Lasers, Smoke, and Ice

Smoke is really interesting. It’s a gas, so it ends up being very chaotic, especially when turbulent.

I was playing with lasers the other day and had the idea to make two-dimensional a plane of laser light and project it through smoke, effectively visually ‘cutting’ the laser smoke into a slice that I could see. So I attached a mirror with a 45 degree tilt to a computer fan, pointed a 5mW green laser at it, and spun it up.

After searching for the appropriate medium to create smoke (incense didn’t make enough to be very visual), my friends and I settled on using dry ice.

Here’s a picture with the lights on.

Pouring dry ice vapor through a plane of laser light.

And another with the lights out, this time of just a cube of dry ice held above the laser:

Dry ice cube held in a plane of laser light

The whole device was really easy to build (most computer case fans take 12 volts DC and you can get small mirrors at art supply stores). If you do end up making one of these devices, just please remember to be safe around lasers and dry ice. Never look a laser in the eye and never keep dry ice in an airtight container (it will explode).

And I’ll leave you with a video:

Oh, and thanks to Julia for helping and Jon for the photography.