Main Question or Discussion Point
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?
Thanks, you taught me ants have 6 legs. I never reely noticedPeople 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 for the update as this certainly is interesting.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.