First law of magnetism
Natural magnets
Application of magnets
History of magnetism
Compass
Magnetic field
Magnetic force
Magnetism-Forces of play
I have come across magnets, but what really are magnets?Unlike stone, wood, or gold magnets have a magnetic force around them. Force is associated with energy; through force energy can be converted from once source to another. Note in Figure 1 that force lines are directed from North pole to South pole.
What are poles?
Any object has two sides: up, and down or north and south as in Figure 2. For magnets the poles have attractive and repelling tendencies. I am sure that you have played with magnets, and aware that the like poles repel, and opposite poles attract (Figure 3).
Who discovered magnets?
Early civilization of China, Greek, and India appear to be aware of magnets. Chinese are credited with using magnets to tell directions as early as C.E. 1200?. An extensive and visual account of the history of magnetism or "magnetism through the ages" is e-published at
http://www.tcd.ie/Physics/Schools/what/matrerials/magnetism/one.html
Do magnets occur naturally?
Magnets do occur naturally, but most are manufactured today.
How do you explain magnetic field found in natural magnets? Is it a chemical property?
Magnet is not an element. Magnetic substance such as iron, steel, nickel, and cobalt become magnetized. Note that magnetic substances are minerals that are attracted to magnets when placed within adequate distance or the magnetic field of the magnets.
Natural magnets or loadstones as referred in earlier times "are rich in magnetite, an iron oxide mineral. Lightening with a typical current of 1,000,000 Amps creates a magnetic field large enough to saturate the magnetization of nearby loadstone outcrops. This is a rare event-on average lightning strikes that close to any point on the Earth's surface happens once in a 1-10 million years." This is according to http://www.tcd.ie/Physics/Schools/what/matrerials/magnetism/one.html
Are natural magnets found in abundance on earth?
I assume not, because we are manufacturing most of the magnets.
How are magnets manufactured today?
What is the physics theory behind?
What are the alternative theories?
What are magnets useful for?
Magnets or magnetic forces or an understanding of the electromagnetic waves is essential for modern living. Compasses, motors, generation and transmission of electromagnetic energy, radio, television, computer and all other products use magnets directly and are dependent on the understanding of the magnetic properties.
You stated that magnetic force associated with magnets as the defining property of magnets. Does the existence of magnetic force, imply that magnets posses a special form of energy - magnetic energy?
In some sense, yes! Think of a book sitting at a height, it posses potential energy due to its position with respect to some lower position. Similarly, magnets or magnetic field has energy. The trouble is in harnessing that energy to do useful work for us.
What do you mean by magnetic field?
Surrounding the magnetic bar there exists magnetic filed or forces. One can see this (Figure 4) if one sprinkles magnetic material dust; they organize themselves along the lines of force or flux lines. Magnetic field is the region where magnetic force exist.
What is the difference between magnetic field and magnetic force?
Magnetic field is the region where magnetic force exists.
Is the magnetic force only exist along the lines of force?
I do not think so. The force is distributed in space, but we visualize using lines of force. Also note that:
Does the strength of the magnet depend on the size of the magnet?
How do we measure the strength of the magnetic force?
How can we harness the magnetic energy to do useful work?
Does the magnetic energy get depleted after use?
Above are all interesting questions for which I do not have through answers. I do know that the strength of the magnetic field does not depend on its size, rather the type of material and production process. Also, a magnetic substance such as iron or nickel can become magnetic if charges flows (current) through the material, or near it.
You mean electric current causes a magnetic substance to be magnetized?
(Continuous Question)