1. Refraction
Science or Magic?

2. Agree or Disagree?
A swimming pool is always deeper than it appears

3. Agree or Disagree?
In order to see a rainbow, the Sun must be shining in one part of the sky while rain or clouds are in the opposite part of the sky

4. Agree or Disagree?
A periscope is an optical device that allows you to see around corners

5. Agree or Disagree?
When you see a mirage, you are really looking at an image of the sky

6. What is Refraction?
We know that light travels in straight lines through air
What happens when it travels from one material (medium) into another?
Try the ‘Explore with Light’ activity on Page 515

7. Light in an Aquarium
Use a flashlight and demonstrate refraction

8. How fast is the Speed of Light?
We use the speed of light in a vacuum (slightly more than it is in air), which is 3 x 108 m/s

9. What causes refraction?
Speed of light in water (2.26 x 108 m/s) is less than in air (3.0 x 108 m/s)
We’re the same – try running in water!
Like when right wheels of car go off road onto sandy shoulder – car pulls to right

10. Angle of refraction The angle between refracted light ray and normal
Angle between light and normal in air (above water) still called angle of incidence

11. Rules for Refraction
Incident ray, refracted ray and normal are in the same plane
Incident ray and refracted ray are on opposite sides of the boundary between media (eg. air and water)
Light bends toward normal when speed of light in second medium is less than first
Light bends away from normal when speed of light in second medium is greater than first

12. Side view of tank: rays in same plane
Air to water
Water to air

13. Rules for Refraction
Light bends toward normal from air to water since speed of light in water is less than in air

14. Homework
Pg. 519 #1 to 4