I keep wondering this. Having a fruit fly problem at the moment, so I got regular experience with this. Let's say it's flying through the air and I give it the biggest bitch slap you can imagine. Now, if you consider scale, this would be like a human punched by something 10x the size of King Kong. That would obviously mean instant death. How come they don't get hurt and just die on impact?
Posted Sep 22, 2023, 11:52 PM UTC
Bugs are built like tanks. They're armoured to fuck.
They weigh too little. When you swing at them, the air in front of your hand actually pushes them out of the way.
sounds like somebody spent an hour trying to kill a slow flying moth
they are so small, that the Air that is being pushed out of the way of your hand, is enough to push the fly out of the way/keep it from getting really damaged
What about a regular fly. Sometimes I hit them and I can feel I made contact, but they still just carry on with their day like they didn't just survive an assassination attempt.
the air is cushioning your blow.
What a fuck I hate air now. What a betrayal.
Flies are the devils best invention of course they’re hard to kill
I recommend an electric racket.
F=ma.
m is the inertial mass of the object. The larger the mass, the larger the force related to acceleration.
Fruit flies have a very small mass, and therefore are easily accelerated, especially midair, without experiencing much force. For a human this isn't the case, something like our brain for instance will experience severe force from acceleration which can cause concussions or death due to acceleration.
The inverse square law.
Take something that is one foot thick, one foot wide, and 10 feet tall. Make it only just barely strong enough to support itself standing up safely.
Now, double all the dimensions. It is now two feet thick, two feet wide, and 20 feet tall. It collapses immediately.
Why? Well, it is twice as thick, and thus twice as strong and heavy from thickness. It is twice as wide, and thus twice as strong and heavy from width. These multiply together, so it is four times stronger.
However, it is also twice as tall. This doesn't make it stronger, but it doubles the weight as well. Two (thicknesses) times two (widths) times two (heights) is eight times the weight.
It is four times stronger but eight times heavier. This has the same effect as doubling the weight while leaving everything else alone, so it collapses.
However, this works the other way, too. If you make it only half a foot thick, half a foot wide, and five feet tall, it would be one-fourth the strength but one-eighth the weight. It would now be twice as strong for its size.
Each time you halve the size, its strength for its weight doubles. This is why people talk about how strong spiders and ants are for their size.
How does this matter when being smacked?
When you smack something with a much larger thing, the impact is greater the more the thing being hit weighs in much the same way as what we just described. If I hit something so hard I send it flying, the heavier it is, the less it just flies through the air and the more it is smashed. Think of the difference between hitting a ping-pong ball and an egg of similar size. The light ping-pong ball goes flying and the heavier egg goes splat.
The same applies to creatures. An impact that crushes a human being sends the fly flying harmlessly because each time you halve the size of the larger creature (the human), you get twice the strength for the weight. If cutting you down to the size of a fly were to mean you got divided into half seven times, you would be twice as strong for each halving, or 128 times stronger for your weight.
This is a gross oversimplification and ignores a lot of things. None of them matters nearly as much as the inverse square law, however. The inverse square law rules here.
Exactly this. Same reason ants can carry 20 times their weight, while whale sized animals can only survive in water. And yes, that's also valid for the bigger, heavier dinosaurs. And Gojira.
I forget where I read it, but I remember someone talking about a movie they saw with a giant squid monster attacking a bridge, the Golden Gate, I believe.
The author said that they lost the suspension of disbelief because of how impossible it would be to lift tentacles that far out of the water. They went on to say that the monster then became almost inert until it was blown up, which they attributed to the weight of all the blood in the tentacles causing a brain aneurism.
Hahaha, I love that. Yeah, lift a tentacle up to 100m above your brain/heart and add another 10 bar to the pressure down there. 100 tons per m² (not sure what that is in fairy-pushes per square cubit or whatever the US equivalent is, but).. that's quite a headache.
Between different engineering applications, sciences, medical applications, and just weirdness, we have quite a few. Pounds per square inch, millimeters of mercury, atmospheres, the bar which is atmospheres rounded off to 100,000 pascals, etc. Oh, and we use pascals, too, which are the SI units.
Materials don’t scale the same way forces do, if that makes sense. Chitin (the stuff bugs exoskeleton is made of) is strong. Bugs are tiny so the amount of force needed to move them is also small. So when you smack em, the initial impact isn’t enough to break the chitin, so most of the force just moves the bug.
If you made a bug that’s human sized and King Kong smacked it out of the sky, it would mean instant death because the forces involved would easily overcome the strength of chitin and they’d splat.
Another way to think about it is of you dropped a mouse from the roof. It would be 100% fine because bones are super strong relative to the mass of a mouse. If you dropped a person, they might break some bones. If you dropped an elephant, they’d definitely break bones and probably die.
At that scale it doesn't have much inertia so it doesn't resist forces that change its direction very much. Smacking it will just change its direction without imparting much energy into its body. You need to crush it between two objects to prevent this.