Chin -> Penguin

Chins are funny. Every human has one; no human knows why.

No other primate (extinct or extant) has a chin. Everyone else’s mouth curves inward at the bottom, making chins a curiously and uniquely human trait. There are a few popular ideas for why chins evolved, but none of them holds water. Or food. None of them holds whatever’s in your mouth like your trusty chin does. The proposals that say chins served an evolutionary purpose (whether mechanical or sexual) don’t hold up to scrutiny, while what seems like the best idea (that chins were simply exposed as our ancestors’ faces shrunk) is difficult to prove. It’s a chin-undrum. (That’s conundrum, but chin.)

All I know, really, is that when I’m outside in a blizzard, I need to keep my chin covered because of our old friend the square-cube law. Chins have a lot of surface area, so they lose heat quickly, but they only get warmed at the same rate as the rest of the body (which has less surface area compared to its volume than a chin does). Combine those and it means that chins, ears, fingers, toes, and noses lose heat faster than it’s supplied.

Emperor Penguins have learned the square-cube law, too; it’s why they huddle by the thousands through the Antarctic winter instead of letting every individual fend for themselves. Each member of the huddle has some of their body exposed to the wind and some exposed to other (warm) penguins. Less heat escapes to the wind than it would if everyone were alone. This shielding works so well, in fact, that the penguins at the center of the huddle can get too warm! They move away from the middle to cool off.

When they move to the edge, those on the edge get to shuffle their way toward the middle. They get to warm up and stay alive after bearing the brunt of the cold, the same way members of a household might rotate shoveling duty when it’s really cold outside so that no one gets frostbitten.

At least, that’s the hope—in both cases.

Blizzard -> Tank

Growing up, I thought adults who said “nor’easter” were bad at saying “northeaster”. I was wrong.

Just about all nor’easters—a sort of winter tropical storm, for those not from New England—count as blizzards. But a blizzard is more than a bad snowstorm. It’s a winter storm with high winds and enough snow in the air to keep visibility fairly low for at least three hours. Since light bounces off snowflakes, the more snow in the air, the closer something has to be for most its light to get to you without being bounced all over the place first. Whether that snow came from the clouds or it was picked up from the ground by wind doesn’t come into play in defining the storm.

Snow muffles sounds just as it bounces light, but for a different reason. The coordinated vibration of molecules that forms a sound jiggles water molecules in the snow around and becomes random vibrations (heat). (Also, winter storms tend to have funny temperature distributions that refract sound upwards and away from our ears.) During a blizzard, with howling winds and sound-absorbing snow everywhere, you can only hear really loud stuff from afar—loud stuff like thundersnow.

But sounds dissipate with distance even without snow. Some of the coordinated vibration of a sound wave always turns into heat as sound travels through the air. Higher frequencies are especially susceptible: They start with more rapid vibrations at the outset, so it’s easy for those to get out of sync and become random noise. Also, it takes more energy to sustain more rapid vibrations, so the sound runs out of energy sooner. This means treble dissipates too quickly to be heard from a great distance. The farther you are from something, as a result, the lower-pitch it tends to sound. (Side note: This is also why people who live upstairs from you always tend so sound like they’re stomping and grunting rather than squeaking.) (Second side note: This is tangentially related to something I talked about for the Museum of Science [24:17 in that video is the question and then my answer], where you can tell the angle of a lightning bolt from the sound of the thunder.)

What’s true for natural processes is also true for natural processes that humans have a hand in—there’s nothing to be gained in separating us from nature, after all. So if you’re far from an outdoor concert, you’ll hear more bass drums, low voices, and low guitar chords. And if you’re close to a tank when it fires out of the big barrel, you’ll hear a wide spectrum of noises. But if you’re a ways away, you’ll mainly hear a boom. Hopefully you’re far away in the right direction.