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electricity.pptx
- 2. •A form ofenergy from movement of electrons. •Comes from the Greek word “electron” ELECTRICITY
- 3. ELECTRICITY •It is associatedwith electric charge, a property of subatomic particles. •Charges can be stationary or moving.
- 4.
- 5. STATIC ELECTRICITY •The temporary buildingup of charge on an object •Some atoms hold electrons more tightly than others.
- 6. STATIC ELECTRICITY •Charging by conductionhappens when a charged object touches another object and electrons are transferred
- 7. STATIC ELECTRICITY • Chargingby induction happens when a charged object and is held close to another object and that causes charges to be rearranged
- 8. STATIC ELECTRICITY •Charging by frictionhappens when objects rub together and electrons are transferred.
- 9. Insulators and Conductors •Some materials allow charges to be transferred (conductor) while others do not (insulator)
- 10. Insulators and Conductors •Conductors:Gold,Silver,Copper,Iron,Lead ,Salt and Water. • Insulators: Plastics,Glass,Dry air, and Wood
- 11. Electric Current •Flow ofcharges •The electric charge in a current is carried by minute particles called electrons.
- 12. Electric Current •For electricity toflow, you need a closed continuous path, called circuit
- 13. Current • The measureof how many electrons per second. • Also called amperage • Measured in amperes
- 14. Current •AC is anelectric current that regularly reverses direction Alternating Current (AC)
- 15. • DC isan electric current that flows in only one direction and has a fairly constant average value Direct Current (DC) Current
- 19. • In addition,for electrons to flow there must be a potential difference between two places Remember: Electric potential energy- two unlike charges Lower potential energy Higher potential energy
- 20. Lower potential High potential electrons Direction of flow •Electrical pressure • Charges flow from high voltage to low voltage or from high PE to low PE Voltage
- 24. • Cells cancause voltage that makes electrons flow • There are two kinds electrochemical cells, wet cells such as battery and cells like flashlight Electrochemical Cell
- 25. • When twoor more cells are connected together we call this a battery Electrochemical Cell
- 26. • The cellschemical energy is used up pushing a current round a circuit. Current is Direct Current Electrochemical Cell
- 27. • Allesandro Volta(1800) cell Electrochemical Cell
- 28. • Wet Cell= Car Battery Electrochemical Cell
- 29. • Dry Cell= Household “Battery” Electrochemical Cell
- 30. • What occursin a wire when the circuit switch is closed? Electrochemical Cell
- 31. • The tendencyfor a material to oppose the flow of electrons • Different materials have different amounts of resistance to the flow of electrons. • The unit of resistance is ohm (Ω) Resistance
- 32. • Resistance inwires produces a loss of energy (usually in the form of heat), so materials with no resistance produce no energy loss when current pass Resistance
- 33. • Thin wiresprovide more resistance than do thick wires Which materials has higher resistance?
- 34. • Insulators havehigh resistance Which materials has higher resistance?
- 35. • Resistance also dependson temperature, usually increasing as the temperature increases resistance Which materials has higher resistance?
- 36. • To makethe circuit, these components are connected together with metal connecting wires CIRCUITS switch Cell wires lamp
- 37. • To makethe circuit, these components are connected together with metal connecting wires CIRCUITS switch Cell wires lamp • When the switch is turned on (open), the lamp lights up. This is because there is a continuous path of metal for the electric current to flow around.
- 38. CIRCUITS • Scientist usuallydraw electric circuits using symbols. Cell lamp Switch Wires
- 39.
- 40. TYPES OF CIRCUIT SERIESPARALLEL