1 min
Image: Garry Gay/Getty Images

Before GPS satellites and other high-tech navigational aids came on the market, people oriented themselves using compasses. A compass will point toward the North Pole and help you find your way. Which way will you be facing when you finish this quiz?
The magnet used in a magnetic compass is usually called:
the needle
the pointer
the bar

A compass' small, lightweight magnet, or needle, is balanced on a nearly frictionless pivot point.

How do you know when the needle is pointing north?
The compass heats up.
The needle starts vibrating.
One end of the needle is colored to indicate it's pointing north.

One end of the needle is often marked "N," for north, or colored in some way to indicate that it points toward north.

Why does a compass have a lightweight magnet and a frictionless bearing?
to make it easier to carry
to make the compass more affordable
to allow the needle to turn easier

The Earth's diameter is about 8,000 miles (12,875 kilometers), which is a long way for the planet's magnetic field to go before affecting your compass. That's why a compass has a lightweight magnet and a frictionless bearing -- otherwise, there just isn't enough strength in the Earth's magnetic field to turn the needle.

According to a theory, what causes the Earth's magnetic forces?
the interaction of gravity with the sun and the moon
the rotational forces within the Earth's liquid iron layer
the interaction of complicated wind patterns and ocean currents

Convection caused by heat radiating from the Earth's core, along with the rotation of the Earth, may be what causes the liquid iron of the Earth's core to rotate and create a magnetic field.

What's one way to change a needle (or other wirelike piece of steel) into a magnet?
rub it against another needle
stroke it with a magnet
heat it and then quickly freeze it

You can magnetize a needle by stroking it with a magnet 10 to 20 times.

Ships and airplanes use what type of compass?
magnetic compass
gyroscopic compass
pressurized compass

Because of the trouble encountered by magnetic compasses on moving platforms, many ships and planes instead use gyroscopic compasses.

What's one of the problems encountered by magnetic compasses on moving platforms?
the compasses correct themselves too slowly
the needles lose their magnetic force
the friction is too great

Not only do magnetic compasses correct themselves slowly when the platform turns, but they also must be kept level to work properly.

What keeps a gyrocompass pointing in the same direction even when moved or rotated?
a gyroscope
gravitational forces
water

A spinning gyroscope inside the compass, fueled by a small motor, keeps the needle pointing north even in rough seas or turbulence.

How is the needle of a gyrocompass initially oriented north?
with a gyroscope
with a magnetic compass
with a motor

The axis of a gyrocompass is pointed north using a magnetic compass as a reference. Magnetic compasses are also periodically used to correct any errors picked up by the gyrocompass.

Which of the following do you not need in order to make your own compass?
a shallow dish of water
something small that floats
thick string