Falling beer bubbles...

[w=f[z]]

Hi everyone,

Here is one more to go along with the balloon and 1/4 mile questions while I'm at it.

 

 

Let's say you are standing near a cliff. You crack open a bottle of beer and immediately let go of the bottle over the cliff (imagine it remains upright throughout the fall and no beer spills during the fall).

 

(I know, I know... what a waste of beer - even in the interest of science....)

 

So the question is this;

which way do the bubbles move relative to the bottle during the fall?

 

Cheers (literally )

w=f[z]

 

P.S. Again, newbie here. So sorry if this has already been discussed.

[insane_alien]

i imagine, they would have a relative velocity of zero. as long as it is in freefall, as air resistance becomes significant tey will rise to the top

[swansont]

Generally up, since the motion is constrained, i.e. they can't move down, and you have a larger volume trying to fit in the container.. You'd get bubbles and beer spewing out the top, since the bubbles will push the beer instead of just passing through. That moves the center of mass up, so that's the general direction of motion of the bubbles.

[richard]

Wot insane alien said. The beer and gas will fall at the same rate.

[YT2095]

it Should behave in exactly the same way that Coke does on the space shuttle or the ISS.

[swansont]

Wot insane alien said. The beer and gas will fall at the same rate.

 

But the volume is expanding, and not isotropically.