In the last season of the show, Mythbusters, they pulled out all the stops. And its third episode was one of the biggest stunts they ever pulled.
In every episode of Mythbusters, of course, there has to be a myth for them to test. And in this episode, it was this:
Not too long ago, there was a guy who worked at a railyard. Like most rail yards, railroad tracks criss-crossed each other in a tangled web crowded with railroad cars. That was where these cars got loaded and unloaded and sorted and stored and cleaned … and one dreary day, this guy went out to clean a tanker car. Now, a tanker car is just like what it sounds … a giant cylindrical tank on wheels, like a 60-foot long barrel tilted on its side. On the top of this tanker card is a hatch. And it was the job of our railyard guy to climb up onto this tanker car, open the hatch, and steam clean the insides.
So … on this particular day … a dreary, overcast day … the railyard guy is steam cleaning a tanker car when it starts to rain. He’s just about done anyway. So, he finishes up, closes up the hatch, and climbs down to find someplace dry.
The next morning, according to the legend, his co-workers show up to the railyard to find that particular tanker car … the one our railyard guy had cleaned the previous night … was destroyed … completely demolished. Crunched like Godzilla has stepped on it.
And all of the workers are standing there scratching their heads … How could this have happened? These tanker cars are huge! One of them is almost as long as my house … fifteen feet tall … designed to withstand the forces of a rail collision … walls of steel nearly an inch thick! What! The! Heck!
The Mythbusters, in their effort to put this legend to the test, got their own tanker car. It took them several tries … but eventually they captured, on camera, the near-instantaneous implosion of an enormous tanker car. When it was all over, it looked as if the car had been stompled on by Godzilla. But, of course, it wasn’t Godzilla. That tanker car was crushed by something much more powerful than even the “king of monsters.” It was crushed … by the air.
Today, I’d like to talk about the air, what it is, how wondrous it is to live your life completely surrounded by a substance of such immense power, how air connects us in surprising ways, and finally, what air has to teach us about how to live a grateful life.
I’m fully expecting that it might be hard to convince you to care about this. I mean, look around you. No matter where you are in the world, I can bet that you can’t see air. You can smell it. You can’t taste it. The most that we tend to notice about that air is when there’s a strong wind or when the temperature is hot or cold. Air is the easiest thing to take for granted.
But I am hoping that by the end of this episode you will never think about air as just the backdrop for life on Earth again. I’d like to convince you that air is a wondrous power whose strangeness we fail to perceive not just because it is unseeable … but because we are habituated to it.
Counter argument: Air is really a kind of nothing Invisible, granted we need it to breathe, but just because you need something doesn’t really make it cool. Air is kind of a nothing. It’s almost not really real. Do you know what I mean?
Maybe. Are you saying that, like, air isn’t substantial, like wood or rock or water.
Yeah
And so that makes it less interesting?
Yeah, I guess so.
Well, then, why don’t we start with this. Here’s a problem that I give to science students in, like, 5th or 6th grade. I show everyone a deflated basketball. I’ve pushed all the air out so that it is squished and dented. And then I’ll put it on a balance or a scale and weigh it and write its weight on the board. Say, 550 grams. Then I propose this mystery. I show them a bicycle pump and I ask them what will happen to the weight of this basketball if I pump it full of air?
I have done this exercise maybe a dozen times, and almost every time, it stimulates a delightful and good-natured argument. Some students say the ball will get lighter. After all, air is the lightest thing. Won’t it bring “lightness” to the ball. Others say that the ball will get heavier. You’re adding something to it; it’s going to make the weight go up. Another group will say, “Wait! Why should air make a difference at all? Air is like nothing. Shouldn’t the basketball just weigh the same?” And often, there’s a contingent with perplexed looks on their faces who seem surprised that the question should be so hard.
This cuts to the heart of how mysterious air is. When I ask these students if air weighs something, it’s like asking if air is real in the first place. Is it stuff? Is there a there there?
And … after a fair bit of discussion, it becomes clear that, in the absence of further information, all of these ideas are reasonable. And there is only one way to resolve the question. We inflate the ball and put it on the balance … and the balance tips. Where before the ball was 550 g, now it is 558. Air weighs something. It is something real.
These results surprise people not because the numbers are particularly high. Most measurements of the air in a basketball that I’ve made have been under 15 grams. The reason they surprise students … I think … is because even though we know air is real in some kind of removed, abstract sense. We don’t act as if we really believe it. We forget … even though we’re surrounded by evidence that air IS real–that it’s NOT nothing. I mean, you’ve been surrounded for your whole life by rubber tires and basketballs. You’ve seen first-hand that air can fill something up. You’ve seen it burst balloons.
In the modern world we have all kinds of air containers like this and it’s STILL hard for us to appreciate the realness of air. Imagine how much harder it must have been for people who lived in times before bicycle pumps and rubber and balloons and zip-lock bags. For them, the realness of air wouldn’t have been obvious at all.
Even today, it helps to be confronted by evidence of air’s realness. So try this on for size.
Yeah. Yeah. I get all of that, but, like, it’s not like air is something you can hold in your hand. Even if it does weigh something it’s not like …I don’t know … glass or wood. You can’t hold a chunk of air in your hand. You can’t talk about its color.
Actually … what if I told you that you could?
Air can be turned into a liquid. Air can also freeze. Of course, the temperatures at which this happens are unthinkably cold. Even on the most frigid Antarctic night, air won’t even get close to liquefying. But us clever humans have done it. If you ever have a wart and go to the dermatologist to have it removed, you’ll get to experience liquid air first-hand. The doctor will bring a steaming, bubbling thermos into the exam room. It will be full of a clear liquid. That liquid is nitrogen, the major ingredient of air. It is liquid air! So cold that if, when the dermatologist dips a Q-tip into the container, she accidentally touches it to your skin it will feel like a burn … as the water in your cells instantaneously turns into ice and shatters the cell membranes, like a glass jar left in the freezer.
Or how about this. The second key ingredient of air is oxygen. When it is liquefied it turns a deep, glacial blue. A dish full of it is a beauty to behold. What we call “dry ice” is only dry because it contains no water. It is a frozen block of yet another air ingredient, carbon dioxide. To hold a brick of dry ice in your thickly-gloved hand, to feel the heft of it, is to never doubt the substantialness, the realness of air again.
(Okay, but maybe that kind of thing only happens in really weird conditions, right? Like in a lab or something. It’s not “normal.”
Well, maybe not here on Earth.)
On July 14, 2015, the New Horizons space probe passed the dwarf planet, Pluto, sending spectacular close-up pictures of its surface back to breathless onlookers here on Earth. From Pluto, the sun is so far away that it look like a bright, but otherwise unremarkable, star. Pluto’s average surface temperature is -387 degrees F. That’s only about 106 degrees above absolute zero. What I remember most about those pictures wasn’t glacial surface or the ice mountains. It was a couple of hazy white whisps floating in the threadbare Plutonian atmosphere. Could they be … clouds?
Scientists still aren’t sure. The pictures aren’t clear enough to really tell. But what if they were clouds? What would they be clouds of? Certainly not water droplets, like on our planet. On Pluto, water is just another kind of rock. It probably melts less often than granite does on Earth. If Pluto has clouds at all, it is possible that they are made of some of the same substances that make up air on Earth. Can you imagine? A place so cold that air itself falls as snow or forms as dew. Perhaps somewhere, maybe even right here in our own solar system, there are liquid rivers of air eroding hillsides and carrying sediments down to the shore of a brilliant blue oxygen-based ocean.
So … you convinced? Have I made air feel any more real for you?
Yes, definitely more real. … but …
But?
Well, what’s cool, I guess, is the weird things that could happen somewhere else to air. It’s not like the air right here is doing anything particularly cool.
So … like, it’d be pretty rad to pour air out of a pitcher if you could, but just being around “regular” air isn’t so hot.
Well, no, cause it’s not, like, doing anything.
We’ll what if I told you it was doing something?
Maybe we’d have more appreciation for the miracle of air if we had more occasions to play in places that didn’t have any. I’m not talking about suffocation here. By all means, go ahead and take your space suit. I’m just saying that there is nothing to reveal the awesomeness of air to be somewhere where they don’t have any.
Imagine for a second that I could snap my fingers and make the air disappear from Earth? What do you think would happen?
Students will sometimes say that we would float off into space, and while that would be awesome, it’s not true. Gravity doesn’t require air. You’d still walk and jump and land and fall as usual. But what would change would be totally weird. As listeners of our first episode will know, the blue sky would disappear and you would see the sun shining right out in space next to her sister stars in the blackness of space. Shadows would grow suddenly dark and crisp without air there to scatter the light into them. The line between light and darkness would become nearly absolute.
And the snap of my fingers that made the air disappear would be silent. All sound would stop except for the sounds within your own body. I could clap a pair of cymbals just inches from your ear and all you would hear was silence.
You could launch a rocket into space from this newly airless Earth. (In fact, it would be way easier.) If you dropped a feather and a hammer from a skyscraper, they would land at almost exactly the same time. But every plane would instantly fall out of the sky, and no amount of runway would be enough for another plane to take off.
Every fire on the planet would cease to burn–so no gas stoves. But electric stoves would work just fine. In fact, they’d stay hot longer without the air to conduct their heat away. And if dropped some paper onto that stovetop, instead of bursting into flames, the paper would char and decompose.
But again, that’s not something that you’d ever really see. Doesn’t “Nature abhor a vacuum?”
Not at all, most of the universe is empty of air. We just happen to live in this thin little envelope of it. Sound and sky and flight and fire are all weird things that only happen in the funny condition of living in air. If you found a race of creatures that lived in the void of space, they would doubtless buy tickets to see the weird things that happen in our air.
So, where did the idea that “nature abhors a vacuum” come from then?
Ooo, that’s really interesting and it brings us to maybe the coolest thing about living in air. So that expression came from, Aristotle, the ancient Greek philosopher. He believed that things needed air (or water) or some other medium to move in. So, he reasoned, that no true vacuum could exist. He was wrong about that, of course, but like so many of Aristotle’s ideas, it remained unquestioned for almost two thousand years.
Can I tell you a bit about how it was overturned because this gets at another reason to find wonder in the air around you.
Sure. That’s what we’re here for right?
Okay, imagine you’re doing the dishes. You’re standing at a sink full of warm, soapy water. A stack of dirty dishes sit on the counter, waiting to be cleaned. You grab a glass, turn it upside down and push it, mouth straight down, into the water. And something strange happens. You’ve got it so that this glass is completely under water, but there is no water IN the glass. Shouldn’t it be filling up with water? Scratching your head, you take the glass out, wad up a paper towel and jam it into the bottom of glass so that it stays there without falling out. Then you try again. Just like before, you turn the glass upside-down, put it mouth-down into the sink … but now with the wadded up paper towel inside. Then you pull the glass straight out. And the paper towel? The paper towel that was completely under water? It comes out completely dry.
Okay! This one I think I can explain. It’s because the glass is full of air and it pushes the water out of the way.
Hey! Now you’re talking like someone who believes that air is real stuff. Awesome.
But stay with me. After this, you keep washing glasses and you notice something else even weirder. You’ve got a glass submerged under water and you go to grab it and you just happen to to pull it out of the sink bottom up. And as you life it out, the upside glass remains full of water until the mouth breaks the surface at which point all the water falls out again. If you do this again, the same thing happens. In fact, if you lift the submerged glass and hold it so that the mouth of it is just under the surface, it will remain full of water, as if it were levitating.
I bet you’ve seen this kind of thing before. It’s the kind of thing we stop noticing after seeing it happen over and over for a decade or two. But take a moment to think about how weird this is. Why DOES the water stay up there? Is the glass doing something? Is there some kind of magnetism between the glass and the water? That doesn’t make sense.
I don’t know. Is it suction?
You think that maybe the glass is sucking water into itself?
Maybe?
Yeah this is a really intuitive idea. It feels simple and sensible. There’s a certain elegance to it. But it turns out that the whole idea of suction turns out to be wrong! There’s no such thing as suction.
Alright, before the cynics on reddit start arguing, I should say that there are useful ways to talk about suction. But, it really is helpful for most of us, when we’re trying to understand things like the levitating water to abandon the idea of suction.
“Wait! What?” you might be thinking. Of course, there’s suction. How else could someone drink from a straw? How does a vacuum cleaner work? What about suction cups, for chrissake? I mean, it’s even in the name!
You’re not alone for thinking this. Lots of smart people have believed in this idea–that somehow air or water can get pulled into a container or into a space or even that air can pull on something. But even in the case of suction cups, air doesn’t ever pull on anything.
Okay, smart guy. If that’s true, then what’s going on? Why does the water stay in the upside-down cup?
Well, it turns out that even though nothing is pulling air into the cup, something is pushing it. And that thing, as you might have guessed, is air.
Air is pushing all the time on everything it touches. Every wall, every tabletop, every square inch of your skin. We just don’t notice it because we are so used to it, we can’t feel it anymore.
When you are doing the dishes, air is pressing down on the counters and the dishes and … here’s the key … on the surface of the water in your dishwashing basin. And that’s why the water levitates in your glass. The glass isn’t sucking it up. The air in the room pushes down on the water in the basin, and since there’s nothing in the glass to push back on the water, the air pushes the water right up into the glass.
Take a moment to think about that. It’s weird, isn’t it … air pushing the water into the glass. It makes me wonder … is there a limit? What if the glass was taller? Or what if we had a really, really, really tall glass … like a long pipe or a tube with one sealed end? If I kept redoing this little experiment with taller and taller tubes in a giant basin of dishwater, would I eventually get to a point where the air couldn’t push the water all the way to the top? How much water could the air lift?
Turns out that scientists, being the curious people that they are, have tried this kind of thing. And time after time … experiment after experiment … the results turn out pretty much the same. Air can push water into a sealed container to a height of about 33 feet … basically to the top of a three-story building … and then … it stops.
First of all, that is one big glass of water. And second of all … why 33 feet … why not twelve or a hundred?
The first person that we know of to have figured this out was an Italian scientist in the 1500s named Evangelista Torricelli. And he realized that, if the water is being pushed into our glass or our tube by the air … and the water in my glass or in my tube weighs something … then this 33 foot limit is basically the limit of the strength of the air in the room? It’s like, “Hey, air, how much can you bench?” … 33 feet.
With a little math, you can figure out that this comes down to a whopping 15 pounds of force on every square inch. That’s about the weight of a bowling ball … on every square inch of every surface on Earth.
But, c’mon, this fact is pretty hard to believe. I can’t feel that 15 pounds. Maybe there’s been some kind of mistake.
The people of Torricelli’s time surely felt the same way. Then in the mid 1600s, a politician and scientist with a keen sense of showmanship, named Otto Von Guericke (Gare ick uh), devised a demonstration of those 15 lbs per square inch that just blew people’s minds.
Von Guericke took two big, metal bowls about as wide as your arm. He smeared grease on the lips of the bowls and fitted them together to make a big ball, a sphere. He had invented one of history’s first air pumps and then … here’s the genius part … he uses it to pump out almost all of the air inside the sphere.
Mind you, there are no latches or clasps holding these cups together. Typically, pulling them apart would be no problem. You could do it by hand. But, after Von Guericke pumped all the air out, that changed completely. Nobody was strong enough to pull the sphere apart. Even if you hooked each cup to a rope and had a tug-of-war between a bunch of burly guys … they couldn’t do it. In a famous picture of this experiment two teams of horses are pulling on the sphere, and even they couldn’t open it. To give you a sense of just how much force that is, one of those teams of horses could have pulled a schoolbus. And the only thing holding those cups together, holding that sphere together, is the air.
It was really an incredible way to show how strong that air is. Normally, if there were air on the inside of the ball, it would be pushing out with the same force as the air outside pushing it. And when that’s the case, it only takes a little bit of strength to overcome that balance and pull the cups apart. But with no air on the inside, you’d have to be able to pull against the entire strength of the outside air … a force so strong that not even a team of horses can overcome it.
So this brings us back to where we started, doesn’t it? The tanker car. Can you figure it out?
When the Mythbusters steam-cleaned the inside of the car, lots of the air inside the tanker got pushed outside. Some was displaced by the steam. Some was pushed out because air expands when it is heated. So when the door closed and the tanker was sealed, there was a lot less air inside the tanker than usual. And a lot lot less than the air outside.
I bet you can guess the rest of the story. Usually the tanker cars don’t get crushed by the outside air because the air inside the car pushes out just as hard as the outside air pushes in. But in the steam cleaned tanker car, without that balancing force … CRUNCH … 15 lbs per square inch squeezes down from every side. And the giant tanker is flattened.
Look at your hand. Right now. Look at your body. You are literally withstanding the kind of pressure that could crush a railroad tanker … Life is awesome.
How did I do? Did I convince you yet? Have I gotten you to appreciate the air around you in ways that you haven’t before? Well, don’t tune out just yet. There’s something else about air that I want to share, and I think the coolest is yet to come.
When air is pushing down on something, what exactly is doing the pushing? Imagine you had your own metal cup Von Guericke sphere and started pumping air out of it. What are you actually pumping out? When it gets right down to it, what IS air?
The answer, like everything else about air, is weird.
Air is made of individual little pieces.
Von Guericke’s pump worked by scooping up handfuls or scoopfuls of individual bits of air and tossing them outside. Inside the sphere the number of individual pieces would go down and down until, theoretically, you could have just 100 … or 20 … or 5 … or 1 … one individual piece of air.
Well, then, what’s filling up the rest of the container?
What do you mean?
Well … what’s between the air pieces?
Nothing.
Nothing?
Nothing.
What do you mean, nothing? How can there be nothing?
You’re not the first person to have trouble imagining that. I’m not sure what else to say. That space is completely empty. In fact, even when the air pieces are about as crowded as they get, they only take up about less than 0.1% of the space in a room.
Well what about oxygen?
What about it?
Isn’t there oxygen between the pieces of air?
Oxygen is actually just one type of air piece.
***
When scientists use the words air pressure, they mean it more literally than people often think. Little pieces of air art literally pressing or pushing on something. Each one with a force so tiny that no one could feel it. So small that even with a million of them all colliding at once would be easy to miss. But when you multiply that tiny force by millions of millions of millions of millions … then you can make a tire feel solid or crush a steel railroad car. It’s an absolutely astounding number of tiny collisions.
The numbers are so mind-bendingly vast. A thimble for example, one of those little metal caps that people used to wear on their fingers when they were sewing … A thimble could contain a number of air pieces in the quintillions. That’s a billion trillions. That’s more words than human beings have ever uttered in the entire history of language, that’s more gallons of water than there would be on three Earths. The point is that it’s a number so staggering that you can’t possibly imagine it–all in a container so small that a mouse could use it as a coffee mug. Imagine the uncountable quantity of them you must take in with every breath.
***
Here’s another place where it’s hard not to try and explain things with the idea of suction. But like before, you’re NOT sucking air into your lungs. Your lungs cannot pull on the little air pieces. There are no little invisible air-hooks. And you don’t push air into your lungs either. So what gives? How does air get into your lungs at all?
When you breathe, you contract this upside-down hammock of a muscle right near the bottom of your ribs. As you do, that muscle, called your diaphragm, pulls downward and expands the space inside your lungs. That’s it. All you do is make the room inside of you bigger. So why does air rush in?
Think for a moment of the air in front of your nose. It is a crowded mosh pit with sextillions of little air piece dancers. All of them are moving about … colliding … mashing into each other … pushing on each other. When that extra space opens up in your lungs, you don’t have to do a thing. That crowded group of dancers push each other into you. The atmosphere pushes itself into you. All you have to do is make room and the world itself will push into your body.
And those pieces of air don’t just stop in your lungs. They get jostled right into the cells of your body. They float around in the water stuff inside. They wander around into your blood. They dissolve into you. Spreading everywhere until you have little air pieces bumbling around in every cell … of your heart, your skin, your fingers, your legs, your bones … every living cell.
Some people think that you only breathe in oxygen. But that’s not true. Remember, you don’t control what sorts of air pieces get pushed into you. What comes in is whatever’s in front of your face. In fact, when you pull your diaphragm down, most of what your body takes in … almost 80% … are bits of nitrogen.
What does your body do with nitrogen?
What does it do? It doesn’t do anything.
So why does it take it in?
It doesn’t matter. Your body is not in control.
So what happens to it?
Well, it dissolves into you until you’re saturated with it. Until just as much nitrogen comes wandering back out of your lungs as is wandering in.
The point is that you’re taking in everything. Right now, you are breathing in pieces of air that used to be wood or gasoline but that got burned and are now little pieces of air called carbon dioxide. When your neighbor eats their breakfast, their body burns the little bagel molecules into other pieces of carbon dioxide which eventually wander out through their lungs and into the air … and they get mixed into the air and spread out. And so right now you and me … all of us … are breathing in pieces of air that used to be bagels and that used to be us. We are all breathing in little bits of each other.
And I think this is my favorite thing about air. It literally connects us all. Just like the air. I am made of pieces. And the pieces that I and you and everyone you know are made of … they all got pull out of the air by some plant. And then you ate them … or ate something that ate them … and made them into your body. All you are … all any of us are … is recycled air. And bits of you are becoming air again and I take them into me.
It makes me wonder … where do I begin? … where do you end? … when we are all made of each other. Probabilistically, your next lungful will contain an atom or two of Julius Caesar and Cleopatra, Montezuma and Cortez, Hitler and the Buddha. Saints and sinners. Artists and robber barons. Through the air, we are … literally … all one.
***
So where does that leave us? What do we take away from all of this weirdness about air? What does it matter?
We’ve spent most of this episode talking about science. But it’s worth mentioning that the Latin word for breath … the root word for both inspire and expire … is spiritus. Spirit. Etymologically speaking, breathing is the most spiritual act.
But there is another meaning of the word inspire … to fill someone with a desire or a conviction or an emotion … and, air, I think, provides this other kind of inspiration too. In his essay on humans’ capacity for wonder, John Green writes that “from the quark to the supernova, the wonders do not cease. It is our attentiveness that is in short supply, our ability and willingness to do the work that awe requires.”
It’s hard to wake up to wonder sometimes. Life is busy. There’re so many bills to pay, dreams to follow, and loved ones dying. There are things big and small to worry about and so many very important TikTok videos to watch.
And even if we do stop and take the time to ponder and to look … so many of the amazing things around us … so many wonders … are as invisible as the air. Beauty is pressing in on us from all sides. But like the incredible 15 pounds per square inch of the air on our skin, we have grown acclimated. Beauty and air pressure are the same. Of course, we can’t feel them most of the time. We were born into them. We’ve lived our whole lives in them. But also … they are real whether we see them or not.
What grace! We live in a world so wonderful. Even when we are a terrible audience to its grandeur … the sky continues to be its impossible blue, people continue to be kind to strangers, and the air does not stop holding us or connecting us, or keeping everyone you love alive.
People say that the aim of science is to explain the world. And to some extent this is true. But I think more importantly, science is there to help us to continue to wonder at things when we think we’ve got it all figured out. Sometimes it might take an imploding railroad car to remind us of it. But the bizarre beauty of air, like so many things is always there, waiting patiently for us to find joy in it. It is as close as our breath.