The Compass
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Basics on the topic The Compass
What is a Compass?
For a very long time, people have used a compass to determine the cardinal directions. The compass is a brilliant invention, commonly introduced to children in elementary school, where they learn how to use one. Before we examine the composition and functions of the compass in greater detail, here's a simple explanation of what a compass is:
A compass is a magnetized metal needle stuck onto a small pin and an indicator disk showing the cardinal directions. The magnetized needle of a compass always points northwards. If you align your compass with the northern direction indicated on the compass, you can determine all the cardinal directions.
The Composition of a Compass
Let’s look at how a compass is built:
Located within the compass is a so-called wind rose, usually displaying the four cardinal directions of north, east, south, and west, as well as the four ordinal directions of northeast, southeast, southwest, and northwest.
In the centre of the compass lies a small metal needle, which is magnetized and movable, typically coloured on the side that faces north.
The compass’s case is sometimes encircled by a rotatable bezel marked with numbers and degrees, which allows you to determine directions even more accurately.
How Does a Compass Work?
How do you use a compass? You hold the compass and rotate it until the coloured tip of the needle aligns with north. But why does the compass needle point north?
Deep within the earth are magnetic forces.
These magnetic forces are located roughly around the two poles of the earth, creating a magnetic north pole and a magnetic south pole, thus generating a magnetic field called the Earth's magnetic field.
Opposite poles attract—that's why the compass needle is magnetically charged in opposition with the Arctic magnetic pole in the north. This causes it to always rotate in the direction of north, towards its opposing pole.
The geographic pole and the magnetic pole in the Northern Hemisphere are not exactly located at the same point. The magnetic field also varies in different places, with the resulting discrepancies having little impact on compass accuracy in natural areas.
The compass can behave erratically if there is another magnet nearby. When the earth's magnetic field is distorted by another magnetic field, the compass needle can malfunction.
Navigation Using a Compass and a Map
Now that you know how to align the needle of the compass, you can use it to orient yourself in the field. When you align the compass needle along the north direction, you can read off all the cardinal directions on the compass.
You can also orient the map using the compass. Follow these steps to use a compass to orient the map:
| Step # | What to do |
|---|---|
| 1 | Place the compass onto the map so that the north direction on the compass points upwards. |
| 2 | Rotate the map until the compass needle aligns along the north direction. At this point, the map is now oriented, and you can read off in which direction things are located. |
Frequently Asked Questions about the Compass
The Compass exercise
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What are the parts of a compass?
HintsYou can use the compass to find locations on maps, but is the map a part of the compass?
The compass uses the Earth's magnetic poles, but does the compass have poles?
The compass needle is a small magnet that can move and spin freely to show the cardinal points. Though the compass needle spins, does the compass include a spinner?
SolutionThe parts of a compass are the:
- compass needle
- case
- cardinal points
- wind rose
The compass does not include a map, poles or a spinner.
- You can use the compass to find locations on maps, but the map is not part of the compass.
- The compass uses the Earth's magnetic poles, but it does not have poles.
- The compass needle is a small magnet that can move and spin freely to show the cardinal points. Though the compass needle spins, the compass doesn’t include a spinner.
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Can you label each of the cardinal points?
HintsWhat do the letters N, E, S, and W stand for?
Use the image to help you remember the four main cardinal points.
The wind rose helps us to see the points between the four main cardinal points. We can find northeast by looking between the cardinal directions north and east.
SolutionThe compass needle points to four cardinal points: north, south, east, and west.
The wind rose points to even more accurate cardinal points: northeast, southeast, southwest, and northwest. -
Help Mio understand how the compass works.
HintsRemember, the compass needle always points in the same direction. Which direction does it point in?
Remember, magnetism moves the compass needle.
Remember, magnets are attracted to the poles of the earth.
SolutionA compass works with an invisible force. We call it magnetism.
The earth acts like a giant magnet with two magnetic poles.
Magnets are attracted to the poles of the earth. The compass needle is a small magnet that can move freely.
One side of the compass needle is usually red and is always attracted to the north. -
How can Mio use his map to plan another route?
HintsUse the compass rose to help you.
We use the wind rose, underneath the compass needle, to read the different cardinal directions even more accurately.
Do you remember the cardinal directions on the wind rose?With a wind rose, you can read the different cardinal directions even more accurately.
SolutionMio will need to travel southeast.
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How can Mio plan a route with his compass and map?
HintsUse the compass rose to help you. Do you remember what the letters on the compass rose stand for?
On the compass, N stands for North, E stands for East, S stands for South and W stands for West.
Which way should Mio go to get to his friend's house?
In which direction is the arrow pointing?
SolutionMio will need to travel west to go to his friend's house.
Use the compass rose to help you work out which direction to go. On the map, we can see Mio's friends house is to the west of him. He will need to go west to reach his friend's house. -
Reading a map.
HintsHere are the images of each place in more detail to help you.
Use the compass rose on your map to help you.
The cardinal points on the compass tell you which way you need to go.
If Mio is traveling up, he is going north.
If Mio moves down, he is going south.
If Mio moves to the right, he is traveling east.
If Mio is traveling to the left, he is going west.Solution- Mio's house is southwest of Uma's house.
- The ice cream shop is west of the park.
- The park is northwest of the school.
- The school is east of Mio's house.
- Uma's house is northwest of the park.
- Mio's house is southwest of the park.
