Exploratories

Images, Images, Images

Problem

How does reflected light travel to your eyes?

Materials

Two plane laboratory mirrors, supports for the mirrors, two single hole rubber stoppers, two identical pencils or two identical drinking straws

Procedure

Part A
Set one plane mirror upright on a sheet of paper as shown in illustration A. Place a pencil or straw--vertically supported in a rubber stopper--in front of the mirror. Locate the image of the object in the mirror. (See Illustration A) Place a second stopper behind the mirror
where you think the image of the first appears to be. (If you have located the image correctly, the image of the first pencil or straw and the second pencil or straw itself will remain "together" as you move your head from side to side.) Draw the path you think the light takes from the first object to your eye as you observe the image. Draw a dotted line to where the image appears or is seen by the observing eye.

Part B

Set up two mirrors on their edges and at right angles to each other (Illustration B). Place a vertically supported object between the mirrors. How many images do you see? Mark where the images seem to be located. Now draw the paths you think light takes from the object that enables you to see the images.

Summing Up

1. In procedure A, how did the distance from the first object to the mirror compare to the distance from the mirror to the image?

2. In procedure B, what happens to the number of images you can get if you decrease the angle between the two mirrors?