Unit 7 Matter and Electricity

How would a crane operator using an electromagnet drop metal into the shipping container?

• Turn on a magnetic charge in the container

• Turn off the electric current in the electromagnet

• Send out a signal causing the container to become an electromagnet

• Send out an a signal to block the properties of scrap metal

Choose magnetic materials.

• Plastic and copper

• Steel and iron

• Cardboard and wood

• Cloth and paper

Steel cans are separated from aluminum cans in a recycling center. Which of the following is the best way the recycling center can separate the steel cans from the aluminum cans?

• sort the cans by size

• put the cans in water

• cool the cans to a low temperature

• put the cans under an electromagnet

A student builds a compass from a pencil, a clear plastic cup, some thread, and a magnetized needle. The student then brings the north end of a bar magnet near the north end of the needle, as shown below.

What happens when the north end of the bar magnet is brought near the north end of the compass needle?

• The north end of the needle spins away from the bar magnet.

• The north end of the needle sticks to the bar magnet.

• The needle and cup slide across the table.

• The needle and cup stay in place.

Which is an example of a temporary magnet?

• a horseshoe magnet

• a bar magnet

• magnetite

• an electromagnet

Two bar magnets are placed end to end. The north pole of one magnet is next to the north pole of the second magnet. How will the magnets respond?

• They will attract one another.

• The first magnet will jump up.

• They will repel one another.

• Nothing will happen

Why do electrical plugs have a plastic body?

• Plastic is an insulator.

• Plastic is a conductor.

• Plastic doesn't melt very well.

• Plastic is hard.

Name the parts needed to create a simple circuit.

• wires, a flip, work (bulb)

• a power source and a switch

• wires, a power source, work (bulb)

• a power source, clips, magnet

In which circuit are both bulbs lit?

• A

• B

• C

• D

What slows the flow of heat and electricity?

• insulator

• resistance

• circuit

• conductor