Exploratories

What Do You Really See

Purpose: To examine the images in a plane mirror

Materials: "Full-length mirror", Masking Tape, Ruler or Meter Stick

Preconceptions:

1. Where is the image that you see when looking in a mirror?

2. How big must a full length mirror be to see your whole body?

4. Do the same rules apply to the wall behind you?

5. Draw a diagram of yourself, the mirror, and the image of yourself as you visualize it. Draw the rays which come from your foot to your eye.

Procedure:

1. Stand 2 meters from a full length mirror so that you can see yourself in the mirror.

2. Have an assistant put a piece of masking tape on the mirror where you see your ankle in the mirror AND where you see the top of your head. Measure from the floor to the two pieces of tape. Leave the tape on the mirror.

3. Move to a distance of 1 meter from the mirror and slightly to one side so that the two pieces of tape on the mirror do not obstruct your view.

4. Repeat step 2.

6. Compare your measurements and draw conclusions. Include drawings which compare to your preconceptions.

The Wall Behind You

1. Stand two meters from the mirror and observe a large object (lamp, door, etc.) behind you which has both height and width.

2. Have assistant put tape on mirror where you see the top, bottom, and sides of the object you have chosen. Make measurements. Leave tape on mirror.

3. Move to a distance of 1 meter from the mirror and slightly to one side so that the tapes on the mirror will not obstruct your view.

4. Repeat step 2 for the same object.

5. Analyze your results and draw conclusions. Include drawings which show the object, mirror, image, rays from your eye to the edges of the image.

Double Mirror

1. Find a combination of mirrors such that one is fixed and one is hinged so that it can make any angle from 0 to 90 degrees with the other... such as is found in many bathrooms.

2. Start with the mirrors at 90 degrees. Look into the mirror and observe the number of images you see of yourself. Identify properties of each image and their location... include the concepts of right and left-handedness. Try combing your hair while looking at each image.

3. Begin slowly rotating the mirror and note any effects on each of the images.

4. Rotate mirror until you achieve a new number of complete images of yourself. Note the angle between the mirrors. Make same observations as in step 2.

5. Again continue to rotate until you again achieve a new number of complete images. Note the angle between the mirrors. Make same observations as in step 2.

6. Use your previous observations to PREDICT the next angle at which you would again achieve a new number of complete images and PREDICT the number of images.

Summary

Write down as many general rules and conclusions as a result of your measurements and observations.