maze
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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?
The discussion explores whether a tiny sugar ant can walk on a soap bubble, considering the physical interactions between the ant and the bubble's surface. Participants examine the implications of surface tension, gravity, and the ant's weight, as well as the potential outcomes of such an experiment.
Participants do not reach a consensus on whether an ant can successfully walk on a soap bubble, with multiple competing views on the feasibility and outcomes of such an interaction.
Some discussions involve assumptions about the physical properties of soap bubbles and the ant's interaction with them, including the effects of surface tension and gravity. The outcomes of personal experiments are anecdotal and may not represent broader conclusions.
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.
:/
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.

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.