Sect 17.3
- 1. 6 th Grade Science Chapter 17 Energy and Resources Notes Section 17.3
- 2. Where does our energy come from? Nearly all the energy used today can be traced to the sun. What are fossil fuels? Fossil fuels are coal, oil and natural gas. Key Questions 1
- 3. Energy Resources The surface of Earth receives energy from two sources—the Sun and radioactive atoms in Earth’s interior. Nearly all the energy you used today can be traced to the Sun, even the gasoline used to power the car or school bus you came to school in.
- 5. Coal, oil, and natural gas are fossil fuels. Fossil fuels are a nonrenewable resource because we are using the resource much faster than it is being replaced.
- 6. Fossil Fuels Coal was formed by similar process from the remains of ancient plants that once lived on land.
- 7. Using Fossil Fuels Burning fossil fuels to produce energy also generates chemical compounds that cause pollution. Each year billions of kilograms of air pollutants are produced by burning fossil fuels. These pollutants can cause respiratory illness and acid rain.
- 8. Nuclear Energy To obtain electrical energy from nuclear energy, a series of energy transformations must occur.
- 9. What is a nonrenewable resource? A nonrenewable resource is an energy source that is used up much faster than it can be replaced. What is a renewable resource? A renewable resource is an energy source that is replenished continually. Key Questions 2 The Tadpole Galaxy
- 10. Hydroelectricity Currently, transforming the potential energy of water that is trapped behind dams supplies the world with almost 20 percent of its electrical energy.
- 11. Solar Energy The Sun is the origin of almost all the energy that is used on Earth. Because the Sun will go on producing an enormous amount of energy for billions of years, the Sun is an inexhaustible source of energy. An inexhaustible resource is an energy source that can’t be used up by humans.
- 12. What are examples of alternative resources? Examples of alternative resources are solar energy, wind, and geothermal energy. What is a inexhaustible resource? An inexhaustible resource is an energy source that can’t be used up by humans. Key Questions 3 The Sombrero Galaxy
- 13. Wind Modern windmills convert the kinetic energy of the wind to electrical energy. The propeller is connected to a generator so that electrical energy is generated when wind spins the propeller. Some disadvantages are that windmills produce noise and that large areas of land are needed.
- 15. Wind power designs old and new.
- 16. Using Tidal Energy As the tide comes in, it turns a turbine connected to a generator. When high tide occurs, gates are closed that trap water behind a dam.
- 17. What is a photovoltaic collector? A photovoltaic collector is a device that transforms radiant energy directly into electrical energy. What is geothermal energy? Geothermal energy is heat energy generated inside the Earth. Key Questions 4
- 18. Collecting the Sun’s Energy A photovoltaic is a device that transforms radiant energy directly into electrical energy. Photovoltaics are used to power calculators and satellites, including the International Space Station .
- 20. Geothermal Energy At some places deep within Earth the temperature is hot enough to melt rock. This molten rock, or magma, can rise up and close to the surface through cracks in the crust. In other places, magma gets close to the surface and heats the rock around it.
- 22. Conserving Energy One way to make the supply of fossil fuels last longer is to use less energy. Reducing the use of energy is called conserving energy.
- 23. Diagram the energy conversions that occur when coal is formed, and then burned to produce thermal energy. Explain why solar energy is considered an inexhaustible source of energy. Explain how a heat pump is used to both heat and cool a building. Identify advantages and disadvantages of using fossil fuels, hydroelectricity and solar energy as energy sources. Questions Section 17.3