1. Rotating Head Periscopes Why U-boat Captains Have To Spin In Circles These periscopes are resource material to support parts of STAO’s ScienceWorks Grade 10 Optics The following are excerpts from L4 The Laws of Reflection (Slides 21-35 of58) and L5 Putting Things Together (Slides 1-14 of54) Safety note; Extra tape should be placed at the corners to cushion some of the sharp edges on the plastic mirrors.

2. Periscopes Why U-boat Captains Have To Spin In Circles 1)Use the laws of reflection to show how the Eye/Brain sees the top and bottom of a candle in a periscope?

3. Periscopes Why U-boat Captains Have To Spin In Circles Roughly parallel rays from the top and bottom of the candle move towards the top mirror

4. Periscopes Why U-boat Captains Have To Spin In Circles Angle of Incidence = Angle of Reflection (  i =  r ) and the rays move towards the bottom mirror

5. Periscopes Why U-boat Captains Have To Spin In Circles Angle of Incidence = Angle of Reflection (  i =  r ) and the rays move towards the Eye/Brain mirror Note: This does not predict the Image’s location.

6. Periscopes Why U-boat Captains Have To Spin In Circles The candle’s image appears erect.

7. 2)Use the laws of reflection to show how the Eye/Brain sees the top and bottom of a candle if the top mirror is be rotated to face backwards? Periscopes Why U-boat Captains Have To Spin In Circles

8. Periscopes Why U-boat Captains Have To Spin In Circles Roughly parallel rays from the top and bottom of the candle move towards the top mirror

9. Periscopes Why U-boat Captains Have To Spin In Circles Angle of Incidence = Angle of Reflection (  i =  r ) and the rays move towards the bottom mirror

10. Periscopes Why U-boat Captains Have To Spin In Circles Angle of Incidence = Angle of Reflection (  i =  r ) and the rays move towards the Eye/Brain mirror Note: This does not predict the Image’s location.

11. Periscopes Why U-boat Captains Have To Spin In Circles The candle’s image appears inverted.

12. 3)Use the laws of reflection to show how the Eye/Brain sees the top and bottom of a candle if the top mirror is rotated to face sideways? Periscopes Why U-boat Captains Have To Spin In Circles

13. The candle appears to be sideways. Periscopes Why U-boat Captains Have To Spin In Circles

14. Periscopes Why U-boat Captains Have To Spin In Circles The man of science has learned to believe in justification, not by faith, but by verification. — Thomas Henry Huxley

15. Seeing Things Putting Things Together Periscopes, Hinged Mirrored & Kaleidoscopes

16. 1)Where exactly are the Images in a periscope AND how do light rays reach the Eye/Brain from the Object? Periscopes

17. Find the first image (Image 1) in the top mirror using equal perpendicular distances. You have to extend the mirror to locate the Image.

18. Images can act like Objects. Find the second image in the bottom mirror the same way. But this time use Image 1 as the new Object

19. The Eye/Brain sees the second image in the bottom mirror as usual. Rays of light appear to come straight from it.

20. Light rays cannot travel through the opaque bottom mirror. They must have come from the Object (Image 1) and reflected off the mirror.

21. The light rays cannot travel through the opaque top mirror. They must have come from the real Object and reflected off the top mirror.

22. Your Turn Attempt the Questions on L5 Putting Things Together Student Notes Periscopes

23. 2)Where exactly are the Images in a reversed periscope AND how do light rays reach the Eye/Brain?

24. Find the first image (Image 1) in the top mirror using equal perpendicular distances. You have to extend the mirror to locate the Image.

25. Images can act like Objects. Find the second image in the bottom mirror the same way. But this time use Image 1 as the new Object

26. The Eye/Brain sees the second image in the bottom mirror as usual. Rays of light appear to come straight from it.

27. Light rays cannot travel through the opaque bottom mirror. They must have come from the Object (Image 1) and reflected off the mirror.

28. The light rays cannot travel through the opaque top mirror. They must have come from the real Object and reflected off the top mirror.