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