1. 1 TAKS Objective 5 Energy and Heat It Is All Around You…

2. 2 Heat transfers in three ways: Conduction Convection Radiation

3. 3Conduction Ouch! …is the transfer of heat by the direct contact of particles of matter. The heat of the boiling liquid directly contacts the metal spoon and causes the spoon to transfer the heat to the hand.

4. 4 Air above the flame heats and expands and you feel the heat transferring into your hand. Cool water is pushed down As the heated water rises… Convection …is the transfer of heat by the actual motion of a fluid (liquid or gas) in the form of currents. The heated water rises as the cooler water is pushed down. The water that was pushed down is then heated and … then rises pushing the now cooler water down. This causes a current in the water.

5. 5 ConvectionConvection link

6. 6 Convection Currents Hot liquids and gases expand and rise while the cooler liquid or gas falls 1. Hot air rises 2. Goes across 3. Then down 4. And across

7. 7Radiation …is heat transfer by electromagnetic waves. MATTER is not necessary for this transfer of heat. A common type of radiation comes from the sun. Examples include – Ultraviolet Visible Light Color spectrum – (ROYGBIV) Infrared

8. 8 Radiation

9. 9 Heat_Transfer.asf

10. 10 Lets Identify Types of Heat Transfer Using your slate write down if the following pictures represent: Conduction Convection, or Radiation

11. 11 Picture One

12. 12 Picture Two

13. 13 Picture Three

14. 14 Picture Four

15. 15 Picture Five

16. 16 Now identify the next five pictures on your handout independently.

17. TAKS OBJECTIVE 5 Energy Sources 17

18. 18 Energy Sources Energy sources are considered to be renewable or nonrenewable. A renewable resource is a resource that can be replenished in a short period of time (ex. Solar, wind, water, geothermal, biomass) A nonrenewable resource is a natural resource that cannot be replenished (re-made or re-grown) as quickly as it is used (ex. Nuclear energy and fossil fuels such as coal, oil, natural gas)

19. Energy Resources have their advantages and disadvantages 19

20. 20 Fossil fuels are fuels formed by natural resources in the geological past from the remains of once living organisms.

21. 21 Disadvantages of Fossil Fuels As earth reserves of nonrenewable fossil fuels decrease, they become harder to obtain and more expensive Burning them harms our environment (particles in smoke cause breathing problems) Burning carbon containing fuels produces CO 2 that may contribute to Global warming. Advantages of Fossil Fuels Used to generate almost 70% of electricity such as Petroleum, oil, natural gas, and coal.

22. 22 Nuclear Energy Is energy created from the energy locked up in atoms. When an atom is split (nuclear fission) into smaller fragments, energy is released.

23. 23 Advantages of Nuclear Energy It doesn’t produce air pollution and CO 2 Nuclear fuel is inexpensive and easy to transport

24. 24 Disadvantages of Nuclear Energy They produce large amounts of excess heat, which can harm fish and other animals in nearby lakes and streams. Nuclear accidents have the potential to cause radiation sickness and take human lives. Produces waste that remain hazardous for thousands of years. Only produce 20% of U.S. electricity today in nuclear power plants.

25. 25 Solar Energy a renewable resource in which the electromagnetic radiation from the sun can be converted to electricity by the use of solar cells and photoelectric cells

26. 26 Advantages of Solar Energy It is replaced nearly as quickly as it is used. The sun’s radiant energy can be used to heat homes and provide hot water. Solar energy is nonpolluting. Photovoltaic cells convert solar energy to electricity, which powers calculators.

27. 27 Disadvantages of Solar Energy Converting solar energy to electricity is only 15-20% efficient. The conversion cost more money.

28. 28 Batteries Batteries convert chemical energy to electrical energy.

29. 29 Advantages of Batteries Rechargeable batteries are more environmentally friendly than disposable ones. Disadvantages of Batteries Manufacturing batteries require large amounts of energy. Larger batteries pose environmental hazards because they contain heavy metals such as lead.

30. 30 Energy from Wind and Water (Hydro) Advantages Wind energy can be useful in areas with high and consistent winds Both Hydroelectric and wind energy are renewable and nonpolluting.

31. 31 Energy from Wind and Water Disadvantages Wind energy is inconsistent Pose danger to birds from turning of blades Requires a lot of land Hydroelectric power plants generate only about 4% of U.S. electricity today. Artificial dams are not possible in many areas. Dams may disrupt fish migration and other aspects of natural ecosystems.

32. 32 Geothermal Energy is thermal energy contained deep in the Earth. Advantages: geothermal power plants are about 80% efficient in converting geothermal energy to electricity. it is a clean process that does not cause pollution only uses a small amount of land and doesn’t disrupt the ecosystems Disadvantages: this process is only feasible where magma is close to the Earth’s surface such as Iceland. very expensive to drill deep into the earth to capture the geothermal energy