Magnets and Electromagnets NOT FINISHED

Maglev trains, like the one shown in the picture, use magnet fields to travel up to 600 miles per hour. Magnets on the bottom of the train and on the tops of the rails have similar magnetic poles. Based on properties of magnets, how do these magnets affect the train?

• The two magnetic fields repel each other, causing the train to levitate, or hover, above the rails.

• The powerful magnets greatly reduce the force of gravity, resulting in less friction and greater speed.

• The train is able to stop immediately because the magnets on the rails attract the magnets on the train.

• Maglev trains have extremely powerful magnets, greatly decreasing the force of gravity and allowing them to float.

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NGSS.MS-PS2-1

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Four students are investigating electric motors. They have created an electric motor as shown in the diagram below.

Which of the following changes should the students make if the students want to decrease the strength of the motor?

• Increase the voltage of the power source being used to operate the motor.

• Reduce the number of coils of copper wire.

• Change the configuration of the magnets in relation to the copper wire.

• Add a reducer cap to the end of the axle to inhibit movement.

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NGSS.HS-PS3-3

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Magnetic fields are areas where an object exhibits a magnetic influence. The fields affect neighboring objects along things called magnetic field lines. A magnetic object can attract or push away another magnetic object.

Can you identify the images that represent magnetic fields?

Check each image that is correct.

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Scientists and engineers around the world use the force of magnets to solve a variety of problems. For example, maglev trains use magnetic fields to move people quickly and safely, helping to clear road traffic and save people travel time. The magnets shown in the image are interacting much like the magnets of a maglev train. The magnets on the bottom of the train interact with the magnets on the rails below it, allowing the train to hover over (not touching) the tracks.

If the top of the first magnet is its south pole, what are the tops of the second magnet (Side A), and the third magnet (Side C)?

• Side A: north pole, Side C: south pole

• Side A: north pole, Side C: north pole

• Side A: south pole, Side C: south pole

• Side A: south pole, Side C: north pole

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NGSS.MS-PS2-3

NGSS.MS-PS2-5

A student is investigating magnetic fields with two magnets as shown below. The student wants to see where a magnetic field is the strongest.

Which of the following procedures would help the student find the location where the magnetic field is the strongest?

• 1. Obtain two horseshoe magnets

  2. Arrange the magnets so that the two bar magnets are touching in the middle, and the two horseshoe magnets are on the outside

  3. Try pulling all of the magnets apart and pushing them back together

  4. Repeat step 3 five times

  5. Record your observations

• 1. Place magnets on a sheet of white paper

  2. Sprinkle iron filings on the sheet of paper

  3. Position the magnets so that they are attracted to an opposite end

  4. Make sure the magnets are 3 cm apart

  5. Observe the locations with the most iron filings

  6. Record your observations

• 1. Turn one magnet so that the two bar magnets repel each other

  2. Using your hands forcefully try to push the two magnets together

  3. Obtain a paperclip, wooden pencil, and large pink eraser

  4. Try pushing the same repelling ends together with the paperclip located in between the two magnets

  5. Repeat set 4 with the pencil and eraser

  6. Record your observations

• 1. Place magnets into a plastic try with at least 1 inch of water

  2. Manipulate the magnets to attract and repel each other

  3. Remove magnets from the tray

  4. Add 2 mL dish soap to the tray of water and gently stir to avoid foaming

  5. Replace magnets and repeat set 2

  6. Record your observations

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NGSS.MS-PS2-3

NGSS.MS-PS2-5

Renaldo and Nasreen build an electromagnet by wrapping a wire around a nail and connecting the wire to both terminals of a battery. When they test the electromagnet, it can pick up 6 paper clips. Their teacher wants all groups to pick up at least 10 paper clips.

What could Renaldo and Nasreen do to increase the number of paper clips their electromagnet picks up?

• make the wire longer

• remove the nail from the center of the wire

• increase the number of loops of wire around the nail

• spread the loops of wire apart on the nail so they do not touch

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NGSS.MS-ETS1-1

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Bradley connected the loose wire to the battery and created an electromagnet. He picked up 45 thumb tacks with his electromagnet, though his goal was to pick up 50 thumb tacks. What could Bradley do to increase the strength of his electromagnet and pick up more thumbtacks?

• Use fewer coils of wire.

• Use a screw instead of a nail.

• Use two batteries instead of one.

• Replace the nail with a piece of steel.

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NGSS.MS-ETS1-1

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When magnets come within the magnetic fields of other magnets, they move toward or away from each other, depending on their poles. The door latch shown in the picture is one of many ways magnets can be used in everyday life.

How are magnets most likely used in this latch?

• Magnets with opposite poles are attached to the door and floor, when they come in contact, they attract one another and latch the door.

• The magnets are extremely heavy, so when the door is open, the latch on the floor pulls on the magnet, making the door too heavy to close.

• The door magnets are turned on and off by the switch on the floor. When the door is over the latch, the magnets turn on, latching the door in place.

• Magnets with similar poles are placed on the floor latch and on the door, which attract one another when they are close, latching the door in place.

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Which of these are characteristics of both magnets and electromagnets?

(Choose 2)

• attracts iron

• core is nickel, cobalt or iron

• requires electricity to work

• Normally made of several parts; wire battery, nail

• Always works

Which of these are characteristics of only electromagnets?

(Choose 2)

• attracts iron

• Usually one solid piece

• requires electricity to work

• Normally made of several parts; wire battery, nail

• Always works