U 10Lesson 2 How Do Electric Charges Interact?

Jake hangs two balloons from a desk so that they are close together but not touching. Jake rubs one balloon with a wool cloth. He does nothing to the other balloon. What happens when he lets go of the balloons?

• They push one another apart.

• They are close together but do not touch.

• They touch one another and stick together.

• They touch one another and pop.

Min tapes a piece of string to each of two table tennis balls. He hangs the balls so that they are close to one another but do not touch. Later, he finds that they have pulled together. They are now touching. What could explain why the two balls are now touching?

• Both lost their charges.

• Both gained a negative charge.

• Both gained a positive charge.

• Both gained opposite charges.

Cecilia is combing her hair. What will most likely happen when she holds the comb near a small, uncharged object?

• The object will stay where it is.

• The object will gain a charge opposite that of the comb.

• The object will be pushed away by the comb.

• The object will stick to the comb.

Curtis uses a wool cloth to give a balloon a negative charge. What will happen if he holds the balloon near the wall, and why?

• The balloon will stick to the wall because a negatively charged object is attracted to an uncharged object.

• The balloon will not stick to the wall because a negatively charged object is repelled by another negatively charged object.

• The balloon will not stick to the wall because a negatively charged object is repelled by an uncharged object.

• The balloon will stick to the wall because a negatively charged object is attracted to another negatively charged object.

Carlos wanted to know how positive and negative charges affect balloons. The balloons shown below are part of his investigation.

How could Carlos cause the balloons to attract one another and stick together?

• Give them both a negative charge.

• Remove any positive or negative charge from both balloons.

• Give only one of them a positive or negative charge.

• Give them both a positive charge.

Aisha wanted to know how positive and negative charges affect balloons. The balloons shown below are part of her investigation.

• They are both positive.

• One is positive and one is negative.

• They are both uncharged.

• They are both negative.

The pictures below show objects that are charged and objects that are not charged. Which shows two objects with the same charge?

• 
• 
• 
• 

Wanda rubs a balloon against her wool sweater, and the balloon sticks to the sweater. Then she observes the balloon sticking to a wall. Why is this a scientific investigation but not an experiment?

• It uses balloons, which are not traditional objects of scientific study.

• Wanda observed something that can’t be explained by science.

• Wanda has not identified variables or created a controlled testing situation.

• . It involves an item of clothing, which cannot be observed with objectivity.

Which of the following best explains what happens when an object with a negative charge comes near another object with a negative charge?

• The objects will not move.

• The objects will cancel each other.

• The objects will attract each other.

• The objects will repel each other.