6. The critical angle for water is 48-1/2 degrees. Show by a diagram how much of the sky can be seen by a diver who looks upward through the water.
7. How is near-sightedness caused? How is it corrected? Illustrate by a diagram.
8. How is the eye accommodated (focused) as an object gradually approaches it?
9. Explain why a simple microscope assists in looking at the parts of a flower or insect.
10. Why do people who have good eyesight when young require glasses as they grow old?
(7) Color and Spectra
Guglielmo Marconi
"Copyright by Underwood & Underwood, N. Y."
Guglielmo Marconi (Italy). Inventor of wireless telegraphy.
Alexander Graham Bell
"Copyright by Underwood & Underwood, N. Y."
Alexander Graham Bell, Washington, D. C. Inventor of the telephone.