1. Electricity and Conserving Resources
State Objectives 2.d. and 4.d.

2. What is Electricity?
Electricity is a form of energy produced by the flow of electrons from one point to another.
Current electricity is a continuous flow of electricity or the amount of a charge that moves past a certain point each second
SI unit for current is the ampere or amp

3. DC versus AC Current
DC current is when the electrical charge moves in one direction
Ex. Batteries
Always flow from the negative terminal to the positive terminal.
AC current is when the electrical charge flows in one direction, then in the reverse direction over and over again
Ex. Electrical current from the power plant to your home

4. Controlling a Current
Voltage: the measure of how much electrical potential energy each electron can gain (push)
Standard Unit: Volts
Resistance: the measure of how difficult it is for electrons to flow through a material (friction)
– Standard unit: Ohms
Insulators have a higher resistance than conductors.

5. Currents Flow In Circuits
An electric circuit is a complete path for the flow of electricity
Open circuits have a break in the path
Closed circuits have no breaks in the path

6. Generating Electricity
Generators are devices that spin a coiled wire within a magnetic field to produce electricity
The mechanical energy of a spinning turbine is transformed into electrical energy for human use.
Primary method for producing the electricity in homes, schools, & the community.

7. What Spins the Turbine?
Energy is produced by burning fossil fuels to boil water produces steam that turns a turbine to generate electricity.
Burning fossil fuels causes a large amount of pollution

8. Coal Power Plant

9. Power Grids
A power grid is a transmission network that connects power plants to multiple substations near a populated area.
Allows distant energy sources (such as hydroelectric power plants) to be connected to consumers in population centers

10. The U.S. Power Grid

11. Substations
A substation is a part of an electrical distribution system that switches, changes, or regulates electric voltage.
transform voltage from high to low, or the reverse.
A substation that has a step-up transformer increases the voltage while decreasing the current.
A substation that has a step-down transformer decreases the voltage while increasing the current for domestic and commercial distribution.

12. Substation

13. Transmission Lines
Transmission lines carry electricity from power plants to distribution systems that power commercial and domestic consumers.

14. Transmission Lines

15. Transformers
Device that transfers electrical energy from one circuit to another & changes the voltage by increasing or decreasing it.
Helps monitor the operation of the power grid and measures current.

16. Transformers

17. Path of Electricity through a Power Grid
Power Plant
Substation ( there are several along the way)
Transmission Lines ( high & low voltage)
Transformer (lowers voltage before entering the home)
Junction Box on the home (brings it into the home)
Outlet (sends it to electrical devices)
Electric circuit for a blow dryer

18. Power Grid

19. Resources for Energy
State Objective 4.d.

20. What are Resources?
Natural resources are the parts of the environment that are useful or necessary for the survival of living organisms.

21. Two Types of Resources
Renewable resources are resources that are constantly being recycled or replaced by nature. For example, sunlight, water, and air.

22. Renewable Resources

23. Two Types of Resources
Nonrenewable resources are resources that are used up more quickly than they are replaced.
Ex. Minerals, metals, & fossil fuels

24. Nonrenewable Resources

25. Energy Use
Most energy used by humans comes from fossil fuels.

26. Fossil Fuels
Made of hydrocarbons, compounds that contain carbon and hydrogen atoms.
Combustion is the process of burning fossil fuels to release energy.
Carbon dioxide and water are two other products of combustion.

27. Coal
Coal is a sedimentary rock formed from dead plant matter that is buried underwater
Most is used for electrical power plants.

28. Petroleum (Oil)
Petroleum (oil) is a mineral made from the remains of dead marine organisms buried in Earth’s crust.
Provides one-third of world’s energy.
Can be turned into gasoline, diesel fuel, paints, and plastics.

29. Natural Gas
Natural gas is a colorless, odorless gas made mostly of methane
Made mostly of methane but contains other gases.
Often found with oil deposits.

30. Alternative Energy Sources
Why is it important that we find alternatives to fossil fuels? Give at least three reasons.

31. Alternative Energy Sources
Hydroelectric power is produced when falling water is used to turn the turbine in an electric generator. No pollution is produced but building dams can damage habitats.

32. Hydroelectric Power

33. Pickwick Dam

34. Alternative Energy Sources
Wind power generates electricity by using windmills to turn the blades of a generator.

35. Alternative Energy Sources
Nuclear energy is released when the nuclei of uranium atoms are split apart.
Energy is used to produce steam to turn the blades of a generator.
Does not produce air pollution but does produce radioactive wastes.

36. Nuclear Power

37. Alternative Energy Sources
Geothermal energy is heat energy contained in Earth’s crust.
Used to produce steam to generate electricity.

38. Geothermal Energy

39. Alternative Energy Sources
Biomass is a renewable energy source made from living or recently living organisms.
Examples include garbage, wood, wastes, landfill gases.

40. Biomass

41. Alternative Energy Sources
Solar energy is the leading alternative to fossil fuels because it is inexhaustible and produces no pollution.
Very expensive.
Photovoltaic cells are devices that convert light energy into electric energy.

42. Solar Panels

43. Human Effect on the Environment
Pollution

44. Pollution
A pollutant is any substance that contaminates the environment.
Examples of air pollutants include smoke, ash, carbon monoxide, and carbon dioxide.

45. Greenhouse Effect
The greenhouse effect is the natural trapping of the Sun’s heat by the Earth’s atmosphere. Gases that contribute to the greenhouse effect include water vapor, carbon dioxide, and methane.

46. Greenhouse Effect

47. Global Warming
As more CO2 is added, the atmosphere traps more heat, causing global warming.

48. Effects of Global Warming
It changes rainfall patterns.
It may increase the amount of storms and hurricanes.
It could cause the polar ice caps to melt.

49. Global Warming
Sea-level rise is an increase in sea level that may be caused by global warming.

51. Ozone Depletion
The ozone layer of the atmosphere absorbs harmful ultraviolet (UV) radiation from the Sun.
Ozone depletion is the thinning of the ozone layer.
Allows more UV radiation to reach Earth and could cause an increase in skin cancer.

52. CFCs

54. Effects of Overpopulation
inadequate freshwater
depletion of natural resources
increased pollution
loss of biodiversity or entire ecosystems
global warming
mass extinctions

55. Conserving Resources & the Environment
How Can We Help?
Conserving Resources & the Environment

56. Ways to Conserve Energy
1. Turn off lights when not in use.

57. Ways to Conserve Energy
2. Car pool or use public transportation.

58. Ways to Conserve Energy
3. Walk or ride a bicycle.

59. Ways to Conserve Energy
4. Use energy efficient appliances and bulbs.

60. Ways to Conserve Energy
5. Research new ways to depend more on alternate energy sources.