You don't need to be a physicist to try out this technique: use photography to freeze light.

Freezing light

For this assignment, imagine you are a painter as well as a photographer: using a flashlight as your brush and the frame as your canvas, you can paint fantastic shapes with light. You will also need a tripod, or some other stable surface to hold your camera steady for a long exposure. Start by setting your camera to Tv mode and choosing the lowest ISO possible. Then, choose a shutter speed that's long enough to freeze the light rays like a drawing (about 15-30 seconds). Now, set the timer and go!

Tip#1: Use Manual mode for best results

This is a fun assignment, but not a fast one: it takes practice, so you'll need to be patient. Experiment with different exposure variations in Manual (M) mode to control the brightness of the background and overall environment.

Tip#2: Use flash

Find the flash synchronization setting in your camera and set it to the 2nd curtain. This will make the flash strobe at the end of your long exposure, and fix your (or your model's) position inside the frame after you've finished painting with flashlight.

Tip #3: Experiment with light

There are lots of ways to get creative with this assignment: try using different colored lights or filters, or turning your "paintbrushes" on and off to break up the lines. And get some help from your friends – it could turn into a quite an artistic performance!