Can an Ant Survive Walking on a Soap Bubble?

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An ant can theoretically walk on a soap bubble due to the pressure dynamics of its feet being lower than the bubble's surface tension. However, practical attempts show that the ant may become immobilized in the foam, as its body geometry disrupts the bubble's surface. In a recent experiment, an ant was placed on soap foam and quickly got stuck, eventually sinking into the layers and appearing to die shortly after. This outcome raises ethical concerns about using ants for such experiments. Overall, while the physics suggests it could work, the reality is more complicated and potentially harmful to the ant.
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Could a tiny sugar ant walk on a soap bubble? Would the bubble burst? Would the ant be able to locomote along the surface or would it get stuck?
 
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you can touch bubbles without them bursting, so I guess an ant could.
Find an ant, make a bubble, put the ant on it. It might even work :D
 
I'm guessing it would be pretty difficult, but an ant could walk across a soap bubble. As mike mentioned, you can make significant sustained contact with a bubble without it bursting. To the ant it may be more like swimming though.
 
I'm fairly certain that the pull of gravity would move the ant downward, and the traction it could achieve would not be sufficient to counter that pull. It would be like trying to swim up a waterfall.
 
As Lurch observes, it wouldn't get much traction if it could walk. It would be more like swimming. Whether the ant will be suspened on the surface, be drawn-in, or pop the film depends upon the chemistry of it's legs and what it's been walking in.

One of http://www.bio.miami.edu/~cmallery/150/chemistry/c3x3waterbug.jpg" should manage to sit on a soap membrane.
 
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People are not considering the fact that soap bubbles have *two* interfaces; the soapy water is a thin film.

Given that the interfacial energy of pure water in air is about 70 dyn/cm (70 erg/cm^2), say the interfacial energy of soapy water about 10 dyn/cm.

An ant weighs about 3 mg, so each 'foot' has 0.5 mg spread over (say) 0.1 mm^2. 'g' ~ 1000 cm/s^2, so each foot exerts about 0.5 dyn/mm^2 (5*10^-3 dyn/cm^2) pressure.

The pressure jump across one interface of a 5 cm diameter soap bubble is 2* 10 dyn/cm * (2/2.5 cm) = 16*dyn/cm^2. This is much higher than the foot pressure of an ant, so the ant's weight should be supported by the bubble.
 
Usually I have to keep things super clean or else ants will take over, but now that I'm actually looking for sugar ants to drop on a soap bubble, I can't find any.

:/
 
maze said:
Usually I have to keep things super clean or else ants will take over, but now that I'm actually looking for sugar ants to drop on a soap bubble, I can't find any.

:/

Check outside near the cracks of sidewalks or near the crevices of a patio
 
Put a piece of food on the ground and wait 30 minutes
 
  • #10
Andy Resnick said:
People are not considering the fact that soap bubbles have *two* interfaces; the soapy water is a thin film.

Given that the interfacial energy of pure water in air is about 70 dyn/cm (70 erg/cm^2), say the interfacial energy of soapy water about 10 dyn/cm.

An ant weighs about 3 mg, so each 'foot' has 0.5 mg spread over (say) 0.1 mm^2. 'g' ~ 1000 cm/s^2, so each foot exerts about 0.5 dyn/mm^2 (5*10^-3 dyn/cm^2) pressure.

The pressure jump across one interface of a 5 cm diameter soap bubble is 2* 10 dyn/cm * (2/2.5 cm) = 16*dyn/cm^2. This is much higher than the foot pressure of an ant, so the ant's weight should be supported by the bubble.

Thanks, you taught me ants have 6 legs. I never reely noticed:approve:
 
  • #11
Ok, I found an ant and dropped it on a soap foam. The bubbles were about 1/2 the size of the ant (ie: 2 bubbles = 1 ant).

The ant basically got stuck in the top layer of foam, immobilized. I believe its body geometry was serving as boundary conditions for the foam surface. After about a second of just sitting there, it spazzed out kicking its legs every way, which caused it to sink slightly to the 2nd or 3rd layer, and then after a couple seconds it stopped moving so I took it out. I think it died, which I didn't expect to happen (especially not after only a few seconds). I don't think I will be trying again since it seems a pretty cruel way to go.
 
  • #12
maze said:
Ok, I found an ant and dropped it on a soap foam. The bubbles were about 1/2 the size of the ant (ie: 2 bubbles = 1 ant).

The ant basically got stuck in the top layer of foam, immobilized. I believe its body geometry was serving as boundary conditions for the foam surface. After about a second of just sitting there, it spazzed out kicking its legs every way, which caused it to sink slightly to the 2nd or 3rd layer, and then after a couple seconds it stopped moving so I took it out. I think it died, which I didn't expect to happen (especially not after only a few seconds). I don't think I will be trying again since it seems a pretty cruel way to go.

Thanks for the update as this certainly is interesting.
 

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