The Science Teacher: Earth Science

The Earth's magnetic field has a north and a south just like a regular bar magnet, but I had already been a teacher of science for many years when the exact nature of North and South became more important to understand. I was interested in how the magnetic field of the Earth has switched over the millions of years. Scientists can actually prove many such reversals and can even point to spots on the Earth where such a reversal is already started again. The exact process by which this occurs is not understood, but the core of the Earth is composed of a liquid iron and nickel mixture that is rotating and it is this rotation that has been suggested as causing the magnetic field. It is not that great a stretch to imagine that this mixture can completely switch and cause the magnetic field to reverse. Fortunately for us, this is not likely to occur for at least several thousand years. From the research it appears that such reversals can occur quite quickly when in the final stages.

In my review of this, it came to my attention that what we call the North Pole is actually a "South Magnetic" pole. When we use a compass to point toward the North, the needle on the compass is pulled along magnetic lines. Opposites attract in magnets. This would mean that the needle on the compass would have to be either labeled incorrectly, in other words the "N" would have to be on the south side of the magnetic pole of the needle so the needle would be pulled toward the opposing north, or the needle would have to be labeled correctly as a "N" for north and then being attracted toward an opposite south magnetic pole. As it turns out the needle on the compass is labeled correctly and it is being pulled in a north direction because it is attracted to a south magnetic field at our north pole.

We are not going to change our designation of the North Pole however, we wouldn't want to upset the children of the world saying that Santa actually is at a South Magnetic Pole and since it should be thousands of years before there is another complete magnetic reversal it is not likely we will worry about that soon, but as a science teacher I feel better understanding the true nature of our "North" pole and will of course make every effort to pass on accurate information to my students.

The study of magnetic fields is very important to many types of scientists and many scientists would love to discover the exact connection between all the forces of nature including magnetism.