Forces that Act from a Distance

Which magnets will attract each other? Circle the letter of the correct answer.

• A

• B

• C

• D

Mary made a metal game board and put it on her wall. She made wooden game pieces to put on the game board. She wants the game pieces to stay on the board without falling off. The game pieces should be easy to remove so she can play the game again. How should she attach the game pieces to the board? Circle the letter of the correct answer.

• glue

• nails

• buttons

• magnets

Hector rubs a comb with a wool cloth. Next, he holds the comb near, but not touching, some bits of paper on a plate. Which of these is most likely to happen?

• . The paper bits will move away from the comb.

• The paper bits will not be attracted to the comb.

• A spark will jump between the paper bits and the comb

• The paper bits will be attracted to the comb and will stick to it.

Hector wants to build an electromagnet so the crane of his train set to lift, move, and release cars from one track to another. His supply list includes a 3" steel nail, insulated wires, a battery holder, batteries, and a switch. He builds and tests the electromagnet but it is not strong enough to lift a train car.

Pick two choices that would increase the strength of the electromagnet.

• Add another switch to the electromagnet.

• Increase the length of the wires attached to the battery.

• . Increase the number of batteries used in the electromagnet.

• Increase the number of times the wire is wound around the nail.

At an assembly about electricity, Marcie and Eric were picked as volunteers to test the Van de Graaff machine on stage. This machine makes static electricity. When Eric touched the machine, his short hair lifted and separated all over his head. When it was Marcie’s turn, some of her long hair lifted and separated a little.

Complete the passage.

Eric’s hair lifted and separated because his hair was ____________ and ____________.

• Short and light

• long and heavy

• the static electricity’s force was stronger than gravity lifting and separating the hair.

• gravity was stronger than the static electricity’s force pulling the hair down.

At an assembly about electricity, Marcie and Eric were picked as volunteers to test the Van de Graaff machine on stage. This machine makes static electricity. When Eric touched the machine, his short hair lifted and separated all over his head. When it was Marcie’s turn, some of her long hair lifted and separated a little.

Complete the passage.

Only some of Marcie’s hair lifted and separated because her hair was ____________ and ____________.

• long and heavy

• short and light

• gravity was stronger than the static electricity’s force pulling the hair down

• the static electricity’s force was stronger than gravity lifting the hair up

Identify the pair of magnets that will repel each other, A or B.

• A

• B

What would make this set of magnets attract?

• keep them the same

• turn one of the magnet so you have two opposite poles

• turn both magnets so you have to similar poles again.