Who Discovered Electromagnetism and How does an electric current create a magnetic field?

Before 1820, the only known magnetism was the naturally occurring magnetism of iron magnets and of lodestones, small, weak direction finders.

Yet the modern world of electric motors and electric generating power plants is muscled by powerful electromagnets. So is every hair dryer, mixer, and washing machine. Our industry, homes, and lives depend on electric motors, which all depend on electromagnetism.

This 1820 discovery has become one of the most important for defining the shape of modern life. Hans Oersted’s discovery opened the door to undreamed of possibilities for research and scientific advancement. It made possible the work of electromagnetic giants such as Andre Ampere and Michael Faraday.

Hans Oersted was born in 1777 in southern Denmark. He studied science at the university, but leaned far more toward philosophy. Oersted adopted the philosophy teachings of John Ritter, who advocated a natural science belief that there was unity in all natural forces. Oersted believed that he could trace all natural forces back to the Urkraft, or primary force. When he was finally given a science teaching position (in 1813), he focused his research efforts on finding a way to trace all chemical reactions back to Urkraft in order to create a natural unity in all of chemistry.

Research and interest in electricity mushroomed after Benjamin Franklin’s experiments with static electricity and sparks of energy created with Leyden jars. Then, in 1800, Volta invented the battery and the world’s first continuous flow of electric current. Electricity became the scientific wonder of the world. Sixty-eight books on electricity were published between 1800 and 1820.

Only a few scientists suspected that there might be a connection between electricity and magnetism. In 1776 and 1777 the Bavarian Academy of Sciences offered a prize to anyone who could answer the question: Is there a physical analogy between electrical and magnetic force? They found no winner. In 1808, the London Scientific Society made the same offer. Again there was no winner.

In the spring of 1820, Hans Oersted was giving a lecture to one of his classes when an amazing thing happened. He made a grand discovery, the only major scientific discovery made in front of a class of students. It was a simple demonstration for graduate-level students of how electric current heats a platinum wire. Oersted had not focused his research on either electricity or magnetism. Neither was of particular interest to him. Still, he happened to have a needle magnet (a compass needle) nearby on the table when he conducted his demonstration.

As soon as Oersted connected battery power to his wire, the compass needle twitched and twisted to point perpendicular to the platinum wire. When he disconnected the battery, the needle drifted back to its original position.

Each time he ran an electric current through that platinum wire, the needle snapped back to its perpendicular position. Oersted’s students were fascinated. Oersted seemed flustered and shifted the talk to another topic.

Oersted did not return to this amazing occurrence for three months, until the summer of 1820. He then began a series of experiments to discover if his electric current created a force that attracted the compass needle, or repelled it. He also wanted to try to relate this strange force to Urkraft.

He moved the wire above, beside, and below the compass needle. He reversed the current through his platinum wire. He tried two wires instead of one. With every change in the wire and current, he watched for the effect these changes would produce on the compass needle.

Oersted finally realized his electric current created both an attractive and a repulsive force at the same time. After months of study, he concluded that an electric current created a magnetic force and that this force was a whole new type of force, radically different than any of the forces Newton had described. This force acted not along straight lines, but in a circle around the wire carrying an electric current. Clearly, he wrote, wires carrying an electric current showed magnetic properties. The concept of electromagnetism had been discovered.

The aurora borealis, or “northern lights,” are an electromagnetic phenomenon, caused when electrically charged solar particles collide with Earth’s magnetic field. In the Southern hemisphere these waving curtains of light form around the south pole and are called the aurora australis, or “southern lights.”