I’ve been playing around with a Schlieren setup lately and have a few videos to show for my effort. I plan on writing a series of posts explaining how Schlieren imaging works and describing how you can put a simple setup together for yourselves for a few hundred dollars. In the mean time, enjoy this montage of my Schlieren experiments.
In a nutshell, Schlieren imaging allows you to see very small changes in the index of refraction of any clear substance, such as air or water. Temperature gradients (as shown in the montage) as well as pressure waves can be seen quite clearly.
The first part of the clip shows me lighting a candle and then blowing it out. You can still see the hot air rising from the candle after it is blown out.
The second part of the clip has a butane lighter with the lever taped down. The initial flow you see is the butane, and once it is lit the hot air starts rising.
The third part of the clip shows the hot air rising from my hand. The effects are fairly subtle and I’m hoping to tweak the system to get a better look.
The final clip is of hot water getting injected by a syringe into a tank of cold water. You can very clearly see the currents as the warm and cold water mix.
All the clips actually show a double image because the light has to pass by each object twice.