HOW GAS PUMPS KNOW WHEN TO TURN THEMSELVES OFF

It’s quite amazing how simple physics are used in everyday objects and techniques which we tend to take for granted. One of those objects, it the cleverly designed gas nozzle. 

Prolific science vlogger and author Steve Mould dedicated a series to learning the true skills of the gas nozzle. In his video, Mould cut a gas nozzle in half to explore the well thought out design, and as it turns out it turns itself off automatically when the car’s gas tank is full.  

The whole process of the gas pump and nozzle process relies on a series of Venturi tubes, levers, and ball bearings. These equalise the internal pressure within the nozzle when the tank is full and prevent overflow. The entire behaviour is based on simple fluid dynamics and the exchange of pressure which causes the gas to flow as well as stop. 

One could explain the whole physics process of it, but it’s probably safer if you just watch the video with Mould’s engaging visual examples of the concepts involved.

“Gas or petrol pump nozzles turn off automatically when your tank is full. The way it works is really clever and uses the venturi effect.”