8.PS2.1 Electromagnetism

A student designed and constructed a rotational/rotary electrical generator in his physics class to investigate cause and effect connections about magnetism and electricity. When he first tested this generator, it only produced 50 amps. However, his goal was for this generator to induce 100 amps.

What is one action that he could do to make this happen?

• Use an electromagnet

• Add an iron core

• Rotate the coil more quickly

Tags

NGSS.MS-ETS1-3

NGSS.MS-PS3-5

A science teacher asked his students to do hands-on experiments in class to investigate ways to increase the lifting capacity of electromagnets. A team of students constructed two models (see diagrams).

Two-Part Question

1) Which one of these models will have a more powerful magnetic field?

2) Which cause and effect explanation best validates your first answer.

• Model Two will have a stronger magnetic field

  Cause: More electricity (12V battery vs 1.5V) and more coils (10 wraps vs 4)

  Effect: Greater magnetic field strength

• Model Two will have a stronger magnetic field

  Cause: This model will have a faster rotation which will produce more electricity.

  Effect: More electricity will result in a stronger magnetic field.

• Model One will have a stronger magnetic field

  Cause: This model has four coils which will produce more electricity.

  Effect: More electricity will result in a stronger magnetic field.

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

A student built a prototype of a simple electromagnet using a nail, some length of wire, and a battery with the goal of using it to lift three paperclips.When the student first tested this prototype, it could only lift one paperclip.

What design change would increase the magnetic field strength of this electromagnet so that it would lift three paper clips?

• Remove the nail from within the coil.

• Move the battery closer to the nail.

• Increase the number of loops in the coil.

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

A team of four students were asked to create a model of an electrical generator. Each team member created one model displaying electromagnetic phenomenon (see pictures below).

Select the model shown below that is demonstrating electricity being induced.

• A

• B

• C

Tags

NGSS.HS-PS2-5

Examine the two models of electromagnets shown. A group of students constructed a model of an electromagnet which was able to lift two paper clips (see Model W above).

1) How does electricity moving through the wire convert the nail into a temporary magnet?
2) Model W can only lift two paper clips. What change would enable it to lift more paper clips?

• 1) A non-contact force (nuclear strong force) forms a magnetic field in the nail.
  2) To solve this problem, they could use a plastic or glass core (see Model X).

• 1) Electrical current forms a magnetic field which realigns the atoms in the nail.
  2) One solution is to add more coils to the iron core (see Model X above).

• 1) A non-contact force (gravitational attraction) realigns the atoms in the nail.

  2) One solution to this problem is to add more batteries to the model.
  

Tags

NGSS.MS-PS2-3

Examine the apparatus shown in the illustration containing two circular magnets. Notice that magnet A is levitating above magnet B due to a non-contact force.

Which of the following statements correctly describes what is happening in this diagram?

• The polarity of the top of magnet B is the opposite polarity of the bottom of magnet A. This is showing wave refraction (waves bending).

• The bottom of magnet A is a north pole, and the bottom of magnet B is also a north pole. This is showing magnetic attraction (opposites attract).

• The polarity at the top of magnet B is the same as the polarity at the bottom of magnet A. This is showing magnetic repulsion (like repels).

Tags

NGSS.MS-PS2-5

Using 50 centimetres of copper wire, a bar magnet, and an amperage gauge, construct a device that will induce electrical current (build an electrical generator).

Which one of these models successfully accomplished the design task, and what is wrong about the other three models?

• Model Beta is an electromagnet. All other models merely show magnetic fields.

• Model Beta is an electrical generator. The other models merely show magnets.

• Model Delta is inducing electricity. The other models merely show magnetic fields.

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

Two students decided to use their knowledge about non-contact forces to build a hoverboard park. They embedded thousands of bar magnets into the surface of the floor with the north poles facing up.

• ---Instead of magnets, they could simply mount wheels on the board.

  ---This would demonstrate electrostatic force.

• ---The bottom of the hoverboard would have to be a north pole.

  ---This would demonstrate magnetism.

• ---The bottom of the hoverboard would have to be a south pole.

  ---This would demonstrate gravity.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

MRI machines use magnetic fields from powerful electromagnets to create images of the inside of a person’s body. How are the electromagnets in a MRI machine similar to all other electromagnets, and how could a doctor increase a MRI machines’ magnetic field (Select two choices).

• They have coils of wire wrapped around iron cores connected to electrical current.

• MRI machines consist of many permanent magnets that cannot be turned off.

• To increase the magnetic field of an MRI machine, increase the electrical current.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

Non-contact forces can be either attractive or repulsive. A student was asked to demonstrate that fields exist between objects exerting forces on each other even though the objects are not in contact. The results of this demonstration are shown.

Select two pictures that show repulsion, and determine which kind of non-contact force these pictures are displaying. (Select two choices).

• Picture 04 shows electrostatic repulsion.

• Picture 01 is demonstrating magnetic attraction.

• Picture 03 is demonstrating magnetic repulsion.

• Picture 04 is demonstrating magnetic repulsion.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5