Colorado State University

Sometimes called a wormhole or infinity box, this experiment creates an illusion of an endless tunnel of lights going off into the distance forever!

What’s Going On

There crux of this experiment is the partially reflective mirror (sometimes called a two-way mirror). These mirrors reflect some light (like a normal mirror), but also let some light through (like a window). The holiday lights are in between the two mirrors, at least one of which is partially reflective. The light bounces back and forth many times between the mirrors, but each time some of the light get outs and that’s what you see!

Materials

• 1 partially reflective mirror (we used this acrylic see-through mirror)
• 1 regular mirror (or a second partially reflective mirror)*
• 1 string of holiday lights (we used battery powered to make it portable)
• 1 embroidery hoop or a set of welding/braising goggles
• hot glue
• utility knife/glass cutter, a straight edge, and sand paper (optional)

*Using two partially reflective mirror means you can see the illusion from both the front and back sides of your goggles/mirror, since light will come out of both mirrors. However, if you replace one of the mirrors with a standard mirror (reflective side in), the illusion will be brighter and will appear to go deeper into the distance.

How to Build

We used the utility knife to and straight edge to score the acrylic mirrors, and the snapped them to the proper size. We then used the sand paper to smooth out the edges. Once you have the mirrors properly sized, glue a partially reflective mirror to the embroidery hoop or goggles. We made sure to have the silvered side facing inwards so it would not get scratched. Glue in the holiday lights inside around the edges. You might need to cut a small notch to get run the cord out. Finally glue in your second mirror; if you’re using a standard mirror, make sure the reflective side is pointed inwards. Turn on the holiday lights and enjoy your new experiment!