Magnetic Field and Magnetic Lines of Force

What is our best evidence that Earth has a magnetic field?

• All things fall toward Earth's center

• A compass needle lines up with it

• Winds blow from east to west

• Earth's oceans all have currents

Earth's magnetic field and a bar magnet attract particles to the same locations. Where are they?

• The middle

• All around the outside

• The north and south poles

• First to the middle, then to the ends

The region in which Earth's magnetic field is found is called the:

• atmosphere

• stratosphere

• aurora

• magnetosphere

Which way will the magnets move after they are released?

• Towards each other

• Away from each other

• Not enough information

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Which of the following statements is true about Earth’s magnetic poles?

• They are the areas where Earth’s magnetic field is strongest.

• They are located at Earth’s geographic poles.

• They are the areas where Earth’s magnetic field is weakest.

• Earth has four magnetic poles.

Earth acts like a giant magnet because its center is made up MOSTLY of:

• granite

• limestone

• iron

• nickel

What causes the magnetic field to form in an electromagnet?

• Electromagnets are only called magnets because electricity is involved.

• The domains of the magnet become aligned

• The magnetic field is absorbed from another magnet

• Electric current flowing in a wire

Tags

NGSS.MS-PS2-3

You can cause a permanent magnet to lose its magnetic field if

• You forcefully vibrate the object, causing its domains to fall out of alignment.

• By rubbing an iron object with a permanent magnet in the same direction repeatedly.

• You freeze the object.

• You connect the north and south poles of two magnets.

Tags

NGSS.MS-PS2-5

Magnetic fields are strongest

• between the poles

• at the north pole

• at the south pole

• at both poles

An electromagnet can be strengthened if

• less coils are added to the iron core

• the iron core is removed

• more current runs through the wire

• a nickel or cobalt iron core is used.