Basic Science 1: Electricity

• 1. Electricity BS-01 L1 L2 1

2. Charge and Circuit 2 3. What is Electricity We use the term electricity in many ways, but there are two things about electricity that we need to understand: Electric charge and Electric energy Electric charge is the stuff that flows through a resistance such as a wire, light bulb or motor. Electric charge flows through the resistance and around the wire, but charge is not used up, and charge is not created. Charge flows through a wire, but it can also sit in a wire or battery until the circuit is connected. Charges move through wires or conductors due to electric attraction and repulsion, but energy is required for charges to move through a wire. 3 4. Electric Energy 4 5. Electric Energy Electric energy, also called electromagnetic energy is the "stuff" that moves from place to place, and it always flows very fast (almost at the speed of light). Electric energy can be gained, lost, or changed from a wire or circuit, like a light bulb changing the flow of electrical energy into a flow of light and heat. 5 6. Magnets 6 7. Magnets A bar magnet has a field around it that we show as magnetic lines of force. Each magnet has a north pole and a south pole (opposite force). When two bar magnets are placed near each other, the strength of the magnetic field is very strong. Magnets are critical parts for making electricity. 7 8. Generator 8 9. Generator An electrical generator is a device that converts mechanical energy to electrical energy. If a wire cuts through a magnetic field, a small amount of electricity is induced into that wire. 9 10. Generator 10 11. Increasing Electricity If the wire is looped so that two wires cut the magnetic field, twice as much electricity is induced in that wire, three loops makes three times as much. The more loops, the more electricity is induced into the wire. If hundreds of looped wire cut that field, literally hundreds of times more electricity is induced in that wire. 11 12. Alternator 12 13. Alternator In present automobiles, electricity is created by an alternator that is a form of generator. You can see how many loops of wire are inside the housing of the alternator. There can be hundreds of feet of wire in a device like this. 13 14. Industrial Size Generator 14 15. Industrial Size Generator In an industrial generator, thousands of loops of a single wire are formed into a rotor. The rotor is attached to a shaft which is turned by some mechanical force. This mechanical force can be a steam turbine where the steam comes from burning natural gas or oil or coal. Steam could also come from a nuclear reactor where the heat of breaking atoms apart provides heat. In some parts of the country, water can turn those turbines in a dam. There can be miles of wire inside these giant generators made for Hoover dam. 15