The Venturi effect

Using a paper towel roll and an air compressor, the creator demonstrates how high-speed air creates suction by pulling surrounding air into the stream, a phenomenon known as the Venturi effect.

The process relies on the conservation of momentum. As high-speed air mixes with stationary air, the volume increases while velocity decreases, creating a low-pressure area that pulls in more air to fill the space.

The Venturi effect is widely utilized in gas furnaces to pre-mix fuel with air and in spray guns to atomize liquids by creating suction through high-speed airflow.

The creator demonstrates a DIY spray gun constructed with an air nozzle and a straw, explaining how negative pressure pulls liquid up into the high-speed air stream to break it into tiny droplets.