Viewing a single comment thread. View all comments

-domi- t1_j9kis6d wrote

One aspect that hasn't been covered by comments thus far is that the nozzle which you operate with your finger has a straw attached to it. That straw is dipped in the liquid content. That's why if you start running low on paint, oil, hairspray, etc, you have to keep the can upright in order to get the intended content out.

3

valeyard89 t1_j9mlc74 wrote

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.

1

-domi- t1_j9mot82 wrote

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.

1