Or, more specifically, how to kill people with it!*
Sound, as we all know, is a physical thing. It comes from vibrations moving through matter (including air, of course). A sound begins when something causes a vibration. This vibration creates a longitudinal wave traveling through matter. This wave is actually a pressure wave. If said pressure wave hits our eardrums, then we hear a sound.
The volume or loudness of a sound is based on the amplitude of these vibration-created pressure waves. A loud sound will have a larger oscillation between the high and low pressures of the waves when compared to a soft sound, meaning that loud sounds have higher high pressure sections and lower low pressure sections than soft sounds.
This is kind of convenient because it allows there to be a threshold for what we can consider to be the “loudest” sound—if the low pressure gets too low, it hits vacuum-level and cannot go lower. So the loudest sound is something that creates low pressure sections between waves that are nearly vacuums.
In fact, what we consider to be the “threshold of sound” on the loud side of the scale (at least on earth) occurs at 194 decibels.** And where do we hit the point where sound can be deadly? Somewhere around 185-200 decibels.
It’s actually kind of disturbing to think about. But also really cool.
*Sound killing people was actually something I focused on in my 2012 NaNoWriMo, “Whistler’s Father.” A scientist and an artist were working together to create the “perfect” sound—something that would boost mood, health, and would overall make people “better” if they were to hear it. But it turned out that the perfect sound was actually deadly if it was listened to for too long; the scientist in my story ends up killing himself via this perfect sound because he becomes addicted to it and is unable to stop listening to it in time to prevent his own death. Yeah, that was a cheery NaNo.
**You can get sounds louder than this, but the vibrations that create them don’t create waves (again, because of that low pressure threshold) but they still create something. Things like the atomic bombs dropped on Japan and the eruption of Krakatoa, for example, were louder than 194 decibels, and were very destructive if we even just consider the sounds (or rather, the spikes in atmospheric pressure) they produced.
It talks about a study that focused on comparing the hearts of chimps, gorillas, and humans (classed as one of the following: endurance athletes, football linemen, farmers, and inactive people). The researchers wanted to look further into human’s rather unique endurance ability – our ability to run/walk long distances.
For the gorillas and chimps, they spend a lot of time sleeping or just generally being inactive and have occasional quick bursts of energy and stress (such as quickly climbing trees or fighting). The researchers believed that these quick bursts caused spikes in blood pressure, but found that the shape of the gorilla and chimp hearts were suited well for these spikes. The hearts were round and had thick walls.
The human heart is different. It is larger than chimps’ hearts and less thick and also twists/rotates when it pumps blood (the gorilla and chimp hearts don’t). This allows for a more efficient blood delivery system and is ideal for endurance activities. The trade-off, though, is that the walls of the human heart aren’t as thick and thus are not as well-built for sudden blood pressure spikes.
Another interesting finding from the research is that if a person tends to live a sedentary life, their heart will “remodel” itself and become more like a chimp heart: less flexible with thicker walls. These hearts also appear to look like the hearts of people with chronic high blood pressure even before high blood pressure actually sets in.
They use this finding to emphasize the importance of regular exercise, noting that previous research showed that hunter-gatherers (in certain areas) tended to walk somewhere between six and nine miles a day. Physical activity, as we’ve all been told, is key to maintaining the flexibility and durability of the human heart.
Do any of my readers remember hearing about this when it happened in 2006? I certainly don’t remember hearing about it, but I was in high school and gave zero craps about anything that wasn’t The Sims or stalking Lead.
But this is a really well-done documentary, yo. Check it out and be terrified.
Holy crapples, guys, so you know how I was talking about the kilogram (again) the other day?
I HAVE FOUND THE JOURNAL TO END ALL JOURNALS
Metrologia is a journal about the scientific aspects of measurement – most commonly those involving the seven base SI units.
Here’s an article talking about the kilogram.
I will disappear into this journal forever now, bye.
So once again, while Nate and I were playing an old Jeopardy game, the topic of the kilogram came up (there was a “Weights and Measures” category, so I’m not totally to blame this time). I was blabbing on about Le Grand K, the physical kilogram (THE kilogram…at least until it was redefined) and said something to the effect of “I guess they’re not going to be using that anymore…I want it!”
Like, can you even imagine sending an email to the International Bureau of Weights and Measures that read something like:
To Whom It May Concern,
So I just heard the big news that the kilogram is now defined based in part on the Planck constant, rendering the International Prototype of the Kilogram obsolete.
Now I’m just some pleb, but here me out: if y’all aren’t using the IPK anymore, I’d be happy to take it off your hands. I’ve got a nice space for it on my trinket shelf, and it would help de-clutter things for you now that the kilogram is no longer technically defined by an artifact.
Anyway, think about it. I can pay for the shipping costs, too, if that would sway your decision!
Thank you for your time,
The idea of some random person just emailing the Bureau of Weights and Measures to ask if they could have the IPK is absolutely hilarious to me.
‘Cause I have that kind of dumb sense of humor.
I really like this explanation of why Fahrenheit is a good “understandable” temperature scale, even though its set points of 0 and 100 are kinda wonky. It’s practical and intuitive for human “day-to-day” use. It’s also more precise.
I love me a kilogram, but I’ll be damned if I ever support Celsius.
(And yes, I know I take this stuff way too seriously.)
Let’s look at the super cool ISOCHRONOUS CURVE!
This video does a good job of demonstrating that the periodic motion of an object on a (frictionless) isochronous curve has a period that is independent of where the object starts on the curve. It’s a pretty cool little thing.
Edit: OH MY GOD, A WHOLE WEBSITE ABOUT CURVES AND SHAPES
(I’m going to link to one of the pages, ‘cause it looks like the majority of the site is in French, but some of it has been translated to English. I’ve clicked through a lot of the curves using the links at the bottom and I’ve only hit English pages, so if you want to look at some curves, that might be the best way to go (unless you know French)).
This guy’s absolute adoration of laminar flow is so freaking awesome.
Is…is this how I am with Leibniz?
This makes me abnormally excited. I don’t know what it is with me and the SI units, but I dig ‘em, man.
And let’s be honest: I searched “kilogram” and read every related bit of info that came up, ‘cause the kilogram is my bro.
Basically, pupil shape is at least somewhat tied to whether an animal is more of a (grazing) prey animal or more of a predator. The article talks a lot about goats and sheep, and goats and sheep are pretty cool, so if you’re not into pupils, maybe you’re into goats and sheep.
(Sorry, I haven’t slept in like three days)
I love this guy’s video simulations of space stuff.
I also love the disclaimer “Saturns rotation is extra impossible, but I had to prevent the rings from colliding.”
Don’t we all, yeti dynamics? Don’t we all?
So y’all know I love the SI units, right? Hell, the “kilogram” tag on this blog is used frequently enough that it shows up in the “Tags” list on my front page.
Well, another closely-related thing I love are the SI prefixes. These are things like kilo or nano or yocto (which got its own blog a while back) that precede a unit and indicate either a multiple (like “kilo” suggests a thousand times something) or a fraction (like “milli” suggests a millionth of something) of the unit. Kilogram, nanosecond, millimeter, etc.
That kinda stuff.
Well, I guess four new prefixes have been proposed for the next levels of super big and super small: ronna and ronto for 1027 and 10-27 respectively, and quecca and quento for 1030 and 10-30, respectively. If they’re approved, they’re set to be officially put into place in 2022, making them the first prefixes approved since 1991.
And that is way too cool.
(I love the prefixes and I’m not sorry.)
Alternate title: GOD I’M OBNOXIOUS
Hokay. So Nate and I were playing Jeopardy this evening and some question* came up that made me think of the kilogram. This got me ranting and raving about said kilogram, as I am wont to do, so I looked it up on my phone because I knew that there have been recent attempts to redefine the kilogram based on a physical constant and I wanted to see exactly what that redefinition would be.
This eventually led to looking up the Planck constant, which led to viewing this equation:
Of course it’s the mobile version of Wiki so it scrolls right in order for you to view the rest of the equation, but I initially didn’t think of that and I thought it was beyond hilarious that the Planck constant equaled 4.1. 4.1 what? Who the hell knows, that’s why it was funny.
*I can’t recall the specifics of the question, because like any well-adjusted happy person, I gloss over large amounts of my existence so that it’ll feel like I reach death faster.
Remember that bomb blast simulation I mentioned a few days ago? They have an interactive “how will climate change affect you?” map as well.
So this is a cool little website. It lets you type in a city and highlights places around the world that have similar climates to that city.
Here’s Calgary, with its Dfb Koppen climate (continental climate, no dry season, warm summer)
Moscow, with its Csb Koppen (middle latitude climate, dry season in a warm summer)
Vancouver, with its Cfb Koppen (middle latitude climate, hell on earth no dry season, warm summer)
And Tucson, with its BSh Koppen (dry and hot semi-arid climate)
Have you ever seen a canopy like this?
(Picture from here)
What’s going on with those gaps between the leaves/branches? Turns out there’s this thing called “crown shyness,” a phenomenon observed in some species of trees. The phenomenon occurs when different trees’ crowns do not touch each other, leaving these funky channels of gaps between the crowns.
No one really knows what causes this crown shyness. One theory is that the behavior is adaptive, helping to prevent the spread of bugs/larvae that eat leaves. Another theory is that the behavior develops due to the fact that too-close branches can be damaged in storms and high winds from bonking into one another. Still another theory has to do with light. The behavior develops to help ensure that the leaves of a tree are not blocked by the shade of another tree’s leaves, thus getting an optimal chance for light.
So this thing is incredibly educational and awesome.
But the immature side of me cannot stop laughing.
Fun fact: if you move the “tongue control” dial clockwise in the triangle, you get continuous “oohhhhhh yeeeeeahhh!”
Moving it counter clockwise get you continuous “IIIIIIIIII knoooooooow!”
So I have no idea how I’ve never found this podcast before since it’s about the kilogram, but I haven’t.
But now I have.
(Hot damn, I love the kilogram.)
So as you all know, I find the sun to be very awesome. Here’s a video of a guy demonstrating that despite the fact that the sun seems so huge in our sky a lot of the time, that hugeness is an illusion! The sun is, in fact, only about half a degree in size in our sky.