1. Created for CVCA Physics By Dick Heckathorn 1 June 2K + 5
Ray Box Investigations For Reflection - Refraction and Total Internal Reflection
Created for CVCA Physics By
Dick Heckathorn
1 June 2K + 5

2. #1 #2
30o
30o
60o
60o #3
Rays 1-2-3

3. Conclusion The angles are measured from the normal.
The angle of incidence equals the angle of reflection.

4. Reflection r N i

5. Conclusion The angles are measured from the normal.
The angle of incidence equals the angle of refraction.
The incident ray, reflected ray and the normal all lie in the same plane.

6. Repeat for other three occurrences
Reflect ray of light from mirror as shown.
Insert a pin (1) on reflected light ray.
Locate reflection surface of mirror on line.
Mark and draw the light rays on paper
Draw a line across center of paper
Insert pin into cardboard as shown.
Extend reflected rays behind mirror
Remove mirror
The image is located where the rays cross.
Draw a line from object to image
How is this line oriented relative to mirror line?
Repeat for rays 3 and 4.
How does length of red and purple line compare?
Insert pin (2) on ray and draw it.
Draw normal lines and compare angle ‘i’ and ‘r’
Repeat for other three occurrences
Reflect a 2nd ray from mirror as shown
Image
Mirror i r
Pin 4 3 2 1

7. Conclusion
The image is always as far behind the reflecting surface (mirror) as the object is in front.
The line connecting the image and object is perpendicular to the reflecting surface (mirror).

8. Note angle ‘i’ equals angle ‘r’ Draw line from object to mirror
Locate object.
Light travels this path from object to pin
Note angle ‘i’ equals angle ‘r’
Draw line from object to mirror
Why know where the image is?
Repeat for eye 2, 3, and 4
Draw line representing mirror.
Connect eye (1) and image
Then draw line from mirror to eye 1
Locate eye (1)
Locate image
Image
Mirror surface r i
Object
Pin 3 1 2 4

9. Conclusion
Locating the image allows one to predict the path light will travel from the object to some location.

10. I1,2 I1
Mirror (1) I2
Object
Mirror (2)

11. Mirror (1)
Mirror (2)
I1,2 I2 I1
Object

12. Periscope I1
Object
I1,2

13. Pepper Ghost
Bottle of Water
90o
Plexiglas
Candle

14. Peppers Ghost

15. T29-1B

16. T29-1B

17. T29-1B

18. All rays parallel to P.A. reflect back through ‘F’
#19 V
P.A. F f
All rays parallel to P.A. reflect back through ‘F’

19. Parabolic Mirror
#20

20. Not all rays parallel to P.A. reflect back through ‘F’
Circular Mirror
P.A.
Not all rays parallel to P.A. reflect back through ‘F’

21. Circular Mirror
P.A.

22. Go to curved mirror PowerPoint.
Click

23. N #4 i r
Measure angle i and angle r.
Both = 0o

24. N #5
300 i r
19.50
Calculate
Measure angle i and angle r.

25. Measure angle i and angle r.#6
600 i r
35.30
Calculate
Measure angle i and angle r.

26. 1.50 is called the index of refraction (nP) of the plastic.
Using
for both angles,
what value did you get?
It should be near 1.50
1.50 is called the index of refraction (nP) of the plastic.

27. Test your drawing with a light ray. Calculate the angle of refraction.
Quiz N
750
40.10
Test your drawing with a light ray.
Calculate the angle of refraction.
Draw the refracted ray.
Draw an incident ray of 75o.

28. N #7

29. N
Use light ray to check.
Draw the refracted ray
Bent away/toward normal?
Calculate angle of refraction
30.90
30.90
200 #8

30. It tells us which way the refracted ray bends.
n1 sin θ1 = n2 sin θ2
It tells us which way the refracted ray bends.
Does it all!!!
What does it do?
How?
The bigger ‘n’ has the smaller ‘sin θ’ and thus the smaller ‘θ’ (angle).

31. Use light ray to check.
Calculate angle of refraction
Draw the refracted ray
Bent away/toward normal? N
74.60
74.60
400 #9

32. N
Calculate angle of refraction
Now what do we do?
Bent away/toward normal?
Use light ray to check.
Tilt!!
600
600
#10

33. N
What happens here?
750
#11
750

34. N

35. Demonstrations
T.I.R. Plastic
T.I.R. Water
T.I.R. Glass Tube
Ball in/out of Water
Mugs

36. Demo – Aquarium Balls
Aquarium Balls
Air
Water

37. Calculate angle of refraction Which way is ray bent?
300
#12
Calculate angle of refraction
Which way is ray bent?
Draw the refracted ray.
n=1.50
19.50
Draw the refracted ray.
Check with ray box.
Calculate angle of refraction
Which way is ray bent?
300

38. Calculate angle of refraction
#13
600
600 00
Calculate angle of refraction
Calculate angle of refraction
n=1.50

39. Calculate angle of refraction Calculate angle of refraction
18.20
11.80
280
17.80
#15
11.80
18.20
280
17.80
#14
n=1.50
Calculate angle of refraction
Calculate angle of refraction
Calculate angle of refraction
Calculate angle of refraction

40. #18

41. That’s All Folks!!
No 16-17