1. Wave Interactions
Unit 12
Section 3

2. I. Reflection Sometimes a wave bounces back after hitting a barrier.
When the bouncing back of light, sound or heat takes place, it is called reflection.
An echo is a reflected sound wave.
When a wave hits a barrier and keeps moving through the barrier, the wave has been transmitted (sent through) through the barrier rather than reflecting back.

5. http://video. search. yahoo. com/video/play

6. II. Refraction
Refraction is the bending of a wave as the wave passes between two substances in which the speed of the wave differ.
i. This makes the object appear bent.
This happens because you are putting the
object in different media and the
wavelength changes in different media.
Light waves travels slower through liquids
than it does through gases (air) so the light
wave slows down once it hits the water.
This change in speed causes the object to
appear bent.

7. An example of refraction
Medium is air
As a result of the light waves hitting the spoon in the air and the water at an angle, the spoon appears bent. This is refraction.
Medium is water

9. http://video. search. yahoo. com/video/play

10. Quickie Quiz
____________ happens when a wave passes from one medium to another at an angle.
Diffraction
Refraction
Reflection
Interference

11. Quickie Quiz The bending of a wave around a barrier is called
Refraction
Diffraction
Reflection
Interference

12. Quickie Quiz
We can see the moon because of the ________________ of sunlight off it.
Refraction
Diffraction
Reflection
Interference

13. Quickie Quiz
A reflected sound wave is a called an __________________.

14. Quickie Quiz
Why does the spoon appear to bend in this picture?

15. Quickie Quiz
When a wave hits a surface and keeps going, rather than bouncing off of it, the wave has been
Reflected
Transmitted
Echoed
Diffracted