Earth's Magnetic Field

Explaining how the Earth's Magnetic Field affects compasses.

What is Earths Magnetic Field?

Earths magnetic field is the magnetic field that stretches out from Earth’s outer core and meets the solar wind. Solar wind is a path of charged particles produce from the Sun. It’s size stretches from 25 to 65 microtesla.

How do you use a compass, and what is it.

A compass is a device that helps you navigate where you want to go. Its needle is attracted to Earths magnetic poles, the direction in which it is aiming is the North Pole. The left and right are East and West, and the opposite direction of North is South. A compass is very different from a GPS, a GPS tells you exactly where to go. On the other hand a compass only tells you where North, South, West, and East are you have to find the way to where you want to go.

How does Earths Magnetic Field affect compasses?

We have all seen compasses and we all know that they have a little dinky pointy needle in them, right? Well many might not know what that needle is used for, but that problem will be solved now. The earth's has North and South poles on each side of it that

Parts of a Compass

A compass is made up of 14 different parts...


  • The Baseline - it the flat bottom surface of the compass where everything else sits.
  • The Scales - The map scales on a compass.
  • The Direction-of-Travel Arrow - This is the arrow on the compass that you point to where you want to go. You point this to where you want to go.
  • Magnifier - Used to see small features on the compass.
  • Index Pointer - It is located at the edge of the dial and its where you take degree readings.
  • Dial - The dial is used for rotating the housing, it is a black ring located around the housing that has degree markings.
  • Declination Mark - used to position the compass in an area with known declination.
  • Orienting Arrow - This rotates with the housing when the dial is turned, you use it to orient a compass to a map.
  • Orienting Lines - Orienting Lines are a series of parallel lines marked on the base plate.
  • Needle - A magnetized needle that is attracted to the North Pole, one side of the needle is red to indicate the North Pole.
  • Housing - The housing is the main part of the compass, therefore the name, it is a round container that is filled with liquid. This part also holds the needle.
  • Bubble - This is a bubble in the liquid in the housing that helps you indicate if you are holding the compass level.
  • Mirror - The Mirror lets you see the compass face and distance objects.
  • Sight - Helps you aim your compass at distance objects.