You may have already heard that "opposites attract"; While it is not always the best advice for a relationship, it does represent the fundamental rule for the polarity of magnets. Since humans live on a huge magnet (planet Earth), by understanding how low-scale polarity works you can understand the mechanisms of the Earth's magnetic field that protects us from space radiation. Whether you want to distinguish the poles of a magnet to complete a fun science experiment or for future use, this article teaches you how to do it.
Steps
Method 1 of 3: with a Compass
Step 1. Gather the materials
You just need a compass and a magnet. You can use any type of compass, while finger or ring magnets are the simplest ones for this experiment.
Step 2. Test the compass
Although the tip of the needle that points north is usually colored red, this detail is worth checking out. If you know the direction of geographic north from your location, you can easily understand which point of the needle is pointing north.
- If you are not sure what the north direction is, you can still test the compass by going outside at noon, when the sun is higher in the sky; hold the compass on one hand so that the south cardinal point is close to your body.
- Observe the position of the needle. If you live in the northern hemisphere, the north end of the needle should point in your direction and south towards the sun, vice versa if you live in the southern hemisphere.
Step 3. Place the compass on a flat surface, such as a table
Make sure there are no other sources of magnetic fields or metals in the area that could alter the results; even a trivial object such as a keychain or pocket knife could cause interference. You can see that the north end of the compass needle points to true north.
Step 4. Place the magnet on the table
If you are using a circular magnet, the two poles are located on each of the flat faces; if you have opted for a bar, the poles are at the ends.
Step 5. Bring the magnet close to the compass
If you are using a circular model, you need to keep it straight, vertically so that one face is facing the compass.
If you are using a magnetic bar, place it perpendicular to the compass so that one end is close to the tool
Step 6. Look at the compass needle
Since it is actually a small magnet, its south end is attracted to the north end of your magnet.
If the north tip of the needle continues to face the magnet, you have found the south pole of the magnet. Rotate the magnet to expose the other end to the magnet, the south tip of the needle should be attracted to the north pole
Method 2 of 3: Create a Compass with the Magnetic Bar
Step 1. Find a segment of string
You can use any string or thread you have on hand, such as scrap yarn or ribbon; the string should be long enough to tie and hang the magnet.
Typically, one piece of yarn is enough, but you can estimate the length by holding it in your hands. Bring one end of the thread close to your nose using your right hand and extend your left arm as much as possible. The distance between the nose and the fingertips of the left hand should be almost one meter
Step 2. Tie the thread around the magnetic bar
Make sure the knot is tight so that the magnet cannot slip off; keep in mind that if you have a circular or spherical magnet, this method is not suitable.
Step 3. Keep the thread away from the body
Check that the bar is free to rotate and that it does not come into contact with any obstacles. When it stops, the end that is pointing north represents the north pole of the magnet. Congratulations, you have created a compass!
Notice the difference with the previous method, where the south end of the compass needle was attracted to the north pole of the magnet. When you use a magnet as if it were a compass, the north end points north because what is described as the "north pole of the magnet" should actually be more precisely defined as "pole pointing north", which is attracted to the south pole of the Earth's internal magnetic field
Method 3 of 3: Float the Magnet
Step 1. Gather the materials
This method involves using some commonly used items that you probably already have around the house. If you have a small magnet, a piece of Styrofoam, water and a cup, you can carry out this fun experiment to determine the polarity of the magnet.
Step 2. Fill a cup, bowl or saucer with water
There is no need to fill the container, it is enough that the polystyrene can float freely.
Step 3. Prepare the Styrofoam
It should be small enough to sit on the plate, but large enough to hold the magnet; if you have a large panel of this material, you can cut it to size.
Step 4. Place the magnet on the Styrofoam and put everything in the water
The floating platform should rotate until the north pole of the magnet faces true north.
Advice
- If you have to regularly check the polarity of the magnets, you can buy a specific device that allows you to do this without too much effort.
- You can use any magnet that you have already assigned the south and north poles to detect the polarity of other magnets. The south end of one magnet will spontaneously attach to the north end of the other.
