This is a drawing of a magnetic field.
Click on image for full size
The Magnetic Field
The force of magnetism causes material to point along the direction the magnetic force points. As shown in the diagram to the left, the force of magnetism is illustrated by lines, which represent the force. In this diagram, the force points from the positive pole to the negative pole of the magnet. As shown in the diagram, if one side of the magnet is called the positive side, and the other side called the negative side, the force of magnetism flows from the positive side or pole, to the other pole. Here's another picture of how this works.
The force of magnetism forces small pieces of iron to line up in the direction the magnetic force points. A compass, in which a sliver of magnetic material can swing freely, is thus forced to point toward the positive pole.
On Earth, the north (positive) pole of the Earth's magnet is in fact at its South geographic pole. A compass needle sure enough indicates North, but if you put a compass needle near a bar magnet, it points AWAY from the north (positve) pole of the bar magnet. This picture shows where the poles are actually found, and also shows that the poles drift over the surface of the Earth over time.
The force of magnetism coming from the magnet is called the "magnetic field", and is illustrated by lines. The magnetic field is strongest where the lines of force come together (and turn red), and is weakest when the lines of force are far apart (and turn blue).
Shop Windows to the Universe Science Store!
Our
online store includes
books on science education,
classroom activities in The Earth Scientist,
mineral and
fossil specimens, and
educational games!
You might also be interested in:
This very special issue of The Earth Scientist (our biggest ever!) is sponsored by the Cooperative Institute for Climate and Ocean Research at the Woods Hole Oceanographic Institution and is focused on the world’s oceans.
...more
The Sun has a very large and very complex magnetic field. The magnetic field at an average place on the Sun is around 1 Gauss, about twice as strong as the average field on the surface of Earth (around
...more
Sunspots are caused by very strong magnetic fields on the Sun. The best way to think about the very complicated process of sunspot formation is to think of magnetic "ropes" breaking through the visible
...more
Some particles do move along the field lines of the Earth. The crowded magnetic field lines near the poles cause particles to "reflect" and move back the same direction the from which they came. They bounce
...more
Magnetic fields can cause particles to move in these three ways: Spiral Motion Bounce Motion Drift Motion
...more
Protons and electrons can't move across magnetic field lines very easily. So sometimes these particles are are forced to spiral around them. Electrons cirle the field line in one direction, protons in
...more
Unlike the Earth, which has a protective shield around it called the magnetosphere, the surface of the moon is not protected from the solar wind. This picture shows the magnetosphere surrounding the Earth,
...more
The solar wind is formed as the Sun's top layer blows off into space, carrying magnetic fields still attached to the Sun. Gusts form in the solar wind associated with violent events on the Sun. Particles
...more
