Ever wonder how a gas pump somehow knows when to stop before gasoline pours all over your car? There isn't a camera or computer inside the nozzle measuring your fuel level. The automatic shutoff is a clever mechanical system that uses airflow, suction, and the Venturi effect. A tiny sensing hole near the nozzle tip allows air to flow while you're filling. As gasoline rises and covers that hole, the change in pressure triggers the nozzle's shutoff mechanism.

In this episode, we break down the surprisingly simple engineering inside a gas nozzle, why the pump can sometimes click off before the tank is actually full, and why repeatedly “topping off” your tank isn't a great idea. It's a small piece of everyday engineering that most drivers use constantly without ever thinking about how it works.

Approx. Runtime: 45 minutes ...