Welcome Back Minions

1. Welcome Back Minions Place books on floor. Have only notebook and writing utensil on the desk.

2. Preview… • How is an electric current produced? • How are conductors different from insulators? • What causes electric charges to flow in a circuit? • How does resistance affect current?

3. Flow of Electric Charges • Static Electricity • Electric charges do not flow continuously. • When electric charges that are made to flow through a wire (or similar material) produces an electric current. • Electric Current • The continuous flow of electric charges through a material.

4. Flow of Electric Charges • Andre Marie Ampere • Early investigator of electricity • Unit for the rate of current is named after him. • Ampere, shortened to “Amp” or “A”. • The number of amps describes the amount of charge flowing past a given point each second.

5. Flow of Electric Charges • To produce electric current, charges must flow continuously from one place to another. • Electric Circuit • A complete, unbroken path through which electric charges can flow.

6. Conductors and Insulators • What makes a conductor? • What makes an insulator?

7. Conductors and Insulators • Conductor • A material where a charge flows freely • Metals such as silver, copper, aluminum, and iron • Water • Insulator • A material which charges cannot flow freely • Rubber, glass, sand, plastic, and wood

8. Conductor or Insulator!!! • Eraser • Metal Pen

9. Conductor or Insulator!!! • Paper Clip • Paper Envelope

10. Conductor or Insulator!!! • Nails • Nails

11. Conductor or Insulator!!! • Pencils • Coins

12. Voltage • Sounds familiar… where have we heard that before? • Batteries • Appliances at home • Voltage Source • Battery or Power Plant • Light Bulb • Voltage Rating • (Must have this much to light!)

13. Voltage • The measure of energy given to the charge flowing in a circuit. • The greater the voltage, the greater the force or “pressure” that drives the charge through the circuit.

14. Amps and Voltage… • Difference between Amps and Volts • Think of a water hose… • Amps measure how much water comes out of a hose. • Volts measure how hard the water comes out of a hose.

15. Voltage • An electric circuit requires something to maintain a voltage.

16. Voltage • Voltage Source • A device that creates a potential difference in an electric circuit. • Ex. Batteries & Generators • Has two terminals. • The voltage between the terminals causes charges to move around the circuit.

17. Resistance • Current depends on Resistance • Resistance • The measure of how difficult it is for charges to flow through a material. • Thickness of wire • Length of Wire

18. Resistance • Resistance is measured in the unit called the ohm. “Ω” • Named after George Ohm, German Physicist who investigated resistance.

19. Review • How is an electric current produced? 1) It depends on the length and thickness of a wire. 2) Charges must flow continuously from one point to another. 3) By taking an insulated wire and forming a loop. 4) Simply flipping a switch.

20. Review • How are conductors different from insulators? 1) Electric currents flow easily through insulators while it cannot flow easily through conductors. 2) Resistors work with insulators but conductors do not. 3) Conductors have a positive charge while insulators have a negative charge. 4) Electric currents flow easily through conductors while it cannot flow easily through insulators.

21. Review • What causes electric charges to flow in a circuit? 1) Voltage 2) Ohms 3) Conductors 4) Static Electricity

22. Review • How does resistance affect current? 1) Lesser the resistance, the bigger need for power. 2) Lesser the resistance, the less current there is for the voltage. 3) Greater the resistance, the less current there is for the voltage. 4) Greater the resistance, the more current there is for the voltage.