For the topic of light we will explore the unique characteristics of light that make it fascinating.
- Light is an electromagnetic wave, meaning it does not require a medium through which to travel. Light is said to be a transverse wave (particles vibrate perpendicular to the direction in which the wave is traveling.) It is kind of hard to describe light using this definition of transverse waves, however, because light does not use vibrating particles through which to travel. Because electromagnetic waves consist of electric fields and magnetic fields that travel perpendicular to one another all electromagnetic waves are considered transverse.
- Light is unique in the aspect that it behaves as a wave and as a particle. Light is produced as a photon (light particle.) Photons are produced as electrons release energy. Electrons release energy when the move back to original energy levels within an atom. Light also exhibits many of the same properties as waves, as well. Reflected light is what our eyes observe when we look in a mirror. Refraction is responsible for a prism breaking white light into all its component colors. (see below.) The famous Double Slit experiment by Thomas Young is caused by interference and shows the wave-particle duality of light. Click on the link to read about the experiment. Double-Slit Experiment
- The visible light we observe is part of a continuum of electromagnetic waves. As human beings we are capable of observing this very narrow range directly. This continuum is known as the electromagnetic spectrum. See below for specific wavelengths.
- Light interacts in 3 distinct ways when it come into contact with matter. It is either reflected, transmitted (allowed to pass through), or absorbed by the matter. How the matter effects the traveling light depends on what type of matter it is. Transparent matter allows light to pass through it easily. Translucent matter transmits the light, but some of the light is scattered in different directions as it passes through. Matter that is opaque does not transmit any light.
The following PDF files can be downloaded
Notes Chapter 22 Section 1
Notes Chapter 22 Section 2 Part A
Notes Chapter 22 Section 2 Part B
Notes Chapter 22 Section 3
Notes Chapter 22 Section 4