A while back I started a series of pieces about "things electrical." Published to date are entries titled

• "A drift of electrons"
• "Sweet induction"

This is the third installment.

When I first started studying electronics, I came across this statement in my textbook and was intrigued:

A charged particle moving in an electric field generates magnetism.

Searching on "charged particle in electric field", I couldn't find this statement anywhere to verify that I remembered it correctly. Then I remembered my son's series of books on science.

In 1819, a Danish scientist, Hans Chrisian Oersted, discovered electromagnetism. Oersted found that a nearby compass needle would move each time he switched some electrical equipment on or off. Normally, the needle pointed in a north-south direction. But, when Oersted switched on his equipment, the needle swung around to point in a different direction. It returned to its original position when the equipment was switched off.

Oersted found that the effect was caused by the electric current flowing through a wire near the compass. For some reason, the wire acted like a magnet when the current flowed through it. ... Oersted had discovered electromagnetism, although he did not discover why electricity should give rise to magnetism. In fact, even today, scientists do not understand electromagnetism fully...

Growing Up with Science: vol.5, "Electromagnetism;" H.S.Stuttman; 1987
[I've omitted a lot of the repetition--it's a children's book, after all.]

As far as I'm concerned this answers my guery. But, during my search, I found other information that is also intriguing. One interesting reference to Einstein's paper "On the Electrodynamics of Moving Bodies" in the wikipedia states that it

...reconciles Maxwell's equations for electricity and magnetism with the laws of mechanics, by introducing major changes to mechanics close to the speed of light. This later became known as Einstein's Special theory of relativity.

In some of the articles I found online, the only particles referred to are photons. Other sources stated that light is an electromagnetic wave. Be careful though. If you consider the double-slit experiment, it's a toss-up on whether and when light is a particle or a wave or a charged particle is a particle or a wave. It can get pretty messy. Here's a great animation from YouTube explaining the experiment.

From the wikipedia again, here's a definition of electromagnetic radiation:

...a time-varying electric field generates a magnetic field and vice versa. Therefore, as an oscillating electric field generates an oscillating magnetic field, the magnetic field in turn generates an oscillating electric field, and so on. These oscillating fields together form an electromagnetic wave.

For an interactive illustration of an electromagnetic wave, try Molecular Expressions. You may be prompted to download and install the Java Runtime Environment to view the animation. It's well worth the effort.

Journal entry dated 6 May 2007
Category: Whatis Aquarian, Food for thought