How is it that bugs take no fall damage?
In: Physics
If you get scaled down so you’re half the height, you’re 1/4 as strong, and have 1/4 the surface area, but you’re only 1/8 as heavy. This continues the smaller you go. For a very small bug, you might have a surface area to weight ratio similar to a sheet of paper.
Smaller things are stronger relative to their size.
Some effects and forces dominate at different size scales. Like how an ant can carry 10-50 times their body weight. And grasshoppers can jump so far compared to their size. And why bugs find water to be very gloopy.
Suppose that a thing has length ***L***. It then has area ***L******^(2,)*** ***and volume L******^(3)***. Now imagine increasing L and see what happens to each. Area increases more than length, and volume increases even faster. Some effects may depend upon area, some on volume, and so the relative strength of these changes at different size scales.
The mass and weight will scale with it’s volume. But the strength the material it’s made of will scale with area (think of the thickness of an iron rod). So bugs are very tough and strong for their weight.
Also, the air resistance they feel scales with area, so they will fall slower and fly easier.
There’s a very useful thought tool called “squares versus cubes”. The idea is that if one property is proportional to the square of something, and another property is related to the cube of something, you can pretty much ignore everything else.
In this case, the mass an object (an insect, in this case, but the same applies to all objects) is roughly proportional to the cube of its length, because stuff on the inside has mass. And the drag that an object experiences is roughly proportional to the square of its length, since it’s only the leading surface that has to push through air.
So the bigger a thing gets, the less drag matters, and conversely, the smaller a thing gets, the more drag matters. Bugs, being very small, are greatly slowed by the air they’re falling through because the ratio of their mass (which gravity pulls against) to their area (which wind pushes against) is small.
Their body can take the proportional impact force of freefall on earth. This is because of the square cube law. As an organism gains surface area by 1, it’s volume increases 3. Smaller organisms terminal velocity with their mass doesn’t create a disproportionate impact.
If an object gets larger and maintains the same density, the volume of that object increases much faster than its surface area. Or, as the outside of something grows, the inside grows way more.
The bigger the thing, the more gravity affects it. So, the smaller the thing, the less gravity affects it. Human go splat, ant go plop.
They aren’t very dense so they don’t hit the ground very hard. In scientific terms, their low terminal velocity and lack of mass mean there is not much force on them when they hit the ground.
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