1. Chapter 1

2. Before the strips of newspaper were in contact with the plastic bag: they hung straight down while touching each other After sliding the plastic bag over them: they REPELLED each other WHY? Rubbing the plastic bag charges the strips with like charges. Like charges REPEL (try to get as far away from each other as possible)

3. Smallest unit of material that still has the characteristics of that material What makes up an atom? Protons: positive Neutrons: neutral Electrons: negative What is the overall charge on an atom? NEUTRAL (ZERO)

4. Particles with unlike charges attract - pull on each other Particles with like charges repel – push each other away Can be 2 positive or 2 negative charges Attraction Repulsion

5. A buildup of electric charge in an object caused by the presence of many particles with the same charge Materials can have: Positive charge: more protons than electrons Negative charge: more electrons than protons Electrons move more easily than protons – charges result from their movement 2 Types of static charge: Charging by contact Charging by induction

6. At first, a glass rod and balloon each have balanced, neutral charge When they touch, electrons move from the rod to the balloon Afterwards, the balloon has a negative charge and the rod has a positive charge

7. How does it work? Builds up STRONG electric charge through contact As the sphere takes on negative charge  electrons spread over the students skin and hair Hairs now all have same charge and repel one another

8. Charging By Contact SKIN GLASS HAIR NYLON WOOL FUR SILK PAPER RUBBER POLYESTER Materials higher on the list tend to give up electrons to materials lower on the list

9. At first, the rod has a negative charge and the balloon has a balanced charge When the rod come close to the balloon, electrons in the balloon move away from the rod When the rod is removed, electrons in the balloon spread out evenly as before

10. Draw a diagram of what is occurring between the newspaper strips and the plastic bag.

11. What is occurring in this situation? Before the charged balloon comes near the wall, the atoms in the surface of the wall are neutral As the balloon nears the wall, the electrons move deeper into the wall leaving the wall closest to the balloon with a positive charge

12. Section 1.2

13. The force of attraction or repulsion between charged particles.

14. Energy a charged particle has due to its position in an electric field Like charges repel: EPE increases when particles with like charges are pushed closer together Opposite charges attract: EPE decreases when particles with like charges move away from one another EPE is measured in volts

15. What happened in the bulb when the spark jumped? The bulb lit up briefly How might you explain this observation? A static charge moved from the balloon to the bulb and lit the bulb

16. Charge Separation: Collisions between particles in storm clouds separate charges. Negatively charged particles collect at the bottom of the cloud Charge Buildup: The negatively charged bottom of the cloud induces a positive charge in the surface of the ground. Static Discharge: The charge jumps through the air to the ground. The energy released by the discharge causes thunder and lightning.

17. Conductors Material that allows electric charge to pass through easily Examples: iron, steel, copper, aluminum Insulators Material that does not allow electric charge to pass through it Important in electrical safety because they keep charge away from the body Examples: plastic, rubber

18. Materials resist the movement of a charge in different amounts Electrical resistance: the property of a material that determines how easily a charge can move through it Units: ohms (Ω) Factors that affect resistance: Type of material – conductors have LOW resistance; insulators have HIGH resistance Amount – a long wire has more resistance than a short wire Shape – a thin wire has more resistance than a thick wire

19. Providing a harmless, low resistance path (a ground) for electricity to follow. In many cases  this path actually leads to the ground EXAMPLE: Protect buildings from damage by lightning : Most building have a lightning rod located high up on the building, which is made of a material that is a good conductor The rod is connected to a conductor cable, which is connected into the ground. Lightning hits the rod and passes harmlessly through the cable into the ground

21. SECTION 1.3

22. Static charge cannot make your TV or other electronics play. Static charge contains a limited amount of charge Static charges moves from higher to lower potential Electric current: flow of charge Some electrical pathways receive a continuous supply of charge (the difference between the 2 ends of the pathway are the same)

23. Can only flow if it has a pathway to follow – a material to conduct it Charge flows from higher to lower potential Charge that flows steadily has a certain rate of flow. Standard unit of measure: ampere (amp) Amount of charge that flows past a given point per unit of time Low PressureHigh Pressure Low rate of flowHigh rate of flow

24. Recall: measured in ohms (Ω) Current decreases as resistance increases Low ResistanceHigh Resistance High rate of flowLow rate of flow

25. Current = ____Voltage______ I = __V__ Resistance R

26. What is the current in an electrical pathway with an electrical potential of 120 volts and a resistance of 60 Ω?

27. V = 120 V R = 60 Ω I = ?

28. I = _V_ R

29. I = 120 V 60Ω I = 2 A

30. What is the voltage of a circuit with 15 amps of current and toaster with 8 ohms of resistance?

31. Produces electric current using the chemical or physical properties of different materials Example: batteries 2 Types: Primary cells Storage cells

32. Produce electric current through chemical reactions Reactions continue until the chemicals are used up Example: dry cell battery

33. Produce current through chemical reactions that can be reversed inside the battery Example: Car Battery Discharging: when storage cells are producing current Battery discharges to operate the motor Operate lights when car is off Charging: sending current through the battery in the opposite direction (reverses reaction) When car is running, battery is continually being charged Car’s alternator produces the current. Current from alternator runs through battery in reverse to recharge