The force that attracts or repels at a distance is called magnetism, and is due to a magnetic field that is caused by moving electrically charged particles. Magnets have two opposing poles, and the flow of electrons from one pole to the other is what causes a field. This flow of electrons is called the lines of flux.
One thing that is really cool about fields, is that it is still a mystery just exactly what they are made up of, but we do know that it is a special property of space! If two objects with magnetic fields come near each other, they can create a force. This force is called magnetism. Depending on whether the poles of two objects are like (N, N) or dislike (N, S) they will either repel or attract respectively.
To demonstrate the differences I am using a liquid with magnetic properties known as Ferro fluid, and three neodymium magnets with insulators in between them.
Here is one of the best examples of a "force" field your likely to see...since like gravity it is invisible! Something to keep in mind when out in the field using a Tri-Field Meter.