Air density probably isn’t something you think about every day. Well, thanks to the Schlieren effect there’s now a reason to do just that.
After being discovered by German scientist August Toefler in 1864, the Schlieren effect has been most widely used in aeronautical engineering to visualize the flow of air around the body of airplanes.
This is how it works as described by the video’s creator, brusspup:
The point light source is aimed at the concave mirror. The concave mirror reflects to a focal point. There you use a sharp edged object to partially block the light which helps create a shadow effect that allows you to see air movement.
However, it’s also just extremely cool to look at. When different objects — like a dry blower, an ice pop or a can of pressurized air — are held and used in front of the camera, it creates a beautiful effect.