MINDS ON Think of a time you got a shock from something. Did it hurt? Why? Think of a time you got a shock from something. Did it hurt? Why? What do you think happened? What do you think happened? How do you prevent it? How do you prevent it? Is there a time or place when you tend to get more or less shocks? Is there a time or place when you tend to get more or less shocks?

CHARGING BY CONTACT Write Yellow Text Only

LEARNING GOALS I will be able to use the electrostatic series to identify charges when charging objects by friction. I will be able to use the electrostatic series to identify charges when charging objects by friction. I will be able to determine the change in charge when objects are charged by contact. I will be able to determine the change in charge when objects are charged by contact.

1. CHARGING BY FRICTION Occurs when two neutral materials are rubbed together. Occurs when two neutral materials are rubbed together. When this happens When this happens One material will attract extra electrons (become negative) One material will attract extra electrons (become negative) One material will give up extra electrons (become positive) One material will give up extra electrons (become positive)

THE ELECTROSTATIC SERIES  list of materials arranged in order of their tendency to gain electrons. How does it work?  material lower on list will take electrons from material higher on list Material Human Skin Rabbit Fur Acetate Glass Human Hair Nylon Wool Cat Fur Silk Paper Cotton Wood Amber Rubber Balloon Vinyl Polyester Ebonite Plastic (Likely to surrender electrons) + (Likely to gain electrons) -

THE BALLOON DEMONSTRATION Consider a rubber balloon being rubbed on a cotton sweater. Consider a rubber balloon being rubbed on a cotton sweater. 1.To which material were electrons transferred? Why? 2.What is the overall charge of both materials after the contact? 3.Why does the balloon stick to the sweater?

TRY THIS Activity p473 of text book! Activity p473 of text book! Work with elbow partner. Work with elbow partner. Follow procedures 1-5 and answer questions A, B, C. Follow procedures 1-5 and answer questions A, B, C.

2. CHARGING BY CONDUCTION Transferring of charges by direct contact: Transferring of charges by direct contact: End result: charges are equal. End result: charges are equal.

3. GROUNDING The removal of excess electric charge on an object by connecting it to the earth. The removal of excess electric charge on an object by connecting it to the earth. You have experienced this when: You have experienced this when: Shocked by a car door Shocked by a car door Shocked by a door handle after walking on carpet Shocked by a door handle after walking on carpet You have seen a lightning storm You have seen a lightning storm After grounding, the object returns to a neutral charge. After grounding, the object returns to a neutral charge. Symbol for grounding

APPLICATIONS 1.Electrostatic dusters (swiffers) Uses static electricity to attract dust from floors Uses static electricity to attract dust from floors 2.Electrostatic precipitators Uses static electricity to attract ash and dust particles from smoke stacks Uses static electricity to attract ash and dust particles from smoke stacks Can reduce harmful particle emissions by 99% Can reduce harmful particle emissions by 99%

LEARNING GOALS REVISITED I will be able to use the electrostatic series to identify charges when charging objects by friction. I will be able to use the electrostatic series to identify charges when charging objects by friction. I will be able to determine the change in charge when objects are charged by contact. I will be able to determine the change in charge when objects are charged by contact.

YOUR TURN P477 #1-3, 5,6,8. P477 #1-3, 5,6,8.