What are the properties of light?

enotechris | College Teacher | (Level 2) Senior Educator

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The debate about the properties of light date back to the time of Isaac Newton (1642-1727) who first undertook to comprehend its properties through experimentation.  His belief was that light was composed of particles, and, being Newton, his view was accepted unquestionably by most of the scientific community. However, his contemporary, Francesco Grimaldi (1618-1663) performed an experiment where he noted for the first time the phenomena of diffraction, or the light bending around an obstacle, which would suggest light was a propagating wave.  Eventually, the wave theory became widely accepted, but with the advent of quantum mechanics, light again appeared to have particle properties.  Scaling down our analogies to subatomic scale to understand the phenomena discovered in that realm doesn't always work -- although difficult for us to comprehend at our human-sized scale of existence, light is considered to be both wave and particle, electromagnetic energy moving at an unvarying speed.

Asimov's Biographical Encyclopedia of Science and Technology, I. Asimov, pg. 100, 1964.

ladyvols1 | High School Teacher | (Level 3) Senior Educator

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As we learned in Physical Science, light has several different properties.  When a light wave is traveling in a straight line and comes in contact with some substance, or object the wave is reflected, refracted, absorbed, or transmitted.   Transmitted light is done so through a substance which we consider to be clear.  There is really no such thing as a substance which is totally clear, but glass is a good example of a substance which transmits light.  If a little light gets through and the waves are diffused the substance or object is said to be translucent.  An example of a translucent substance might be tinted windows in a car or a frosted window.  When light cannot go through a substance at all, the light waves are absorbed.  These objects are opaque.  Opaque objects might absorb all of the light or maybe only certain colors of the spectrum.  An iceberg looks blue because all the other colors of the spectrum are absorbed. Sometimes light that cannot be transmitted or defused is reflected in a different direction.  A mirror is an example of reflected light.

"Today, a somewhat simpler view of light as a wave phenomenon exists. Light is a form of radiation that needs no medium through which to travel. It consists of electric and magnetic fields that pulsate up and down as they travel through space."