If you take a bar magnet and break it in half, you end up with two smaller bar magnets. If you break the halves into fourths, you get four small bar magnets. If you have enough patience and time you can repeat this until you have millions of microscopic magnets.
All magnets have two poles; a north pole and a south pole. We call this a dipole (two poles). Two north poles or south poles repel each other. Try forcing the two north poles of two bar magnets together. The unseen magnetic field makes it feel like there's a water balloon between them resisting your push. Opposite poles (a north and a south) attract strongly.
Some molecules, some atoms, and all electrons are little magnets. So why isn't everything magnetic? In most matter, the molecules, atoms, and electrons are all jumbled up together. In a strong magnet, most of the little magnets (magnetic domains if you want to get fancy) point in the same direction. This makes the magnetic force of all the little magnets add up to make a large magnet, called a permanent magnet.
Free magnets tend to align with each other. You can try this by placing one magnet on a table and slowly moving another magnet toward it. The magnet that is loose on the table turns to align with the magnet in your hand. If you stroke a piece of iron with a magnet, you gradually align the little magnetic domains, and the result is a larger magnet.
Electric current is the flow of electrons through a conductor. A conductor is a material that lets the electrons hop from atom to atom when influenced by an outside force. If you move a wire (which is an electric conductor) through a magnetic field, you force (induce) the electrons to travel in one direction through the wire. Electrons flowing through a conductor create a magnetic field around the conductor. This is called electromagnetism.
Many different substances can be made into permanent magnets. However, for all these materials, there is a critical temperature called the Curie point. At this temperature or above, the molecules within the material are moving around too much for the material to retain the magnetic alignment necessary to exhibit a magnetic field.
Earth's magnetic field is very complicated. It can be thought of as being one large magnetic dipole with twelve more small magnets arranged at various angles.
A curious fact about Earth's magnetic field is that it is not lined up with the spin axis. Its alignment is about 11 degrees off the axis defined by the north and south poles. (Without knowing this, you can't find the North pole using only a compass!)
The magnetic field shields us from much harmful radiation. Cosmic rays come from all directions, and the sun sends out a steady stream of high-energy particles known as the solar wind.
Genesis 1:6 describes the firmament (Hebrew raqia) separating the water below from the water above. Before the flood described in Genesis, the magnetic field may even have helped to suspend the firmament above the earth.
This presents a significant problem for evolutionists and their belief in a 4.6-billion-year-old earth. Their answer is the dynamo theory, which assumes that the core of the earth is made of molten metal (iron-nickel mixture). Molten material inside the earth is far hotter than the Curie point, which means that the earth as a whole is not a permanent magnet; it must be an electromagnet. The dynamo theory is that slow, internal convection currents or planetary rotation generates the magnetic field, and that this mechanism has operated for the assumed 4.6 billion years. Since This theory also claims that the field reverses over extremely long periods of time.
As sediment accumulates or as molten rock cools, the earth's magnetic field is believed to have aligned the magnetic domains within the material as it hardened, locking in a record of the orientation of the geomagnetic field at the time. Measurements of the magnetic-field polarity in ancient volcanic lava flows show that Earths magnetic field gyrated wildly at one point in time. Other evidence for a change is that the residual magnetic fields in rock formed on the ocean floor where the great tectonic plates are pulling apart show a number of different orientations. The traditional assumption here is that these processes went on at the same rate in the past as we observe today. However, during the flood, when cataclysmic geologic events were occurring at a rapid pace, these processes may have been recording what happened to the magnetic field over weeks or months instead of hundreds of thousands of years.
Dr. D. R. Humphreys has studied the physical evidence of magnetic-field reversal and decay and developed a model that describes the magnetic field as having a high initial strength, a series of rapid reversals during the flood year, slower variations until the time of Christ's earthly ministry, then gradual steady decay.
The idea that the geomagnetic field could have rapidly reversed was rejected by the evolutionary community, even though a much larger body, the Sun, reverses its field every eleven years.
Recent discoveries have added more weight to Dr. Humphreys model. The April 5, 1995 edition (Vol. 14) of Science News reported on a Nature article that researchers are finding fresh evidence of extremely-rapid field orientation shifts, as much as six degrees per day. The article states that ``if that happened today, compass needles would swing from magnetic north toward Mexico City in little over a week''. The article quotes one geophysicist as saying ``that shows the core to be violently active in terms of the magnetic field''.
Violently active? ``...on that day all the fountains of the deep were broken up...'' Genesis 7:11, NKJV.
``He who was sat on the throne said `Behold, I make all things new!'''... Revelation 21:5, NKJV.