166 EXPERIMENTAL GENERAL SCIENCE 



22. Why is bluing added to water in which clothes are rinsed in 

 laundering? 



23. What color of paper is best for wrapping up white goods to give 

 them a white appearance? 



24. Should a girl with red hair wear blue? Why? 



25. Hold a piece of green glass before one eye, and a piece of red glass 

 before the other, and look at some white object for a few minutes. Then 

 look through one of the glasses, first with one eye and then the other. 

 Explain the difference in the brightness of the color noted. 



26. Cut various shapes out of black paper. Lay them on a green or 

 red surface, such as a book cover, and cover them with a thin sheet of 

 white tissue paper. Hold in the light and explain the apparent color 

 of the objects. 



27. Why does the photographer find it necessary to use a red or orange 

 light in his dark room? 



28. Examine plants grown in the dark, or the grass over which a board 

 has lain for a few days. What effect has light on the color of plants? 



29. Why does a blue dress look black in red light? 



30. In photographing colored objects, a color-screen of light yellow 

 glass is often used. How does this assist the reds and yellows to register 

 properly? 



