Making light visible in the air
Some cooking skills required
I wanted to make a picture on the theme "private", and experimented with light coming through a keyhole. I started by placing a fairly strong lamp on the other side of the hole. Unfortunately, the effect was not very dramatic since the light travelling through the hole was not visible in the air - this usually only happens if the air is dusty or foggy. I was considering opening the vacuum cleaner bag to fill the air with dust, but tried a cleaner method: Steam! I simply boiled a pot of water and put it under the keyhole. The light shining through the steam became visible and made for a much better shot.