I’ve wondered about this for a long time. Ants seem to stop on a dime, so to speak, when they’re moving about. From our perspective, they don’t seem to jiggle or shake at all to disperse their energy of motion, and the ground certainly doesn’t move. So, how do they stop so suddenly, and why don’t their little brains bang against their tiny little skulls when they stop so suddenly? What happens to all that inertia?
For one thing, they don’t have much mass. There’s not much to rattle around.
For another, I don’t think they have brains in the traditional sense that mammals do. They don’t have tiny little brains inside of tiny little skulls.
I suspect that for an ant, the difference between being brain-addled and normal functioning is not great.
Regards,
Shodan
I doubt we could tell whether the mass of something so small was jiggling or shaking to disperse energy in motion–especially since in my experience ants hardly ever stop moving for more than a split second, making the discernment of “jiggling” even more difficult.
-FrL-
“Gotta bring the giant leaf to the queen. Gotta bring the giant leaf to the queen. Gotta bring the giant leaf to the queen. Oops. Hey, where was I going, again?”
But think about it. Suppose you were walking along veeeeerrrry slowly, and then you stopped. How much shock to your system would that create? Now thin, how fast is that ant going? That ant is actually traveling very very slowly.
If you enlarged the ant to human size, and it were traveling at the same proportionate speed, and stopped at the same proportionate time, then the ant would be stopping suddenly. But that ant ain’t human size, it’s what we scientists call very very small, and it’s travelling very very slowly. So when it stops, it’s going from .01 mph to 0 mph. That’s not much of a change. And the ant masses only a tiny tiny amount, so its inertia is very very small. Small mass, small speed means when you make very very small changes to that speed you only need very very very very small amounts of energy.
Sure, but the amount of energy required is reduced in proportion to its size.
Pick up ant.
Put in model airplane
Put plane on very fast moving treadmill.
Stop treadmill suddenly.
Check out ant’s brain.
It’s not a virus, I’m afraid.
“An ant is a ganglion with legs”
I don’t recall who said that, but it’s pretty close to true.
This is dangerous territory around here…
This, from The Lives of a Cell, might be it:
Send it to the Marianas Trench for 20 minutes. That ought to addle its little ganglion good!
But people who are going really fast and then suddenly stop don’t get brain addled…at least, I don’t. Why should ants?
I was going to say the same thing, but I’ve fallen on my butt a few times. I was a bit stunned.
A 1/4 inch ant can reach around .25 mph. If you could find an ant that was as long as a human male is tall (say, 72 inches), it could theoretically reach 70 miles per hour*. Think about what happens to a car when it instantly decelerates from 70-0…
Olympic sprinters can cover 100m in ~10 seconds, which is only 27 miles per hour.
*I say theoretically because a 72-inch ant wouldn’t be able to breathe at sea level. That’s why we have no giant bugs anymore- because the concentration of oxygen in Earth’s atmosphere is much lower than it used to be.
Look, ants just don’t move very fast. You bend down and look at them, and it seems as though they’re zooming along. But if you back up and measure how fast they’re actually moving, they are moving very slowly. Like, much slower than a human walk. They only look like they’re moving fast because they move fast in proportion to their size. If a 1 meter dog moves 10 body lengths in 1 second, it’s moving 10 m/sec. If a 1 cm ant moves 10 body lengths in 1 second, it’s moving 0.1 m/sec. A dog moving .1 m/sec that stopped suddenly wouldn’t get dizzy, would it? So why should an ant?
How is this relevant? It’s not that big and it’s not going that fast.
I’m with Freudian, I dont’ get brain-addled when I slam the brakes on my car, why should ants. ** tdn **speaks of falling on his bum, but that’s different than stopping under your own power.
Long story short, even if an ant weighed a full gram and was traveling a full meter per second, it’s still only got to disperse .001 joules. Not very much at all.
ETA: What Lemur said.
It would also be 23,887,872 times its previous mass (because it expanded 288 times in three dimensions). Such an ant who previously weighed 1/20 of an ounce would now weigh 37 tons, requiring a cool million newtons of force to move and 1,998 horsepower to do the quarter-mile.
Those silly numbers illustrate the danger of trying to scale human-size physics to ant-size. Relative speed aside, ants have much less mass.
If we could watch an ant on teflon, or some very low friction surface, would we notice it skid when it stopped? Or is its tiny mass and speed so small that it has almost no inertia?