Electricity

1. Electricity Chapter 7 Section 1 Electric Charge

2. Sections • 1. Electric Charge slides 3 - 35 • 2. Electric Current slides 36 - 67 • 3. Electrical Energy slides 68 - 96

3. Electric Charge • The center of an atom is made of protons (+) and neutrons (no charge).

4. Electric Charge • The center of an atom is made of protons (+) and neutrons (no charge). • Electrons (-) move around the center of the atom.

5. Electric Charge • The amount of + Charge on a proton = The amount of – Charge on an electron.

6. Electric Charge • The amount of + Charge on a proton = The amount of – Charge on an electron. • Each atom has the same number of protons & electrons making them electrically neutral.

7. Electricity • Atoms have no charge.

8. Electricity • Atoms have no charge. • - ion if it gains electrons

9. Electricity • Atoms have no charge. • - ion if it gains electrons • + ion if it loses electrons

10. Electricity • Atoms have no charge. • - ion if it gains electrons • + ion if it loses electrons • Electrons can move from atom to atom or from object to object.

11. Static Electricity • Is the buildup of charges on an object.

12. Static Electricity • Is the buildup of charges on an object. • When there is static electricity, the electric charges are not balanced.

13. Static Electricity • Is the buildup of charges on an object. • When there is static electricity, the electric charges are not balanced. • The Law of Conservation of charge states that charge can be transferred from object to object but it cannot be created or destroyed.

14. Opposite charges attract Like charges repel Electricity + - + + - -

15. Electricity • The electric force between charged objects depends on how far apart they are.

16. Electricity • The electric force between charged objects depends on how far apart they are. • The force decreases the farther apart the charges are.

17. Electricity • The electric force between charged objects depends on how far apart they are. • The force decreases the farther apart the charges are. • The electric force also depends upon the amount of charge on the objects.

18. Electricity • The electric force between charged objects depends on how far apart they are. • The force decreases the farther apart the charges are. • The electric force also depends upon the amount of charge on the objects. • More charge = More force

19. Electric Field • Area around every electric charge that exerts a force. • Movement of a positive charge in electric fields. + -

20. Electric & Gravitational Force • Electric forces are stronger than gravity.

21. Electric & Gravitational Force • Electric forces are stronger than gravity. • Atoms are held together by electric forces.

22. Electric & Gravitational Force • Electric forces are stronger than gravity. • Atoms are held together by electric forces. • These forces cause chemical bonds to make a new substance.

23. Electric & Gravitational Force • Electric forces are stronger than gravity. • Atoms are held together by electric forces. • These forces cause chemical bonds to make a new substance. • Electric forces between atoms are greater than the gravitational forces between atoms.

24. Electric & Gravitational Force • Electric forces are stronger than gravity. • Atoms are held together by electric forces. • These forces cause chemical bonds to make a new substance. • Electric forces between atoms are greater than the gravitational forces between atoms. • Electric forces between most objects are less than the gravitational forces between them because most objects are elec. neutral.

25. Conductors & Insulators • Electrons move more easily in conductors.

26. Conductors & Insulators • Electrons move more easily in conductors. Ex. Metals such as copper • Insulators do not allow electrons to move as easily.Ex. Plastic, wood rubber and glass

27. Charging Objects • Charging by contact- transferring charges by touching or rubbing ex. Clothes in a dryer

28. Charging Objects • Charging by contact- transferring charges by touching or rubbing ex. Clothes in a dryer • Charging by induction- charged object rearranges the electrons on a nearby neutral object.

29. Lightning • Large static discharge between clouds and the ground that causes atoms & molecules to light up.

30. Lightning • Large static discharge between clouds and the ground that causes atoms & molecules to light up. • Thunder- Electric energy in a lightning bolt rips electrons off atoms in the air causing great amounts of heat, up to 25,000 °C.

31. Lightning • Large static discharge between clouds and the ground that causes atoms & molecules to light up. • Thunder- Electric energy in a lightning bolt rips electrons off atoms in the air causing great amounts of heat, up to 25,000 °C. • The heat makes the air around the lightning bolt move faster creating sound waves.

32. Grounding • Grounding avoids damage by providing a path for electric charge to move to earth.

33. Electroscope • Can detect when an object has an electric charge. <http://paginas.terra.com.br/saude/feijoshp/chispas/electroscope1.gif>

34. Electroscope • Can detect when an object has an electric charge. • The metal rod is a conductor.

35. Electroscope • Can detect when an object has an electric charge. • The metal rod is a conductor. • When the leaves have a charge they repel each other and spread apart.

36. Electric Current Chp 7 Section 2

37. Electric Current • The net movement of electric charges in one direction.

38. Electric Current • The net movement of electric charges in one direction. • Measured in units called amperes or amps.

39. Electric Current • The net movement of electric charges in one direction. • Measured in units called amperes or amps. • Symbol for amperes is A.

40. Electric Current • The net movement of electric charges in one direction. • Measured in units called amperes or amps. • Symbol for amperes is A. • Measures the electrons that flow past one point.

41. Electric Current • The net movement of electric charges in one direction. • Measured in units called amperes or amps. • Symbol for amperes is A. • Measures the electrons that flow past one point. • 1 A = 6,250 million billion electrons moving past a point every second.

42. Voltage • The electric force that makes charges move.

43. Voltage • The electric force that makes charges move. • Voltage is like the force that acts on water in a pipe.

44. Voltage • The electric force that makes charges move. • Voltage is like the force that acts on water in a pipe. • Water flows from higher pressure to lower; likewise, electric charge flows from higher voltage to lower voltage.

45. Voltage difference • Related to the force that makes electric charges flow.

46. Voltage difference • Related to the force that makes electric charges flow. • Measured in units called volts (V).

47. Electric Circuit • Closed loop-like path that current must follow. <www.energyquest.ca.gov>

48. Electric Circuit • Closed loop-like path that current must follow. • If the circuit is broken, current will not flow & bulb will not light.

49. Batteries • Provide the voltage difference that keeps electric current flowing in a circuit.

50. Batteries • Provide the voltage difference that keeps electric current flowing in a circuit. • The positive & negative ends are called terminals.