Ch. 19: Reflection, Absorption, and Refraction of Light

Vocabulary:

reflection, absorption, transmit, refraction

When Light Strikes an Object

• Light travels in a straight line.

• It will continue moving in a straight line, until it hit something.

• Depending on what it hits, light may behave in very different ways.

Reflection

• When light bounces off a surface, it is called reflection.

• When light is reflected it travels in a straight line away from the reflecting surface.

• Example of Reflection:

http://www.openschool.bc.ca/elementary/science4/html/bouncingLight.htm

Absorption

• Any time light hits a surface, some of it is absorbed, or taken in.

• When light is absorbed into a surface it is transformed from light energy, into heat energy.

• That is why on a sunny day it is cooler to wear a white t-shirt, than a black t-shirt; dark surfaces absorb more light than lighter surfaces.

Refraction

• Some materials transmit light, or allow light to pass through them.

• These transparent materials cause light to bend as it is passing through the surface.

• When the light bends, it makes things look like they do not match up.

Questions About Chapter 19

1. Which color absorbs the most light?2. When light bounces off a surface, what is it

called?3. Describe what happens to light when it

passes through glass or water.4. What happens to a material when it absorbs

light?5. On a summer day, why is blacktop so much

hotter than the dirt next to it?