1. Aim: How do we recognize various wave behaviors?
DO NOW:
1. Which wave phenomena is exemplified by this picture?
2. As the wave propagates, explain what happens to the…
speed of the wave
the wavelength of the wave
the frequency of the wave
- the amplitude of the wave

2. Polarization When a wave vibrates only in one plane
up-down
left-right
ONLY transverse waves can be polarized

3. Polarization of Light

4. Law of Reflection How to draw the diagram
The Law of Reflection states
Angle of incidence is equal to the angle of reflection
Normal Line: A reference line always drawn perpendicular to the surface USE A PROTRACTOR!!!!
Angle of incidence ϴi: angle made between the incident ray and the normal line
Angle of Reflection ϴr: angle made between the reflected ray and the normal line
Reflected Ray: The light ray on the way AWAY FROM the surface
Incidence Ray: The light ray on the way INTO the surface ϴi ϴr

5. Reflection from an irregular surface results in scattered, or
Diffuse Reflection
Reflection from an irregular
surface results in scattered, or
“diffuse” reflection.

6. Reflection of Light The bouncing of a wave off of a surface .
Regular reflection
Bouncing off of a Smooth surface
Mirrors, ponds
You can see an image of the object
Diffuse Reflection
Bouncing off of a Rough surface
The road, leaves, furniture, cloths
You can see light, but no image

7. Reflection of sound The bouncing of a wave off of a surface.
Regular reflection
Bouncing off of a Smooth surface
ECHOs
If the speed of sound in water is 1.5Km/s and the signal takes 0.8 seconds to come back to the boat, HOW DEEP IS THE WATER?

8. Reflection Ray Diagram
Object Distance
Image Distance
Object
Image
Appears where the virtual rays cross
Incident Rays
Incident Angle
Eye sees two diverging rays and traces them back
Reflected Ray
Reflected Angle
Normal Line
Law of Reflection in a PLANE mirror:
Object distance (do) is equal to image distance (di)
Mirror

9. Summary What does it mean for a wave to be polarized?
What is the “Law of Reflection”?
Describe diffuse reflection

10. Reflection Lab Goals: To draw a 2-ray diagram of a single pin image
Use this diagram to compare the incident angles to the reflected angle
- Use percent difference to determine if the object distance is the same as the image distance
Use this diagram to compare image distance to object distance
Use percent difference to determine if the object distance is the same as the image distance

11. 1. Draw a line down the middle of the page, perpendicular to the edge of the page

12. 2. Prop the mirror up against the book with the BACK surface of the mirror on your mirror line. Make sure the cardboard is under the paper

13. 3. Stick the pin in the middle of the page

14. 4. Look in the mirror from the angle and locate the image of the pin in the mirror

15. 5. Line up the edge of the ruler such that if extended into the mirror, it would run straight into the pin. Trace that line

16. 6. Repeat step 5 from the other side

17. 7. Extend the reflected rays back to the mirror 8
7. Extend the reflected rays back to the mirror 8. Draw a line connecting the object to the place on the mirror where the reflected rays hit

18. 9. Trace the VIRTUAL rays back behind the mirror
9. Trace the VIRTUAL rays back behind the mirror. The image appears where the rays meet

19. 10. Use a protractor to construct the normal perpendicular to the mirror at the point where the rays hit the mirror Measure both incident and reflected rays and compare them using a percent difference

20. 12. Label and measure the object distance and the image distance
12. Label and measure the object distance and the image distance. Using percent difference, compare these two numbers

21. Results
Use this diagram to compare the incident angles to the reflected angle
Use this diagram to compare image distance to object distance