The Physics of Ants [video](nytimes.com)
nytimes.com
The Physics of Ants [video]
http://www.nytimes.com/video/science/100000002605952/sciencetake-the-physics-of-ants.html
5 comments
When I posted this I also had a thought that despite taking standard metrics of viscosity, elasticity, etc. it seems like it would be very difficult to model something like a glob of ants since each ant is obviously a lot more complex than a molecule. Perhaps, as a material scientist, you could speak to the difficulty of doing this?
This is off the top of my head and with no knowledge of the progress of the work done already on the topic... so please take this with a grain of salt!
I would be inclined to try to develop a model of the system and see if I could reproduce the measured viscosity and elastic properties from a simulation. From there you can do things like free energy calculations and figure out which ant-phase is the most stable under which conditions.
You're right that in reality each ant is much much more complex than a molecule. But since we're scientists we get to approximate (hooray for spherical cows).
To build the model you just treat each ant as an elastic ellipsoid with directional bonding properties. You start off by ignoring the legs and ignoring or greatly simplifying the motion of each individual ant. The first hurdle would be to figure out an ant's bonding properties as this is crucial to the stability of the total structure's properties. Play around with that until your simulation starts reproducing reality; add complexity as necessary; iterate and repeat.
As far as experimental measurements, I couldn't even guess what to do next without reading some of their publications.
I would be inclined to try to develop a model of the system and see if I could reproduce the measured viscosity and elastic properties from a simulation. From there you can do things like free energy calculations and figure out which ant-phase is the most stable under which conditions.
You're right that in reality each ant is much much more complex than a molecule. But since we're scientists we get to approximate (hooray for spherical cows).
To build the model you just treat each ant as an elastic ellipsoid with directional bonding properties. You start off by ignoring the legs and ignoring or greatly simplifying the motion of each individual ant. The first hurdle would be to figure out an ant's bonding properties as this is crucial to the stability of the total structure's properties. Play around with that until your simulation starts reproducing reality; add complexity as necessary; iterate and repeat.
As far as experimental measurements, I couldn't even guess what to do next without reading some of their publications.
I had a lot of fun writing an ant foraging simulation a year ago:
http://andrewcantino.com/?open=showAnts
Ants are super cool!
http://andrewcantino.com/?open=showAnts
Ants are super cool!
Is their sense of orientation really that great? In your simulation, when a wandering ant finds food, it heads right back to the anthill in a straight line. All I know from this is from reading about Feynman's experiments, but what he says seems to be more realistic:
One question that I wondered about was why the ant trails look so straight and nice. The ants look as if they know what they're doing, as if they have a good sense of geometry. Yet the experiments that I did to try to demonstrate their sense of geometry didn't work. Many years later, when I was at Caltech … some ants came out around the bathtub… I put some sugar on the other end of the bathtub… The moment the ant found the sugar, I picked up a colored pencil … and behind where the ant went I drew a line so I could tell where his trail was. The ant wandered a little bit wrong to get back to the hole, so the line was quite wiggly, unlike a typical ant trail.
When the next ant to find the sugar began to go back, I marked his trail with another color… he followed the first ant's return trail back, rather than his own incoming trail. (My theory is that when an ant has found some food, he leaves a much stronger trail than when he's just wandering around.) This second ant was in a great hurry and followed, pretty much, the original trail. But because he was going so fast he would go straight out, as if he were coasting, when the trail was wiggly. Often, as the ant was "coasting," he would find the trail again. Already it was apparent that the second ant's return was slightly straighter. With successive ants the same "improvement" of the trail by hurriedly and carelessly "following" it occurred. I followed eight or ten ants with my pencil until their trails became a neat line right along the bathtub.
One question that I wondered about was why the ant trails look so straight and nice. The ants look as if they know what they're doing, as if they have a good sense of geometry. Yet the experiments that I did to try to demonstrate their sense of geometry didn't work. Many years later, when I was at Caltech … some ants came out around the bathtub… I put some sugar on the other end of the bathtub… The moment the ant found the sugar, I picked up a colored pencil … and behind where the ant went I drew a line so I could tell where his trail was. The ant wandered a little bit wrong to get back to the hole, so the line was quite wiggly, unlike a typical ant trail.
When the next ant to find the sugar began to go back, I marked his trail with another color… he followed the first ant's return trail back, rather than his own incoming trail. (My theory is that when an ant has found some food, he leaves a much stronger trail than when he's just wandering around.) This second ant was in a great hurry and followed, pretty much, the original trail. But because he was going so fast he would go straight out, as if he were coasting, when the trail was wiggly. Often, as the ant was "coasting," he would find the trail again. Already it was apparent that the second ant's return was slightly straighter. With successive ants the same "improvement" of the trail by hurriedly and carelessly "following" it occurred. I followed eight or ten ants with my pencil until their trails became a neat line right along the bathtub.
I don't get why this is an interesting study. Can somebody explain me?
Look to the end of the video -- these sorts of studies could tell us more about making interesting new materials or perhaps small robots that can behave similarly when clumped together.
Fantastic! After all these years of watching all sorts of interesting ant behaviour, that's a new perspective.
On a side note I am really frustrated with the NYTimes video service, I have never had one of their videos play through without freezing!