1. Hello Scientists! Today: Correct Electrostatics Review Assignment: Waves Review Homework: Study for the Electrostatics and Waves Assessment

2. Electrostatics Review 1.Name the three parts of the atom and their charge. a) Protons (+1) b) Electrons (- 1) c) Neutrons (neutral) 2.Objects tend to have a neutral charge because they have the same number of electrons and protons. 3.An object that gains electrons will have a negative charge while an object which loses electrons will have a positive charge.

3. Electrostatics Review 4.What are the three principles of static electricity you learned? a)Opposite charges attract b) Like charges repel c) Only electrons move when charge is transferred. 5.Some examples of objects that tend to give up electrons are: Glass Human hair wool 6.Some examples of objects that tend to take in electrons are: Rubber Plastic Styrofoam

4. Electrostatics Review 7.When combing your hair, you scuff electrons from your hair onto the comb. What is the charge on your hair? Positive How about the comb? Negative 8.Which would be safer, a house with no lightning rod or a house with a lightning rod not connected to the ground? Explain. A house with no lightening rod because it will be less “attractive to a lightning bolt. A lightning rod not connected to the ground would transfer the electric discharge to the house and cause a fire. 9.What safety is offered by staying inside an automobile during a thunderstorm? The rubber in the tires keeps you from being connected to the ground as the electricity flows over your car.

5. Electrostatics Review 10.Charging an object by touching is called charging by conduction while charging an object by bringing another charged object close to it, and without touching, is called charging by induction. 11.When an insulator (think about the Styrofoam pad we used) is charged, the charges will build up on the object, while the charges will flow through a conductor. 12.When charging by induction occurs, the overall object remains neutral but the charges within the object become separated. 13.What does grounding mean in the area of electrostatics? Grounding means an object is connected to the ground or another object so that any excess electric charge can flow to the ground. That way, the electricity won’t go through you if you touch the charged object.

6. Electrostatic Review 14. The balloon at right has been rubbed on Sue D. Nym’s head and then hung from the ceiling. A negatively charged rod is brought close to the balloon and the rod repels the balloon. a)What charge does the balloon have? Negative What is this method of charging called? Rubbing a)How do you know this? Because the balloon is repelled by the negatively charged object so it must have the same charge. a)What was the type of charge on Sue’s hair immediately after the balloon was rubbed on it? Positive a)Explain how her hair gained this charge Her hair became positively charged because the rubbing caused electrons to be transferred to the rod. ?

7. Electrostatics Review 15.Your physics teacher has prepared the room for the class's entry by suspending several inflated balloons from the ceiling. Upon entering the physics room, you observe two balloons being drawn towards each other as shown at the right. The attraction of these balloons for one another provides evidence that ______. a. both balloons are charged with the same type of charge b. both balloons are charged with the opposite type of charge c. both balloons are charged - either with the same type or opposite type of charge d. only one of the balloons is charged; the other is neutral e. at least one of the balloons is charged; the other is either charged or neutral

8. Electrostatics Review 16.As you look around the room, you observe two other balloons being pushed away from each other as shown at the right. The repulsion of these balloons from one another provides evidence that ______. a. both balloons are charged with the same type of charge b. both balloons are charged with the opposite type of charge c. both balloons are charged - either with the same type or opposite type of charge d. only one of the balloons is charged; the other is neutral e. at least one of the balloons is charged; the other is either charged or neutral

9. Electrostatics Review 17.In one part of the room, there are two balloons - one hanging straight down and the other being attracted to it. This is evidence that _____. a. balloon A is charged and balloon B is neutral b. balloon B is charged and balloon A is neutral c. balloon A is neutral and balloon B is negative d. balloon A is neutral and balloon B is positive e. … nonsense! This would never happen if the balloons are identical and simply suspended by strings. They will attract each other and both be deflected from a vertical orientation

10. Electrostatics Review Positive or neutral Negative Positive Positive or neutral Negative