Electromagnetic Radiation/
Radio Waves
Year of Discovery: 1864
What Is It? All electric and magnetic energy waves are part of the one electromagnetic spectrum and follow simple mathematical rules.
Who Discovered It? James Clerk Maxwell
Why Is This One of the 100 Greatest?
Throughout most of the nineteenth century, people thought that electricity, magnetism, and light were three separate, unrelated things. Research proceeded from that assumption. Then Maxwell discovered that they are all the same—forms of electromagnetic
radiation. It was a startlingly grand discovery, often called the greatest discovery in physics
in the nineteenth century. Maxwell did for electromagnetic radiation what Newton did for
gravity—gave science mathematical tools to understand and use that natural force.
Maxwell unified magnetic and electrical energy, created the term electromagnetic radiation, and discovered the four simple equations that govern the behavior of electrical and
magnetic fields. While developing these equations, Maxwell discovered that light was part
of the electromagnetic spectrum and predicted the existence of radio waves, X-rays, and
gamma rays.
How Was It Discovered?
James Clerk was born in 1831 in Edinburgh, Scotland. The family later added the
name Maxwell. James sailed easily through his university schooling to earn top honors and
a degree in mathematics. He held various professorships in math and physics thereafter.
As a mathematician, Maxwell explored the world—and the universe—through mathematic equations. His chose the rings of Saturn as the subject of his first major study.
Maxwell used mathematics to prove that these rings couldn’t be solid disks, nor could they
consist of gas. His equations showed that they must consist of countless small, solid particles. A century later, astronomers proved him to be correct.
Maxwell turned his attention to gasses and studied the mathematical relationships that
governed the motion of rapidly moving gas particles. His results in this study completely revised science’s approach to studying the relationship between heat (temperature) and gas
motion.
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