How to determine the polarity of a magnet

Content

Steps
Method 1 of 3: Use a compass
Method 2 of 3: Make a compass from a bar magnet
Method 3 of 3: Place the magnet on the water
Tips
Warnings
What do you need

You've probably heard the phrase "opposite poles attract." Although this is not always true for relationships between people, this rule is invariably true for magnets. We are all used to dealing with a large magnet - the Earth. Experiments with small magnets will help you understand how the Earth's magnetic field works, which protects us from cosmic radiation. Whether you want to mark the poles of a magnet for convenience or conduct an interesting physics experiment, the ability to determine the polarity of magnets comes in handy.

Steps

Method 1 of 3: Use a compass

1 Collect everything you need. All you need is a compass and a magnet. Any compass will work for this method, but a simple disc or bar magnet is best used as the magnet.
2 Check the compass. Although the north-pointing end of the compass needle is usually colored red, it does not hurt to check the compass again. If you know where north is in your area, you can easily determine which end of the compass needle points in that direction.
- If you don't know where north is, you can go outside with a compass at noon when the sun is at the highest point in the sky (zenith). Take the compass in your hand so that it is horizontal and face the sun.
- Look at the location of the compass needle. If you live in the Northern Hemisphere, the north end of the arrow points towards you, and the south end of the arrow points to the sun. If you live in the Southern Hemisphere, the arrow will turn towards you with its southern end.
3 Place the compass on a flat, horizontal surface such as a table. The surface must not be magnetized or metallic, as this can distort the result. Even little things like a key chain or pocket knife can affect the result of an experiment. The north end of the compass needle should point north.
4 Place the magnet on the table. If you are using a disc magnet, the north and south poles will be on opposite flat faces. The poles of the bar magnet are located at its ends.
5 Bring the magnet to the compass. If you have a disc magnet, place it on its side and turn it with your index finger so that one flat edge is facing the compass.
- If you have a bar magnet, place it on a table with one end of the magnet pointing towards the compass.
6 Look at the compass needle. Since the compass needle is a small magnet, its south end will be attracted to the north pole of the magnet.
- If the compass needle has turned towards the magnet with its north end, the south pole of the magnet is near the compass. Turn the magnet so that its second (north) pole is facing the compass: now the compass needle will turn towards the magnet with its southern end.

Method 2 of 3: Make a compass from a bar magnet

1 Find a thread that is long enough. You can use any thread or string that can support the weight of the magnet. They should be long enough to strap and hang the magnet.
- As a rule, a meter thread is sufficient. The length of the thread can be estimated as follows. Take the thread with both hands. Bring your right hand with the thread to your nose, and extend your left as far as possible. In this case, between the right and left hands, you get about one meter.
2 Tie the string around the magnet securely. Tighten the thread firmly to prevent the magnet from slipping out. Please note that this method is not suitable for a disc or spherical magnet.
3 Lift the magnet by the thread so that it hangs freely in the air. Make sure that nothing interferes with the magnet: it should rotate freely around its axis. When the magnet stops spinning, its north pole will point north. So you've made a compass!
- Note the difference from the previous method, in which the south end of the compass needle was attracted to the north pole of the magnet. When we use a magnet as a compass, its north pole will be facing north, which is correctly called the positive magnetic pole, or the pole pointing north, since in the physical sense, the earth's north magnetic pole is south, since it attracts the north pole of the magnet.

Method 3 of 3: Place the magnet on the water

1 Collect everything you need. For this method, you will need several items that you probably have in your home. If you have a small magnet, a piece of Styrofoam, water, and a cup on hand, you can do a fun experiment to determine the polarity of a magnet.
2 Pour water into a cup, bowl, or deep dish. There is no need to pour water to the brim, just enough for a piece of foam to float freely in it.
3 Prepare the styrofoam. Choose a piece of Styrofoam that can float freely in a container of water while still holding your magnet around it. If you have a large sheet of styrofoam, cut off the desired piece.
4 Place the magnet on the styrofoam and submerge it in the water. This will rotate the foam so that the north pole of the magnet points north.

Tips

If you need to regularly check the polarity of the magnets, a magnetic pole detector can be purchased for convenience and to save time.
Any magnet with a known polarity can be used to determine the polarity of another magnet. In this case, the south pole of one magnet will be attracted to the north pole of the second magnet.

Warnings

A magnet can reverse the polarity of the compass. Remove all magnets and metal objects from the compass and check to see if the north end of its arrow is still pointing north.