Presentation on theme: "Section 5. The purpose We they are going to read about changing magnetic energy to electrical energy and learn how magnetism is changed to electricity."— Presentation transcript:
The purpose We they are going to read about changing magnetic energy to electrical energy and learn how magnetism is changed to electricity.
Give examples of how you use electricity Where does electricity comes from?
Quick Summary Magnetism can be used to generate electricity. Changing a magnetic field creates an electric current. Most electricity comes from generators.
Questions What are two ways to increase the amount of electric current produced by a magnet? What is a significant difference between the dynamo that Faraday invented and a modern generator? How does the number of coiled loops affect the strength of the current? What happens when a magnet is moved back and forth inside a coiled wire? How many years after Joseph Henry discovered that changing a magnetic field generates an electric current did Michael Faraday make the same discovery?
Quick Summary The history of electricity began in about the year 600 B.C. A generator may be powered by wind energy, falling water, steam or nuclear energy. Generators that use the "hot dry rock" method have a system of pipes that pumps water deep underground where hot rocks heat it into steam that is then pumped out. It is important to observe safety rules when using electricity.
Questions What are the 4 R's of electrical safety? What are some common electric items that must be used carefully? What do you think will be the next important discovery or invention about electricity? How do magnets help generators produce electricity? Wind turbines today generate electricity much better than they did about 25 years ago. In 1981, a wind turbine produced 25 kilowatts of electrical power. A modern turbine can create up to 750 kilowatts of electricity. How many times more powerful is a modern wind turbine?
Geysers Deep below Earth's surface, water comes in contact with very hot rocks. The rocks heat the water. The heat escapes to the surface in hot, high- pressured steam. These hot bursts of underground water are called geysers. Geothermal electric plants use this steam to turn generators. As generators turn, electricity is produced.