# Can I blow soap bubbles (of air) inside a vacuum chamber?

When I blow soap bubbles from a liquid dish soap mixed with distilled water at atmospheric pressure at ground level both internal and external air pressure nullify and the tension of the bubbles holds, can soap bubbles be formed inside a vacuum chamber with all air pumped out?

• Not an answer so much, but if there's gravity in this vacuum the soap bubble would fall like a stone. No gravity, I don't see why not. The bubble creates a slight pressure on the gas inside. Vacuum outside, small atmospheric pressure inside - which is matched by the pressure from the bubble. Similar to this question. physics.stackexchange.com/questions/127695/… I'd guess it's harder to make a bubble in those conditions, but if one was made, I think it would be stable. – userLTK Mar 24 '15 at 5:13
• Liquid water cannot exist as a stable equilibrium below 611.2 Pa. It will either be a solid or a gas. You might be able to get it to work using a different liquid. – DanielLC Mar 24 '15 at 6:59
• @DanielLC I agree, alright a "bubble gum" since water readily boils in vacuum of space. – user6760 Mar 24 '15 at 7:06
• Google "Bubbles in Vacuum" Lots of hits. For example this: youtube.com/watch?v=6DtzCVvR-Co – mmesser314 Mar 24 '15 at 13:25
• @mmesser314 very beautiful the silicon is bubbling as air is being drawn away. However as air is still presence when bubbling effects took place and no bubble form and trap when in total vacuum, I guess answer to my question is no what do you think? – user6760 Mar 25 '15 at 1:03

See, the internal pressure of a bubble exceeds the external pressure by $\dfrac{4S}{R}$ ; $S =$ surface tension,$R =$ radius. So, additional force must be imparted so as to keep the bubble in equilibrium.

So, if you want your bubble to exist in the chamber, there must be some mechanism to nullify the outward pressure of the bubble; otherwise it'll burst.

But as said by @Peter Shor, if you, by some means, could decrease the internal pressure of the bubble to such an extent that it becomes equal to surface tension factor, then the bubble will exist i.e. $$P_{int} \approx \dfrac{4S}{R}$$.

• There's surface tension: the same thing that keeps bubbles in equilibrium at atmospheric pressure (the pressure on the inside of a bubble is the same as the outside. So if you have very low internal pressure inside the bubble, and vacuum outside the bubble, I don't see why this shouldn't work. – Peter Shor Mar 24 '15 at 11:02
• @Peter Shor: Sir, in defence of my answer, I would assert that in absence of any outer atmospheric pressure, the bubble'll burst. Because, it is the surface tension plus outer atmospheric downward pressure that equalize the outward pressure from inside of the bubble. But, I apologize if there is still any wrong; anyone can modify the ans as I've posted it as "community wiki". After all, To err is human:) – user36790 Mar 24 '15 at 11:50
• But, sir, I can't consent with your statement that the air pressure inside & outside is same; if that was so, the bubble would collapse under surface tension. – user36790 Mar 24 '15 at 12:11
• You're right: the air pressure inside the bubble is larger than that outside. But couldn't a bubble exist in vacuum if the inner pressure was very low? – Peter Shor Mar 24 '15 at 12:37
• @user 6760: I don't know why you accepted it & why you undid it later! I've no problem in that; it depends on you. But I would be rather happy if you wrote what dearth of info let you to unaccept it after accepting so that I may help or may other. – user36790 Mar 24 '15 at 15:30

You would have quite a problem to keep your water liquid. Normally, the water will evaporate when pumping. So you should go to low temperatures, but it freezes there. I thin you should thing about some other material to make bubbles in vacuum.

• like maybe a balloon – Skaperen Mar 24 '15 at 9:29
• @jaromax very true it is my oversight, suppose we allow infrared radiation (heat) into the vacuum chamber so that the materials used can be kept constant at room temperature would the experiment work? if you agree with me I will include this condition into my question, thanks a lot. – user6760 Mar 25 '15 at 2:33
• @user6760 - still your water will turn into vapor. Do you remember that water boils at lower temperature in hills? It is very high hill - the vacuum. – jaromrax Mar 25 '15 at 11:54
• @jaromrax therefore crudely speaking the water molecules had very high energy and are jiggling around rapidly in a familiar fashion a.k.a "Brownian motion" however since there are so many water molecules crowd together leaving little room for movement hence they are able to exist as liquid at room temperature. I was thinking maybe removing some energy off these water molecules but as you've pointed out there is nothing to hold them together. Should I apply really strong magnetic field to trap them in a tiny confined space instead? actually I think the answer to my question is no. – user6760 Mar 25 '15 at 13:18
• @user6760 - look at P-T graph astro.uwo.ca/~jlandstr/planets/webfigs/matter/images/h2o.jpg. At some pressure, you dont have anymore the liquid phase (of water). – jaromrax Mar 26 '15 at 11:24

For the question, can a soap bubble exist in a vacuum? Your answer places certain assumptions on the soap bubble.

• Asump 1: There is pressure inside the bubble.

• Asump 2: There is no gravity.

• Asump 3: The structure of the bubble has the strength to exert force against the pressure inside the bubble.

1 A total vacuum exerts the same pressure inside the bubble as outside.

2 Gravity is never absent. It can only be overcome by weak and strong nuclear forces or electromagnetic forces.

3 The structure of the bubble is fixed and will have equal Pressure inside and outside the bubble in a total vacuum.

I think the better question is what shape will a bubble assume in a vacuum.

The equal Pressure within and without the bubble will create a sphere when combined with the repelling dielectric forces of soapy water which will stretch the bubble to it's maximum ability to hold its form. No other shape can be expected other than a sphere in this scenario.

• A soap bubble does not have equal pressure within and without. The pressure inside the bubble is slightly greater than the pressure outside. The slight pressure difference is balanced by the surface tension in the liquid film. The surface tension wants to collapse the bubble into a spherical liquid droplet. – Solomon Slow Jan 25 '16 at 21:57
• +igsel. The problem specifically states the bubble is formed in a vacuum. Ergo, no increased P will be found inside compared to outside. Weak molecular forces are the only repellant force acting on the chemicals making up the structure of the bubble. – Rrrick1 Jan 27 '16 at 0:43
• The bubble would have to be blown, so wouldn't there be increased pressure inside? – Richardbernstein Mar 8 '16 at 3:23

Unfortunately, you can not make a bubble with water and soap in a high vacuum.

as you can see in this phase diagram of pure water, if the pressure is lower than 611.657 Pa, liquid water will not exist no matter what the temperature is. Maybe you should try some other material, but not H2O.

• That's pure water. Does a dissolved detergent change the phase diagram? – Richardbernstein Mar 8 '16 at 3:21