Sources of Light
Luminous objects produce light. (i.e. the sun, firefly, burning match, lightbulb)
Click on the website below to check out some luminous objects:
Illuminated objects reflect light. These objects do NOT produce their own light. (i.e. the moon)
Light and Materials
Objects that let all of the light pass through (i.e. see through).
Objects that let only some of the light through.
Objects that do not let any light through.
Here are descriptions for the terms in this diagram:
- The ray of light which strikes the surface is called the incident ray.
- The ray of light which leaves the surface is called the reflected ray.
- A line perpendicular to the surface is imagined at the point of reflection. This line is called a normal. In this context the word normal means perpendicular. In the above diagram the normal is colored blue.
- The angle between the incident ray and the normal is called the angle of incidence, or the incident angle.
- The angle between the reflected ray and the normal is called the angle of reflection, or the reflected angle.
Notice that the angle of incidence is equal to the angle of reflection. This is called the Law of Reflection. Reflection needs a hard, smooth surface in order to bounce off. The light rays will scatter off of a soft, rough surface and therefore there will be no reflection.
Look at the image below. Why are the mountains reflecting off the smooth water surface and not the wavy water surface?
Refraction is the bending of light. As light passes from one transparent medium to another, the speed of light changes, and it bends.
Below I have included many examples of refraction:
There is no water on the road so why does it look like there is?