People have been aware of magnets for thousands of years. We rely on them every day in many of the different objects we utilize all the time. A magnet is anything that is attracted to certain kinds of metal. This makes a force that either pulls towards or pushes away from something based on certain properties. Magnetism is the force between two different things that pulls together or pushes apart. What scientists know about magnets has led to technology being created that has changed our everyday lives. For one, the cell phone wouldn't have been possible without using magnets. Let's talk about magnets and how they work.

Magnets come in various shapes, sizes, and strengths.
OpenStax, CC BY 4.0 , via Wikimedia Commons


Magnets
The earliest records of magnets date to a region of Asia called Magnesia.  These rocks began the growing interest in magnets during ancient times. A day to day use for magnets began when they were used as part of compasses to tell people direction. The use of magnets in compasses didn't only lead to better ways to sail far away, but also in the names of "north" and "south" being given to the two kinds of magnetic poles. The reason why a compass works has to do with the Earth and very large magnetic forces, which scientists believe come from the thick, high-energy matter found in the Earth's center. We will talk more about this in time.

All magnets attract iron, found in many refrigerator doors, which is why they can be used to hold papers to the fridge. On the other hand, magnets may also push toward or pull against other magnets, and the way in which this happens can be copied to make the same thing happen every time. Experimentation shows that all magnets have two poles. A pole is one of the two sides of a magnet where the force of magnetism is strongest. If left alone by itself, one pole of a magnet will point toward the north of the Earth, and the other will face the south of the Earth. This is why the two poles are named the north magnetic pole and the south magnetic pole.
One end of a bar magnet is suspended from a thread that points toward north. The magnet’s two poles are labeled N and S for north-seeking and south-seeking poles, respectively.
OpenStax, CC BY 4.0 , via Wikimedia Commons


Magnetic Behavior
All magnets behave in a predictable way, which you can see for yourself if you take two magnets from the refrigerator and try a quick test to look at how things work. One orientation of the magnets will make a different force than if you flip one of the magnets to its other side. When like sides, such as two south magnetic poles of two magnets, are near each other, they will repel. To repel means two things push away from each other. Opposite sides of two magnets, such as the north magnetic pole of one and the south magnetic pole of another, will attract. To attract means that two things pull towards each other.  Something all magnets share and do is that like poles repel and unlike poles attract. You can watch this if you take two strong magnets and try to force like sides together. What happens is one or both of the magnets pushes away with such a great force that you may not be able to join them together!
Opposite poles will attract each other.
Modified from OpenStax Physics


A compass is one familiar and useful application of magnets. The magnet in a compass can used to demonstrate the direction you are going based on the way the magnet points. To understand how this works, we need to clarify that the word "pole" can be used in two different approaches. It can be used to describe the two opposite sides of Earth in a geographic sense. It can also be used to describe the opposite end of magnets. A compass arrow will always point towards the north of the Earth. The Earth acts like a very large bar magnet, but not in the way that you'd think! The geographic North Pole really behaves like the south pole of a giant magnet! The north pole of your compass magnet is pulled toward the geographic North Pole of the Earth - which is a very different pole. This is because the magnetic pole that is near the north of the Earth's Pole is a south magnetic pole! This gets the confusing because the geographic term "North Pole" has come to be used incorrectly for the magnetic pole that is near the North Pole, instead of just the geographic place on Earth. So, "North magnetic pole" is really the wrong way to describe the magnetic pull at the North Pole of the Earth - it should really be called the South magnetic pole.
Poles that are the same will repel each other.
Modified from OpenStax Physics


Something interesting about magnets is that their two poles perpetually stay the same relative to each other. If you take a bar magnet and break it in half, you will get two new magnets. The first magnet has a south pole and a north pole, but each new magnet that you make by breaking the first one will have both a south pole and a north pole, too. If we continue to split the magnet, we will over time get down to a single iron atom with a north pole and a south pole - these, too, cannot be divided.

Temporary and Permanent Magnets
Only certain metals show strong magnetic effects. Others have weak magnetic effects, which can only be picked up if you have the right tools. From time to time, a strong magnet can "lend" its magnetic powers to weaker magnets. You may have seen this if you have ever used a magnet to pick up something small and metal, like a nail. The first item that is attracted to the magnet can then attract other like things. You can make a fairly long chain of nails with only a single magnet! These are temporary magnets because they aren't always magnets, which is different than permanent magnets. 
Engineering of technology like iPods would not be possible without a deep understanding magnetism.
Jesse! S?, Flickr.com


Magnets in our World
All electric motors, like those found in electric cars, work because of magnets. Recycling facilities use huge magnets to separate iron from other refuse. Magnetic resonance imaging, or MRI, has become an important tool in the field of medicine to learn about the inside of the body, and the use of magnets to look at the way the brain works is a subject of research today. The list of uses for magnets also includes computer hard drives, finding inhaled pollutants, and making better trains. All of these different uses are connected by the simple and clear rules that govern what magnets do.

References

Adapted by the RocketLit Team from:

License

CC BY 4.0