Magnetism

The link between electricity and magnetism finds its legendary roots back to Hans Christian Orsted when he supposedly found that electric current affected his compasses during a student lecture. That piece of scientific history may be one of exaggerated legend, but the marriage of electricity with magnetism has been widely known for over a century, later to be given a full mathematical explanation by Lord Kelvin and James Clerk Maxwell. The concept of electron movement causing the production of an ensuing magnetic field is a fundamental model used in describing electromagnets, generators, transformers and electric motors.

In 1820, Danish physicist/chemist Hans Christian Ørsted noticed that when current from his Voltaic pile was switched on and off, a compass needle placed near the wire deflected from true magnetic north. Within a few months of careful study, he deduced that a magnetic field circles a current-bearing wire.

One of the first science toys I ever owned was a water rocket. Essentially a plastic container with fins, the rocket is prepared for flight by partially filling it with water and pressurized air. When released, the rocket’s contents exit a small hole at the base of the rocket in one direction, pushing the rocket ahead with amazing speed in the opposite direction. A case of action-reaction, pure and simple.

A mystery to the ancients and a marvel to Einstein, magnetism is inextricably linked to the operation of motors and generators, the functioning of radio, television and computers, and our understanding of the universe. From the Greeks, who found that certain stones would attract pieces of iron, to Einstein who, as a child, was captivated by the mysterious properties of magnets, humankind's fascination with magnetism has never abated.