Magnetism and Compasses

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

Why does a compass needle point north?

• The compass is a bar magnet

• Because north is up

• Because it's magic

• It lines up with the Earth's magnetic field

A ___________ is a device that has a magnetized needle that can spin freely. 

• magnet

• compass

• filing

• electron

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.

Which of these is a way to make an electromagnet stronger?​ ​ ​ ​ (a)  

• wrapping the wire around the iron core more

• putting a switch in the electrical circuit

• replacing the copper wire with plastic wire

• replacing the iron core with a copper core

Label the parts of the electromagnet.

a

b

c

d

nail

wire

power source

coil

Tags

NGSS.MS-PS2-3

How is Earth's magnetic field similar to that of a magnet?

• It is hundreds of miles long

• It has north and south poles

• It is made in Earth's core

• It is shaped like a horseshoe

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

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

• granite

• limestone

• iron

• nickel

A magnet that retains its magnetism after removal of the magnetizing force, used for compasses.

• Magnetic Poles

• Permanent Magnet

• Hard Magnet

• Soft Magnet