. The nail attracts a different side of the compass needle.

17 Electricity, Magnetism, and Motion Electrical Energy and Motion When a wire with current is placed in a magnetic field, electrical energy is transformed into mechanical energy.

18 Electric Motors An electric motor transforms electrical energy into mechanical energy.

19 The generator is opposite of the motor !

20 MECHANICAL ENERGY ELECTRICAL ENERGY

21 MOTOR BOTH GENERATOR Name: Date: Class: magnets coils magnet coil Pg Pg