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What Are Magnetic Forces?

A horseshoe magnet with north and south poles labeled.
Refrigerator magnets.
The Earth has a planetary magnetic field.
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  • Written By: James Doehring
  • Edited By: Lauren Fritsky
  • Last Modified Date: 20 September 2014
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    Conjecture Corporation
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Magnetic forces act upon magnetic objects or charged particles moving through a magnetic field. They are affected by the strength of the magnetic field, the total charge of a particle, and its speed and direction. Permanent magnets have their molecular structures aligned during formation so that they will attract certain types of metals. Magnetic forces are exploited when electricity is converted to mechanical rotation, and vice versa.

The medium through which these forces are transmitted is the magnetic field. A magnetic field is created with a permanent magnet or an electric current. Since an electric current is a stream of moving charge carriers, such as electrons, it can be analyzed by considering only one particle. Thus, a single electron moving through space will create a magnetic field.

One common application of magnetic forces is the refrigerator magnet, which is a permanent magnet. Permanent magnets are subjected to a strong magnetic field when they are manufactured. In this process, their internal crystalline structures are aligned such that they remain magnetized. A permanent magnet will attract ferromagnetic materials such as iron. Ferromagnetism is only one source of magnetic forces, but it is the one commonly associated with magnetism in everyday situations.

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Permanent magnets also exert magnetic forces on other magnets. This is when the magnets’ poles become important. Unlike electric field lines, magnetic field lines always circle around and form a closed loop. In other words, magnets always have two distinct poles, conventionally called a north and south pole. The same poles of two different magnets will repel, while opposite poles will attract.

Another situation where magnetic forces will arise involves two neighboring electric currents traveling at right angles to each other. These currents will produce their own magnetic fields, but they will be in different orientations, leading to forces between the two currents. The more current there is, the stronger the forces will be.

The interaction between magnets and an electric current is the basis of both the electric generator and the electric motor. For a generator, mechanical motion produced by a power plant or engine spins a component with magnets on it. The changing magnetic field will induce an electric current in the other part of the generator. When the device is used as a motor, it is the electric current that is supplied. The same magnetic forces will produce a mechanical torque to spin the other side of the motor.

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orangey03
Post 7

I take advantage of magnetic forces whenever a spill a box of paper clips or staples at work. I have learned to keep a magnet on my desk for easy cleanup.

I am accident prone, and it seems that every time I reach for a paper clip, I end up knocking over the entire box onto the floor or all over my desk. Also, on more than one occasion, I have dropped a set of staples on the floor and broken it into its tiny counterparts.

All I have to do is swipe the rectangular magnet low over the area, and all the mess returns to me. It saves a lot of time.

seag47
Post 6

My dad is always using his metal detector while trying to find old coins or jewelry on beaches. One day, I asked him how it worked, and I was surprised to learn that magnetic force is involved.

He told me that the metal detector transmits a magnetic field. When the electric currents hit a metal object, it disturbs the field. That’s when you hear the dinging sound, which varies according to what metal composes the object.

So far, he has yet to find any buried treasure. He has found a few old pennies and dimes to add to his collection, thanks to magnetic forces.

lighth0se33
Post 5

Magnetic forces are responsible for the aurora borealis. I would love to see the northern lights at least once in my lifetime. I have read a lot about them.

The northern lights show up when the super charged electrons of winds from the sun react with our atmosphere. When these electrons get to our planet, they are drawn to the areas of magnetic force produced by the core of the earth. So, they flow through the part with the strongest charge.

Depending on the altitude of the molecules they interact with, different colors will appear. Green, purple, and red are common. Every photo or video of the lights that I have seen has included bright green.

shell4life
Post 4

My husband works with metal in his shop a lot. When he uses a machine to cut it, he winds up with a lot of metal shavings on the floor. We have a dog and a two-year-old daughter, so this could potentially be dangerous.

To keep their feet from getting cut, he uses a magnet to pick up the shavings. The attraction is strong enough to pull the pieces off the floor. The magnet will pick up even the tiniest pieces that he might miss, because they are very hard to see.

lluviaporos
Post 3

@irontoenail - There are some thing that haven't been wholly understood yet by science. I know a few people who really do think using magnets has helped them with their pain. Maybe it is only the placebo effect.

But, in their cases at least, it was worth the money that they paid. Maybe magnetic lines of force aren't a magical cure all, but I think people should be able to make up their own minds about it.

irontoenail
Post 2

I actually think one of the most common uses of magnets these days is to take money off people.

There are all kinds of health claims about magnets that have never been proved, but people will spend a lot of money trying to reap the benefits from a magnetic force field or something.

I know that they sell bracelets and blankets with magnets woven into them, and tell people they will help them sleep better, or make their arthritis go away.

It just makes me a bit mad, because often it is people who can't afford the proper cure who shell out money to buy something that won't really help them.

browncoat
Post 1

My grandmother used to collect fridge magnets. She would get a handful almost every time I was there, and ended up with a fridge that was more magnet than white!

Us kids would play all kinds of games with them, especially as some of them were shaped like animals or people and we could pretend they were fighting, or falling in love, or going shopping even.

I was also fascinated by the magnet itself, and how they would repel each other if I tried to stick them together. It seemed almost like magic to me.

I think I would do the same for my grand kids when I have them. It was a great way to distract us so granny and my mother could have a cup of tea together.

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