Since ancient times people have known that certain kinds of rocks found in the ground have the ability to attract or pull toward metal. These rocks are called lodestones. Over the centuries scientists learned that the property that made lodestones attract metal was called magnetism. They then learned how to make their own artificial lodestones, called magnets. Today magnets are used for many purposes: from holding refrigerator doors closed to storing information in computers and building machines to study the secrets of the universe and the human body. - A basic law of magnetism is that unlike poles attract each other. Two bar magnets can illustrate …
- A basic law of magnetism is that like poles repel each other.
Magnetism, like electricity and gravity, is a basic force of nature. Scientists have known for a long time that electricity flowing through a wire creates a magnetic force around the wire. They also know that all objects in the universe are made up of atoms, which are extremely tiny collections of particles called electrons, neutrons, and protons. The electrons spin around the nucleus of the atom, which contains the protons and neutrons. Electrons moving around protons have the same effect as electrons moving through a wire, which is exactly what electricity is. Therefore atoms create tiny magnetic forces, like electricity does in wires. When all of the atoms in an object have their electrons spinning around their protons in the same direction, all the tiny magnetic forces from the atoms add up to make the object one big magnet. In other words, magnets are simply objects whose atoms have electrons all rotating around their protons in the same direction. |