We all have them in our photo albums: the photos taken with a flash straight into a window. The reflection of the harsh flash hovers over the heads of your friends because you forgot to take a step to the side and shoot a little bit diagonally into the window. If the window was a retroreflector, like a funflector safety reflector or a road sign, you would have got the flash bouncing back into your camera lens no matter where you were shooting from. Below and in our next post are some easy and fun ideas for a science project for schools or scout groups. These will help understand how retroreflectors work and why they can be so effective despite their small size.
Science Project with Safety Reflector & Laser Pointer
This video shows how a laser beam gets reflected right back to where it came from by a safety reflector.
Watch how it lights up the laser pointer and the hand holding it! (Please make sure the laser pointer is handled by an adult.)
The laser beam hits the safety reflector and get sent right back to the laser pointer. See how red the laser pointer and hand turns red!
That’s why road signs and safety reflectors look bright instead of bouncing the light from your car’s headlight into the trees and fields. When you drive in the dark, your headlights are your camera flash and your eyes are your lens. So, how does that work?
How does a retroreflector (safety reflector) work?
When light falls on a flat glossy or reflective surface like a mirror, it only goes back to where it came from if it falls straight into the mirror (the pink ray). If the light falls on a mirror at an angle (orange or blue ray), it will bounce out the opposite direction. A prismatic retroreflector catches the bounced light with a second mirror. Therefore, it bounces out in the same direction it came from no matter at what angle it comes in at. A cat’s eye reflector consist of small glass beads. It works like a prism to bend the light and reflect it back out in the same direction as it came from.
Funflector safety reflectors are made with a soft micro prism material by 3M Scotchlite. A close look reveals the prismatic structure of the plastic.
The funflector team 🙂
