# Ant soap bubble

maze
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?

Gold Member
you can touch bubbles with out them bursting, so I guess an ant could.
Find an ant, make a bubble, put the ant on it. It might even work :D

Oscar Wilde
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.

Phrak
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" [Broken] 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.

maze
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.

:/

Oscar Wilde
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

junglebeast
Put a piece of food on the ground and wait 30 minutes

johnsmi
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

maze
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.

Oscar Wilde
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.