moas infinity1.png
Images of images can repeat forever and ever and ever

Light: Demonstrating multiple reflections

Sunshine State Standards: SC.B.1.2 SC.B.2.

Materials:

  • Square pieces of plex-mirror, one with a hole cut in the center
  • Stand with a peg in the middle

To Know:
Multiple mirrors can be used to reflect an image multiple times. By using two mirrors parallel to each other, the image can be reflected back and forth many times. If a hole is cut in the center of one of the mirrors, you can see the reflection going to infinity

To Do and Notice:

  • Stand the mirrors so that their reflecting surfaces face each other and are parallel to each other. The mirrors can be anywhere from a few inches to a foot apart.
  • With the reflecting surfaces facing each other, look through the hole into the space between the mirrors
  • Try placing the peg between the mirrors.
  • If you place the peg between the mirrors, notice that there is a repetitious pattern in the orientation and spacing of the images. Objects with contrasting colors on the front and back (such as red and white) show this well.
  • Successive images will alternate from front view to back view.

moas infinity2.png

  • If the original object is closer to one mirror than to the other, the distance between successive images will alternate from close together to far apart – making the images seem to be grouped in pairs, with a front side always facing a front side, or a back side always facing a back side

What’s Happening?

  • In the light-ray diagram, the solid lines show the actual path of the light rays; the dashed lines show the path of the light rays projected by your brain. You see images where the dashed lines come together.

moas infinity3.png

  • This light-ray diagram shows the rays that come from the front of an object and those that come from the back. After the first reflection, you see one image in each mirror where the dashed lines come together (1). After the second reflection, you see a second image in each mirror (2), and so on.
  • As you look at the images formed in one of the mirrors on the diagram, notice that there is an alternation of front and back views, that the images appear to be grouped in pairs, and that a front side is always facing a front side and a back side is always facing a back side. This corresponds to what you actually observe in the mirrors.

Learn more…

Developed by the GE Volunteers in partnership with the Museum of Arts and Sciences (MOAS) – Daytona Beach, FL