Science Questions

Why don't we choke when we drink through a straw?

If you’re drinking a milkshake or any other drink with a straw, when you finish, you can use your lungs to suck up all the last bits through the straw. It doesn’t matter how hard you suck, why don’t we choke? Stephen, New Jersey

Kat -   Okay, I have done extensive research into this question myself last night with some rum-based cocktails.  So, this is….

Chris Smith:  It would have to be rum or can it be anything?

Kat -   Anything would work, yes, but I’d like Margaritas.  But, you can’t really drink them through a straw and I will be publishing my results in the journal of Inebreology very soon.  But, basically, the reason is, is that when you’re drinking a drink that’s a full drink, you create a vacuum in your mouth and that’s basically what forces the liquid up the straw.  You’re not really kind of sucking it up.  You’re actually dropping the pressure in your mouth and that causes the liquid to go up the straw.  What happens when you get right down to the bottom of your drink is that there’s very little liquid there.  So, if you start there’s not really a lot of liquid that’s gonna go up into your lungs even it was to get there.  The other thing is that fluid is a lot heavier than air and when you actually do the motion of sucking something up from the bottom of your cocktail glass or your milkshake, you kind of form a barrier at the back of your throat with like soft palate or things like that.  So, the dregs of fluid come up the straw, they get into your mouth, they kind of go 'phleh' into your mouth while the air gets..

Chris Smith:  How it go again?

Kat -   'Phleh'

Chris Smith:  Just checking.

Kat -   That’s the scientific term I think you’ll find.  It sort of goes 'phleh' into your mouth.  They don’t really make it to the back of your throat to go down your lungs, but if you are a clumsy or a very enthusiastic drinker.  It is possible to inhale fluid into your lungs up a straw, but most of us have kind of learned how to drink so we don’t do it.

June 2009