1. Electricity Vocabulary Negatively charged ion – Gains electrons Positively charged ion – Loses electrons

2. Charges Law of Electric Charges Like charges repel, unlike charges attract

3. Electrical Forces Electrical forces depend on 2 things: – The quantity of the charge involved – How far apart the charges are (the distance between the charges) closer farther apart

4. Friction Charging by rubbing together like walking across a carpet

5. Induction Neutral metal comb held near an object with a negative charge, comb becomes charged No touching!

6. Conduction Charging by touching

7. Types of Current Direct current Battery Alternating current School and home

8. Resistance Affected by – Thickness of a wire – Length of a wire – Temperature of a wire

9. Types of Circuits A circuit is a complete path for electricity to flow Series – Flow in one path – When an element in the path stops working, all elements stop Parallel – Flow is in more than one path – When one element stops working, the electricity can flow in other paths keeping the other elements working – Most circuits in home/school are parallel

10. Ground Fault Circuit Interrupters Shuts down a circuit when it senses unequal current going into and out of the circuit Often in kitchens and bathrooms because there is water that presents a shock hazard Other types of safety devices: fuses, circuit breakers

12. Semiconductors Crystalline solid Conducts electricity only under certain circumstances

13. Integrated Circuit Thin slice of silicon Solid state components Used in computers, cell phones, many electronics

14. Magnetic Force The force a magnet exerts on another magnet Iron or a similar metal On moving charges

15. Interaction Between Magnetic Poles Like poles repel each other Opposite poles attract each other Law of Electric Charges

16. Direction of Magnetic Poles Starting from the left what magnetic poles are shown on the two bar magnets? north, south, north, south

17. Magnetosphere Area surrounding Earth that is influenced by Earth’s magnetic field Helps protect the earth from the sun’s radiation Causes the aurora borealis/australis

18. Magnetic Domain A region that has a large number of atoms Magnetic fields are lined up parallel to a magnet’s field

19. Permanent Magnet A ferromagnetic material that has domains that remain aligned for a long period of time Neodymium (Nd) Iron (Fe), Cobalt (Co), Nickel (Ni)

20. Other Vocabulary Static discharge – Pathway through which charges can move suddenly – lightning Ohm’s Law – I = V/R – If you increase the resistance, the current decreases – I and R are indirectly proportional

21. Units Voltage = volt (v) Current = I (amps) Resistance = R (ohms, Ω) Power = P (watts) Energy = kilowatthours (kw h) Time = t (hours, h) Calculating your electrical bill: # of kw h x price/ kw h = what you owe 100 kw h x $0.185/ kwh = $18.50

22. Conductors and Insulators Conductor – Allows the flow of electricity easily – metals Insulator – Opposite of a conductor – Does not allow the flow of electricity easily – Glass, air, wood, rubber, plastic

23. Magnetic Field Moving electric charges Creates a magnetic field

24. Solenoid A coil of wire that is carrying a current Also produces a magnetic field

25. Electric Motor Periodically changing the direction of current in the electromagnet can cause the axle to spin because the magnetic field reverses direction

26. Generator A device that changes mechanical energy to electrical energy by rotating a coil of wire through a magnetic field

27. Fossil Fuels: Electricity Generation Heat from burning fuel creates steam that spins a turbine

28. Electromagnets Ferromagnetic core Solenoid Power source

29. Increasing the Strength of an Electromagnet More coils of the same length of wire A thicker core with the same length of wire Greater current with the same length of wire A combination of all of the above

30. Grounding Transfer of excess charge through a conductor to the Earth Lightning rod