|James Clerk Maxwell (1831-1879)|
James Clerk Maxwell, a Scottish physicist and mathematician, is generally regarded as one of the world's greatest physicists. Maxwell's researches combined the fields of electricity and magnetism and introduced the concept of the electro-magnetic field. Following James Clerk Maxwell's research, we now call a space modified by the presence of magnetic field lines a "magnetic field": if a bar magnet is placed there, it will experience magnetic forces, but the field exists even when no magnet is present. Similarly, an "electric field" is the space in which electric forces may be sensed--for instance between metal objects charged ( ) and (-) by a battery, as in the drawing accompanying the discussion of the electron.
In 1864, James Clerk Maxwell demonstrated a subtle connection between the two types of force, unexpectedly involving the velocity of light. James Clerk Maxwell showed that an "electromagnetic wave" was possible, a rapid interplay of electric and magnetic fields spreading with the velocity of light. Maxwell correctly guessed that light was in fact such a wave, that it was basically an electromagnetic phenomenon, and with this his equations paved the way to a much deeper understanding of optics, the science of light. He further showed that electric and magnetic fields travelled through space, in the form of waves, at a speed of 3.0 × 108 m/s. He thus argued that light was a form of electromagnetic radiation.
James Clerk Maxwell predicted the existence of radio waves. From this connection sprang the idea that light was an electric phenomenon, the discovery of radio waves, Einstein's theory of relativity and a great deal of present-day physics.
Photo Courtesy of NASA