COLOR 165 



8. Look at the sun through a piece of smoked glass, and explain the 

 change in color noted. 



9. What causes the sun to have a red hue'at sunset? 



10. Why does the sky appear blue? 



11. What color would the sky be if there were no dust in the air? 



12. Why do distant hills always look blue? 



13. What effect does the absence of dust have on twilight? 



14. When are the colors of sunset brightest, on a clear or on a partly 

 cloudy day? Why? 



15. What rays of light do plants absorb? 



16. Look at a blue object through a red glass. Explain the change 

 in color. 



17. What color would a red object appear in blue light? Why? 



18. Look at a white object through three combined sheets of glass, 

 red, green, and blue respectively. Explain the result. 



19. The mercury-vapor lamp, much used in factories, photograph 

 studios, and the like, give a bluish-green light with few or no red rays. 

 What would be the effect of putting a red glass chimney over the light? 



20. Why do people look pale in blue light? 



21. Why is it difficult to match colors by artificial light? 



