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Name: Glenn
Status: student
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Question:
While writing a unit on magnets, I was asked, well you need to define magnetism and establish general understanding. The facts are easy to list but what is magnetism? I wrote that it was a form of energy that has specific properties and characteristics. Well how accurate am I? Is it a form of energy or just a "force".


Replies:
Dear Glenn,

You have opened a great can of worms! Magnetism is a force that is interrelated with electricity. I am assuming that you are looking for explanations geared towards primary grades. May I recommend this website?

www.explainthatstuff.com/magnetism.html

It is a good website with basic information. You can look at your benchmarks for primary grade science to determine how much you need them to understand. It also lists a few books for further reading at the end. One of the books has experiments that your kids might enjoy doing. Let me know if this is enough to get you started. If not, e-mail back with the primary benchmarks and I'll see if I can help you out a little more.

Good Luck,

Martha Croll


Glenn

You can find your answer by going to http://www.google.com and searching for "Magnetism". There are a number of tutorial web pages written at all kinds of levels.

I get my best information from Wikipedia. It is an open source on-line encyclopedia that is reviewed and edited by super experts in the field. So when I "Google wiki" I get this:

http://en.wikipedia.org/wiki/Magnetism

This site describes magnetism this way:
"Magnetism is a category of behaviour of materials that respond at an atomic or subatomic level to an applied magnetic field."

Yours is a complicated question. I do not think it is accurate to say that magnetism is an energy. Energy is the "capacity to do work." http://en.wikipedia.org/wiki/Energy

http://en.wikipedia.org/wiki/Work_(physics) defines work as a delta energy.

In the wiki.magnetism article, in the "Magnetic Fields and Forces" Section, we see this:

"When a charged particle moves through a magnetic field B, it feels a force F given by the cross product:

F = q (v X B)

where

q is the electric charge of the particle,
v is the velocity vector of the particle, and
B is the magnetic field.

Because this is a cross product, the force is perpendicular to both the motion of the particle and the magnetic field. It follows that the magnetic force does no work on the particle; it may change the direction of the particle's movement, but it cannot cause it to speed up or slow down. The magnitude of the force is

F = q v B sin(è),

where è is the angle between v and B."

Since magnetism cannot speed up or slow down a particle (0 delta energy), the best we do to define magnetism is as a "category of behavior of materials at an atomic or sub-atomic level..."

This site calls Magnetism a Force, but I cannot agree with that because a bar magnet that displays the characteristics of magnetism does not exert a force on anything if it is not in the magnetic field. http://www.school-for-champions.com/science/magnetism.htm

Sincere regards,

Mike Stewart


You asked one of those questions that appears "simple" to ask but very tough to answer in "simple" terms. As you point out, you can list the facts of how it behaves, but absent from that list is a simple explanation of "What it is." I tried a search using the search term: "What is magnetism?" I too found a lot about how it behaves but very little about why it behaves the way it does. This problem is not unique to "magnetism". There are a lot of such terms. For example: gravity, electrical charge to name a couple. Science is good at explaining "how things work" but not so good at "what it is." I'll keep looking but I didn't want you to think you were being ignored. You just asked a very hard question.

Not a simple answer but a good resource is the NASA website:

http://www-istp.gsfc.nasa.gov/Education/wmfield.html

Vince Calder


Hi Glenn

I think we must talk a bit in order to answer your question. First the scientists discovered that there are 4 forces known that sustain the universe called:
1. Gravity - This force acts between all mass in the universe and has infinite range.
2. Electromagnetic ­ This one occurs between electrically charged particles. Electricity, magnetism are effects produced by this force that also has infinite range.
3. The Strong Force - This force binds neutrons and protons together in the cores of atoms and is a short range force.
4. Weak Force -Like the strong force, the weak force is also of short ange. It is present inside the atom and it is related with radioactivity, conversion and/or formation of different particles inside the atom nucleus.

So when you speak of magnetism or electricity you rather say “Electromagnetism” that results from the presence of an electromagnetic force.
Electromagnetism, also called electromagnetic interaction, or electromagnetic force is a long-range force involving the electric and magnetic properties of elementary particles. Particles with the same charge repel to each other and are attracted when have opposite charges. It explains atomic structure (positive protons and negative electrons) and the properties of light and other forms of electromagnetic radiation. Its effects are easily observed such as light and heat. Magnetism occurs when materials exert an attractive or repulsive force on other materials, as a magnet.

Electricity is related to charges, and both electrons and protons carry a charge. The amount of the charge is the same for each particle, but opposite in sign. Electrons carry a negative charge while protons carry positive charge. The protons are basically trapped inside the nucleus and can't escape .As a result, it is moving electrons that are primarily responsible for electricity.

Answering your question:
electromagnetism is a Force not Energy. But is is also actually a secondary energy source, also referred to as an energy carrier. That means that we can get electromagnetism from the conversion of primary sources of energy, such as coal, nuclear, or solar energy.

Thanks for asking NEWTON!
Mabel
Dr. Mabel Rodrigues


Glenn--
You are hitting at some interesting material. There is much confusion between energy and force. Simply put, force is a push or pull, while energy is a conserved quantity that flows when there is a change.

Contrary to what is commonly written about energy, there is only one kind of energy: energy. It is all measured in joules. We describe energy by its location. For example, if we lift a book from a table into the air, the energy transferred from us to the gravitational field. We can describe this by U=mgh. If the object is moving, we call it kinetic energy (energy stored in the motion of the body) and is described by the equation K=(1/2)mv^2.

Force is not a conserved quantity. When the force is no longer applied, it is not transferred anywhere else, it just ceases to exist. This never happens with energy.

Magnetism is a field that can exert forces on objects. This, in turn, can result in a transfer of energy into or out of the magnetic field.

There are many web sites that address or identify science misconceptions. Here are a few:

http://www.darylscience.com/Misconceptions.htm

http://www.physicstutorials.org/index.php/home/mechanics/1d-kinematics/misconceptions

http://www.eskimo.com/~billb/miscon/opphys.html

http://phys.udallas.edu/C3P/Preconceptions.pdf

http://dese.mo.gov/divimprove/curriculum/science/SciMisconc11.05.pdf

http://homepage.mac.com/vtalsma/syllabi/2943/handouts/misconcept.html

There are many other sites in the Physics Education Research and Science Education Research. Frankly, you may harbor some of these misconceptions. I know I still harbor some. Teach the best you can while you learn about the misconceptions and try to devise strategies to confront them. I know that I

have taught misconceptions, and I work diligently to uncover my own misconceptions to better serve my students. I encourage you to keep on learning!

---Nathan A.Unterman



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