THE REFLECTION OF LIGHT 29 



6. If you were choosing a house in which to live, 

 what would you notice especially? 



7. Give two proofs that light travels in straight 

 lines. 



8. Why is the image in the pin-hole camera upside 

 down ? 



15. The Reflection of Light. 



Light travels in straight lines until it strikes against 

 something. Then it is turned back, and, although it still 

 travels in straight lines, the direction of the light has 

 been changed. This turning, or bending, of light is called 

 reflection. When the object which causes the reflec- 

 tion is smooth and shiny we seem to see the light in the 

 object. If you look at the reflection of any object in a 

 mirror, it seems to be back of the mirror. This is called 

 regular reflection, because what we see appears just like 

 the object. The appearance of an object in a mirror is 

 called an image.' Can you imagine why it is called an 

 image? 



Experiment 17. Reflection from Mirrors. 



Apparatus: Mirror at least 2"x4", block of wood 

 2"x2"x4", two rubber bands, foot rule, pin. 



a. Turn the mirror toward the sun but tip it down- 

 ward so that the reflected light is on the wall about as 

 high as your head. Now turn the mirror about 45 de- 

 grees to the right. Through how many degrees does the 

 spot of light move? Repeat, turning the mirror to the 

 left. What result do you obtain? In turning the mirror 

 from the right position to the left position you moved it 



