Eli5 how can insects survive a slap from humans, a creature that’s gigantic compared to them


Eli5 how can insects survive a slap from humans, a creature that’s gigantic compared to them

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They are very small and light. At their size, the stuff they’re made of is strong compared to the forces it needs to withstand (like their own inertia). This means that they’re more likely to bounce off than break.

It’s sort of like comparing a wooden locket and a wooden house being hit by a wrecking ball. The wooden locket will bounce off, maybe getting a few chips as it hits the ground. The wooden house gets obliterated.

That’s because very little of the wrecking balls energy got delivered to the locker before it harmlessly bounced, it was very easy to move. Meanwhile the large house’s own inertia prevented it from just moving, while the material it was made of wasn’t strong enough to withstand the force that WOULD move it. So it caved in instead.

Assuming you’re slapping them out of the air, your moving hand is also moving a wall of air in front of it. The wall of air first hits the insect and starts pushing it forward. Now you’re trying to slap something also moving in the same direction. This transfers less force than slapping something staying still.

The wall of air can also cause the insect to blow around your hands, especially if the insect is small.

You’ll notice fly swatters have holes in them to prevent this wall of air. It’s much easier to swat insects out of the air with them than with your hands.

Though in either case, if you swat them against something hard, they have no where to go and they get the full force.

As an example of fleas.


Fleas are small and light. Their chitin can withstand a lot of weight for how small they are.


Your fingers and flesh are soft and dampen the amount of force you can apply.


So no matter how hard you try, slapping or crushing a flea with your fingers or palm is difficult or impossible. Squeezing a flea between two fingers is unlikely to kill it.


However, if you crushed a flea between your finger nails…. Well your finger nails aren’t soft like your skin. And you’ll crush it.


So if you flicked an insect with your fingernail, you’ll probably kill it.

But if you tried to palm crush an insect, it might just survive.

To add to what the others have said. Your hand is big with gaps between fingers etc. Bugs are small. So you might smack a bug on your arm and the bug is in the gap between your fingers. Being small can have some advantages. That said, there is some sort of beetle here in Texas, and you can step on it with your shoe and it doesn’t work. The thing is small but a tank.

It’s hard to crush small things in general. It’s hard to focus the force into something hard and tiny, your soft meat kinda just flops around it instead of transferring a lot of force to the thing.

If you hit a tiny seed in mostly won’t do anything, you have to squeeze it between things to crack it. A lot of bugs are small, Have a hardish shell and are flat like the seed. Your hand don’t focus much energy into it