हवा को देखा है कभी ? नहीं! तो अब देख लो जेसे भूत - How To See Invisible Air

This is a demonstration of the Schlieren effect. This setup allows you to see changes in air density. 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.

Видео हवा को देखा है कभी ? नहीं! तो अब देख लो जेसे भूत - How To See Invisible Air канала MR. INDIAN HACKER