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Properties of Light
Light Contents
Students should be able to:
- explain reflection, bending (refraction), and transmission of light.
Main Idea
When light hits a surface, the light can be reflected, refracted, transmitted or absorbed.
Reflection of Light
Light travels in straight lines called rays. When light bounces off of an object or a surface, it reflects. Light rays reflect from a surface according to the law of reflection: they always reflect at the same angle that they hit the surface.
Take a look at the Flash mini-movie below. Use your mouse to drag the flashlight from side to side. Watch what happens to the light rays when they hit the mirror. Do they reflect at the same angle?
The ray from the flashlight hits the shiny surface and reflects off it at the same angle. Your parents are able to see behind them when they are driving their car because of the law of reflection. They can see cars that are coming up behind because the light reflecting off of the car hits their rearview mirror at angle and then bounces to their eyes.
Rearview mirrors work because of the law of reflection.
Refraction of Light
When light rays enter a new medium at angle, it refracts, or bends. This happens because the speed that the light is traveling changes making the light change direction. You probably have seen refraction take place when you've been swimming. Objects on the bottom of the pool look different because light reflected off them changes direction when it leaves the water and begins traveling through air.
In science class you may have had the opportunity to shine light through something called a refraction block. The block is made of acrylic, which is similar to glass, and when light strikes the surface of the block at angle, it bends. The Flash mini-movie below shows this in action. Drag the flashlight from side to side and watch how the light bends when passes through at angle.
Notice that as the light leaves the refraction block, it bends again and travels at the same angle it was going before entering the refraction block. We see refraction in the real world all the time. Check out the examples below.
Drag the flashlight from side to side to observe refraction of light.
Refraction in the Real World
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- Constitution Webquest
- Slavery in America
- Waves of Immigration
- Declaration of Independence