valeyard89 t1_j9mlc74 wrote on February 23, 2023 at 1:27 AM

Reply to comment by -domi- in Eli5: how do pressurized spray cans work? Spray paint, cooking oils, hairspray etc by garlicknotter

if you blow across the top of a straw dipped in water, it creates low pressure in the top part of the straw, which draws up the liquid from below.

-domi- t1_j9mot82 wrote on February 23, 2023 at 1:52 AM

The venturi effect you're describing is not how spray cans work. It is how (a lot of) spray guns work for airbrishing and stuff. But typical aerosol cans are literally just a substance that's kept liquid by the pressure it's under, with a straw dipped in it leading to a nozzle you can open. That's why once a can gets somewhat empty, you can only get a decent amount of paint/oil/hairspray/etc out if you hold it upright.