Why boiling actually is a cooling process

Science is really good at getting us to feel cognitive dissonance, or the unpleasant internal contradictions we feel when presented with information that clashes with what already know. If you swear to lay off the cookies and cakes for a whole month but break down and gorge on the third night, you’ll feel a great deal of this.  In less serious matters, the same kind of cognitive dissonance can give us a little trouble if we’re trying to understand boiling, because of our preconceptions based on what we have experienced.

Believe it or not (I hope you will at the end of this post), boiling a pot of water actually reduces the overall temperature of the water.  It’s a fairly simple mechanism, but let’s dive into it on the molecular level to see why.

When you boil water on the stove, all you’re really doing is transferring heat from the flame to the individual water molecules.  They all start to move faster and faster as they gain kinetic energy, which is related to how fast you’re moving.  Now, this whole time, you have atmospheric pressure pushing down on everything in your life.  It’s pushing down on you, your dog, all your friends and family, and even this pot of heating water.  We’re used to it, so we don’t notice pressure on us, but that pot of water definitely will.  Every time a molecule of water gets enough energy, it might go bananas and shoot out of the rest of the water, which is evaporation.  Hence, leaving an open cup of water out on a sunny summer day will leave the cup empty pretty soon — the sun gives energy to the water molecules and they shoot away, never to be seen again.

The kicker is that these molecules in heating water have to fight atmospheric pressure, and it’s a big deal for them.  Any time they try to leave the water but don’t have enough energy to overcome atmospheric pressure, they get face-punched back down into the water to roll around some more.

You know how when you tip over a glass full of ice to get the last drops of lemonade out of the bottom and then all the ice comes at you at once and attacks your nose? This is what happens when the water in the pot finally gets enough energy.  It goes out to fight with the atmospheric pressure, but this time, it’s got a couple of gym rat buddies, and together they can overcome that barrier.  That one atmosphere of pressuring pushing down on the water isn’t enough, and so the molecules fly off into the sunset (or into your kitchen).

If we take inventory of all the molecules in our pot of water, we’d reason that only the hottest molecules escape, and they escape first.  Since not every molecule gets heated to the exact same degree, the ones that get heated faster are more likely to leave the rest of the water behind sooner.  Now imagine that the top 100 hottest molecules of water all leave the pot at the same time.  Theoretically, what should happen to the temperature of the pot of water?

That’s right.  It should actually go down. When you boil something, you’re losing the molecules with the most energy first, and everything else remains.  A single molecule of water has enough energy to escape once it’s at 100 degrees celsius.  Any stragglers at 99.8 or 99.992 degrees are stuck there for a little while longer, and the overall result is that when a pot of water boils, its average temperature will decrease.

But here’s the real bombshell: you don’t need heat to make anything boil. More cognitive dissonance, right? Maybe there’s a psychology post in our future…

Basically, many people may have the wrong idea about what boiling actually means.  We tend to think it’s when you make something hot and then it bubbles, but that’s just a sign of boiling, not boiling itself.  Boiling actually means that you’ve given some molecules enough energy to overcome atmospheric pressure wherever they happen to be.  If you’re up in the mountains, there’s less air pressure overall because you’re a little bit higher up in the atmosphere.  If you were in the grand canyon, you’d have not only the pressure you’d normally have on you, but you’d also have the pressure in the vertical stretch of the canyon above your head.  You already know that water boils at a lower temperature at high elevations and vice versa, but now you know why.  It’s not the amount of heat you need to give it, but rather the energy requirement to skip town actually changes, making it easier for boiling to occur.

If you could fly to the very edge of earth’s atmosphere, you may only find that there is a thousandth of what we consider normal pressure.  At that point, you’d only need a small fraction of the energy (if you had a camping stove handy) to get your water boiling.

Finally, imagine you could make a vacuum, an area entirely free of air molecules.  If you enclosed a pot of water in a vacuum, you would find that it vigorously bubbling and boiling like it was on your stove.  In a vacuum, there’s no air, and thus no air particles pushing down on anything.  This means there’s no atmospheric pressure.  Remember our definition of boiling? Without atmospheric pressure to fight against, your water molecules will literally boil out of room temperature water.  And when you go to touch the pot after a couple of minutes, you’ll find that only the hottest molecules have left it, and the pot itself is cold to the touch.

Pretty interesting, no? Now you can fight against that cognitive dissonance while you internalize this information. The next time you go to boil water, hopefully you’ll remember that while you’re heating things up, they’re actually cooling down (because that wouldn’t cause any cognitive dissonance, right?)!

What’s the point of breathing, anyway?

No, seriously.  This isn’t some attempt to call out for help.  What is biological function of breathing? It sounds silly, but you might be hard-pressed to adequately explain just why we breathe in air many thousands of times per day.  What is it about oxygen that keeps us alive? Where does it function in our cells? What makes it so crucial? Anyone can guess that your brain needs oxygen, but if you’re satisfied by this answer, you have no sense of adventure.  In an attempt to solve this mystery, I took to the streets of Yahoo Answers, the most reputable of all internet communities.

I stumbled onto a page asking about the connection between oxygen deprivation and brain damage, or in other words, why is oxygen important?  There were some golden snippets I just had to include in our investigation:

We can make a pretty strong case for derailing any of these three explanations above:

• Response A: OK, the brain definitely need blood to flow to and from it, but does a lack of blood flow ALWAYS cause a lack of oxygen? I’m pretty sure your heart is going to be pumping a million beats per second if you suddenly find yourself suffocating in a vacuum. Sure, getting you head lopped off would defintely stop the blood flow and the oxygen by extension, but this isn’t the only way to cross off your hit-list.
• Response B: “Em let’s think….” The use of four ellipses in a row and the Cali-gurl tone immediately discredit what possible response follows the first three words.  “Maybe,” she says, “just maybe your brain survives on oxygen.” Apparently, aside from oxygen, your brain needs no other nourishment, and as we are delightfully told, we can’t survive without food.
• Response C: Not sure how I should be taking this, but if I breathe faster I can get more oxygen, and then I’ll finally grow?

Finally, Liv provided a decent response:

Thanks to Liv, we’ve determined that all cells, not just the brain, require oxygen, and we now know the reason they need it: to perform tasks. At a glance it sounds just like the responses above, but the nuance of “performing tasks” is not something that’s easily quantifed. At least Liv narrowed down the range a little bit.

Finally, this user came in and said:

One of the shortest answers on the entire page, and this user nailed it.  If we missed the mark with the previous explanation, I think we’re right on the bull’s-eye here.  Oxygen is needed to create energy in what’s called respiration.  We all studied cell respiration in high school, so I won’t bore you with details. Actually, yes I will, because it’s crucial to understanding. The easiest way to think about it that food you eat has energy that you can extract from it.  Mostly they’re “carried” in the electrons (don’t worry about this, it’s a complex topic that maybe we’ll cover later), so if you take some electrons from your hamburger and fries combo, you can put those electrons to work for you.  Usually, you make ATP with the electrons, since ATP can be stored and used for whenever you need it, whether in a few minutes or a few hours.  So where does oxygen fit into this whole “use stolen electrons for energy” thing?

Where you find oxygen in your cells. Thanks, Wikipedia!

Notice, circled in red, the glorious molecular oxygen standing by.  What we’re looking at here is the inside of one of the many components of your cell. This one’s a mitochondria, which you may remember as being the only organelle that anybody who took Biology remembers.  The space that contains oxygen is the matrix (glad we finally know what that is, thanks Keanu Reeves!), which would be like the inside of your liver, or something weird.

Those big blue ovals that are sort of “built into” the membrane there are electron carriers.  When you steal those electrons from ice cream and kettle corn, they find themselves inside the mitochondria, where they end up being passed off to those big blue ovals.  Each oval then sequentially steals the electrons from the oval before it, and a little bit of the energy from the electrons gets released between each successive thieving. They’re proteins, in case you’re wondering, and together they’re the Electron Transport Chain.

Once the electrons get to the end of the line, they’re plum out of energy, so we can just throw ’em away and grab a bunch of new electrons.  Now imagine you just spent an hour grocery shopping and your shopping cart is overflowing with delicious electrons.  As you step up to the only open cash register, the cashier turns off the light and closes the lane.  This is sort of what happens as electrons get to the end of this transporting chain.  They reach the end and sort of go “well, now what?”  This is where oxygen comes in: it says “Oh, oh! My lane’s open, come on down!” and electrons are like, “Aw yiss!”

Oh, one more thing.  When electrons travel, they usually wear a hydrogen suit, and the two are frequently inseparable.  So that whole time we were moving electrons, we were moving the remains of the hydrogens they came from, which is really just a single proton (since hydrogen has a single proton and a single electron to begin with).  To make a long story short, those electrons turn that turbine up there in the left-hand corner (yes, it’s a functioning machine) and the energy from the turn get transferred to ATP. Now we’ve got all these hydrogens, electrons, and oxygens meeting up in the same place, maybe in the parking lot of the grocery store in our analogy.  They decide they really like each other, and go out on a date immediately for some strange reason.  Anyway, the result is good old water, which is why when we breathe, we produce water.

Oxygen typically wants to bond with exactly 2 other things at a time. What was the formula for water again?

So, we need oxygen to remove old and broken electrons, and to bond with hydrogen to form water.  We also release carbon dioxide in our breath, which is how you know you’re alive (no other methods are currently thought to exist). No oxygen, no energy formation. No energy formation, no energy.  No energy, you are by definition dead.  Now we can start to think about the widespread consequences this has on our bodies.  Brain damage can be caused by a few minutes without oxygen because the brain is a hungry, hungry hippo — it’s gonna stop working if its cells aren’t constantly making, using, and releasing energy.

So why is oxygen seemingly the only molecule capable of eloping with hydrogen to form water? It’s not the only one, but it seems to be the most effective at what it does.  Oxygen loves to grab electrons out of the air if it finds them (think fat kid finding an ice cream bar on the sidewalk, still frozen), and it does this better than most other common substances.

But that’s a discussion for another day (as long as I keep on feeding my brain tasty, taste oxygen.).

Next time: You’re telling me that boiling something actually makes it colder?

Trust me, Soap is a Modern Marvel

A lot of the topics I want to cover in this blog frequently arise from the most mundane of thoughts.  This one in particular, the mechanism of action of soap, is actually fairly sophisticated and quite interesting.  It’s not going to win anyone over and your next party, but it might make you a little more grateful for the sudsy buddies we call hand soaps.

Most molecules in nature are either polar or non-polar, which basically means they can either attract or repel water.  You know that oil sits on top of water, but you might not known it’s because the water molecules, each attracted to each other, can literally push out the non-polar oil molecules and leave them hanging out all alone.  By shaking oil and water together, you can just barely get them to mix, but let it settle and you’ll see they’ve separated once again. If you mix egg yolks and vinegar and shake them hard enough (or blend them), you’d make mayonnaise!

In reality, many molecules both natural and man-made can have areas where they are polar and non-polar — they can attract water and oil.  So if you put one of these amphipathic (fancy word, but it just means a molecule has regions of polarity and non-polarity) molecule in some salad dressing, it’s likely to grab on to a little bit of everything.  To illustrate this point and relate it to our topic at hand (see what I did there?), let’s quickly look at a single soap molecule.

Notice how the molecule has a blue part and an orange part.  The blue part is attracted to water — in other words, if you put the blue part into water, it would dissolve.  The orange part is non-polar, or not attracted to water.  That’s the “oil” component of soap.  Soap therefore can both dissolve and not dissolve when put in water.

In a handful of soap, the heads (the green parts, like the blue part above) will want to interact with water, so they will face outwards.  Since the tails don’t really feel like touching water, they’ll tend to be pushed inward so that they can form their own club for non-polar things.  This circular arrangement is called a micelle, but that’s not super important.  Just realize that soap molecules will naturally make these little circles all on their own because one half of each molecule will tend to look for and bond to water.

Say you spill a little olive oil on your hand.  When you go to wash it off with plain water, the oil can’t be dissolved in water, and the water will simply run off of it.  Your hand won’t be clean and that’s a bummer.  If you use soap, though, and your run your hands under water before washing them, the soap molecules will form the circular shape to the left to try to get to the water.  The olive oil will be sought out by the tails of these molecules, and droplets of oil will become trapped within these spheres.  The tails of each soap molecule bond to the oil droplet and keep it enclosed within the sphere.  And thanks to the water-seeking heads, these molecules go with the water when it enters your drain, and out of your life forever.

After you wash everything polar and non-polar off of your hands, there’s hardly any dirt left.  The market, however, has taken a liking to a chemical called triclosan, which actively kills bacteria on your hands as opposed to just washing them away.  Thanks to the properties of natural selection, it is possible that we are quickly breeding triclosan-resistant bacteria, so that some day in the future, we’ll need to find another anti-bacterial agent.  Resistant bacteria and residual triclosan have already been found in waste products , so I expect the research to breakthrough to either side in the near future.

Interestingly enough, the molecule above are very similar to the ones our cells use as their first line of defense: the plasma membrane. It’s difficult to get all but a few types of substances into the cell unless the cell wants it, because most molecules can’t cross both a polar and non-polar barrier.   And now we’re taking that evolutionary tactic and getting the gunk off our hands! Hah!

Explain Like I’m Five: Entropy

Retrieved from http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/01/entropy.gif

It’s a frequently misunderstood concept, but at its core, entropy is very, very simple.  So simple, in fact, that you could explain it to your five year old son or daughter.  Let’s see what that would sound like.

“Son/daughter, you know that I always tell you to clean your room and keep it clean.  Every time you play a board game, get into bed, or get dressed, the room gets a tiny bit messier.  You put your dirty clothes in a pile on the other side of the room, the sheets are all messy and the bed’s not made.  Wouldn’t it be great if you never had to clean your room?

Messiness is everywhere, and the reason why things become messy over time is because there are many ways to have a messy room.  Your clothes might be all the place.  Maybe you left the toys out, and maybe the DVDs and Blu-rays are scattered all over the floor in front of the TV.  But you know, there’s only one way to make a room not messy: the toys need to be put in their boxes, the movies need to go on the shelf, and the clothes need to get folder and put into the dresser.  There are a bunch of places in this room where your dirty shirts could go, but only one place where they are kept when they are clean.  There are a hundred places in this room where the movies could go, but the only place they belong is on the shelf with the other movies.

Messiness is also called entropy, but you don’t have to call it that.  If you think of every possible version of your room — the versions where the room’s neat, the versions where everything’s messy — you’ll see that there are millions and millions of ways that your room can be messy, and only a few ways it can be clean.  So outside in the big world, things usually get messier and messier because it’s the natural way for things to be.  Could you break an egg into a pot and then put it back together inside its shell?  No way!  What if you dumped out all your action figures at once — do you think they land in a messy pile or that they would all land neat and order lined up in rows?

So that’s entropy, son/daughter.  It just means that the entire universe gets messier and messier as time goes by because the chances of anything being messy are way higher than the chances of that same thing being orderly and clean.”

Now for the “explain like I’m twenty-five”: Entropy is an inherent property of matter due to the nearly-infinite possibility of microstates that can exist for any system (a system being a toy, a car, the world, the universe, etc.).  If you counted all the microstates of the universe, 99.9999% repeating of them would be largely disordered.  You’d be lucky to view the universe’s microstates for a million years and come across one that is orderly.  It takes energy to combat entropy. Entropy occurs naturally, so in order to un-clutter a system, the system needs to have work done it in the form of energy.  By walking down alleys and roads and picking trash, you’re expending a lot of energy, with the result that your town or city is slightly more ordered than it was before.  Entropy is measured in kilojoules per kelvin, which is a fancy way to say “Work per temperature degree.”

There’s quite a bit more to entropy, including the loss of energy in the form of heat with every piece of work done, the maximum efficiency of any engine based on thermodynamic limits, and the eventual heat death of the universe (where all energy is finally spread out uniformly in space and we can’t use it to produce useful work anymore).

Depression or a Migraine? Would You Rather…

As a brief followup to our earlier discussion on the different “versions” of biological molecules, let’s take a look at a particularly poignant example of the power of enantiomers.

McMurry, J. Organic Chemistry, 8th Ed. pp 171.

Let’s break this down into something that’s easy to understand.

The molecule you see above, fluoxetine, is prescribed nationally for depression. It boasts one of the highest prescription rates of any medication available.  The term chiral above means that if you were to find a bicycle-sized model of the above molecule, you could put it in front of a mirror and its mirror image would not be the same.  The most common comparison is of your left and right hands — no matter how you do it, you can’t superimpose either of your hands on the other and make them exactly the same.  And, like your left and right hands, the two “versions” of the drug above occur in equal proportions throughout nature (or at least in a laboratory).  The term racemic activity in the picture above means that when you get fluoxetine from your pharmacist, it consists of equal parts “version 1” and “version 2” of fluoxetine.  Each version has wildly different strengths and effect on your body, but scientists just sort of throw it all in there and hope for the best.

The version you see above is used for treating migraines, but has no anti-depressant effect.  The other common version of this molecule, however, does nothing for headaches, yet works well at fighting depression.  How could a simple mirror imaging of this molecule give its two versions such different properties?

Retrieved from http://scientopia.org/img-archive/scicurious/img_108.gif

For one thing, most anti-depressants including the one above (it goes by Prozac) function by preventing the recycling of free seratonin in the brain.  When your brain cells want to communicate, they can send seratonin out to other cells to get a message to them.  The drug works by slowing the recycling of seratonin so that more of it can reach the receiving cell at a time.  On the other hand, the drug in the picture above is 20 times more effective at preventing seratonin recycling in the brain, but for some crazy reason only helps with headaches, and the jury’s still out on the true efficacy of the drug.  The killer is that we still don’t know how Prozac works — it’s part of a class of drugs that follow the “shoot first, ask questions later” philosphy.  Scientists knew that they wanted to prevent seratonin recycling, but they weren’t sure how to do it. They set off to design a molecule that could do it and do it well.

In other words, they know that Prozac does what it says it does because that’s how they invented it. If chocolate cured obesity by forcing fat to be preferentially burned, you can bet that scientists would be using what’s called rational drug design to try to create a molecule that forces your body mimic that effect.  The advantage is that a synthesized molecule can be far more effective than a naturally-occuring one (St. John’s Wort is a naturally-occuring and common, but compared to Prozac, it is a relatively weak anti-depressant).

The whole “fitting molecules into receptors” thing really comes into play here, but this is a special case because we literally don’t know what this stuff does.  All we know is that it works.

Now where can I get my hands on some of that fat-burning chocolate?

Flappy Bird Physics

All us kids these days are playing this game called Flappy Bird, where the goal is to die repeatedly while screaming at the top of your lungs about how hard it is.

Funny thing about science though, is that we’ve worked out a lot about the motion of objects; if we have just a little information on our object, we can accurately determine an object’s acceleration, velocity, and distance traveled. Basically, we can use math to make predictions about what will happen as the object moves.  If, for example, we want to inspect the flight patterns of a certain infamous bird, we can apply some simple science and make accurate quantitative predictions concerning its motion. In short, any moving object can have its motion fully described if 3 of the 5 following factors are known:

• Starting velocity
• Current velocity
• Acceleration
• Distance traveled
• Time taken to travel that distance

I hate math, so let’s keep this one easy-to-read, OK? We’ll start by determining what kind of bird Flappy Bird actually is; this will come into play later.  We assume that Flappy Bird is flying through his pipes somewhere here on good old Earth, but we’ll keep an open mind when we look at the effect of gravity.  Could F.B. be on Mars? Who knows? After we figure out its species, we’ll look at its motion, attempt to define its values for the five variables above, and see if we can’t learn a thing or two about the relative accuracy of Flappy Bird’s flight patterns.

First, consider the species of the Flappy Bird.  A Google search reveals there are about 400 species of birds native just to Hanoi, Vietnam, where the game’s creator resides, so we’ve got our work cut out for us. It’s safe to assume Flappy Bird was envisioned based off creator  Nguyễn Hà Đông‘s personal experiences with birds, so we’ll start in Southeast Asia to see if we can find a close match. We’ll start with 3 potential species:

Black-naped Oriole

Common Iora

Baya Weaver. Cute!

Note that the species here were sighted in Singapore, which is just a hop, skip, and jump across the ocean from the southern tip of Vietnam.  Of the three, the first one, the Black-naped Oriole, looks like the closest match, although the Baya Weaver is also a candidate. As for size, we’re probably looking at a range in size from 23cm to 27cm. If we take a look at Flappy himself, we can stack him up to try to determine the size of his playing field.

How far is Flappy from the ground? MS Paint will show us the way!

If we assume the bird’s size to be about 25 cm, we can see that about seven and a half flappy birds reach all the way to the ground below him. This is about 187 cm, or about 73.6 inches, OR about 6.1 feet. From the ground, his distance traveled in meters would be 1.87 meters. If Flappy Bird falls from this height, my stopwatch calculations indicate about .7 seconds. So it takes our bird less than one second to fall 1.87 meters. So far, so good.

We know that when Flappy Bird begins to fall, his initial velocity will be zero at his peak height.  This is because the force of gravity stops his upward acceleration and begins to drag him downward.  At the moment that gravity becomes the predominant force (his flapping has ceased), he is instantaneously at rest in the air. We can set initial velocity to zero meters per second, and use our values for distance traveled and time to figure out the rest. In summary,

• Velocity₀ = 0 m/s
• Time = .7 s
• Distance traveled = 1.87 m.
• Acceleration = ???
• Final velocity = ???

A kinematic equation relation distance, velocity, and time.

A first-semester physics course teaches you that there are 5 “kinematic equations” that can fully describe the motion of a one- or two-dimensional moving object.  Of these, the one we can used based on the information we have and the information we need is the one just up above, where x represents distance, v represents velocity, and t is time. The subscript of zero indicates this is the starting value, and the variables without subscripts are used to represent the final values for distance and velocity, respectively.  Notice that we’re missing only one variable in this equation, which means we can fill in the rest of the numbers and solve for the missing one.  Let’s do that now.

Essentially, we’re being told here that Flappy Bird starts at the apex of his flight at a velocity of zero and an arbitrary positioning of zero.  We can take downward to be the positive direction and find that his velocity is about five meters per second.  Note that the weight of a moving object has no bearing on its motion when the only force at work is gravity.  As Flappy Bird stops flapping his wings, the only force acting on him is the earth’s gravitational force, which pulls him downward faster and faster. If he were a little higher off the ground, his ending velocity would have increased not only linearly with respect to his distance from the ground, but by orders of magnitude as the force of gravity forces his velocity to increase at a rate of 32 feet per second per second, or 9.8 meters per second per second.  This is, of course, assuming we’re on planet earth here.

 In general, motion that involves both up-and-down and left-to-right motion can be broken down into these two components, which can then be analyzed individually before being reassembled to produce a cohesive description of motion.

Original image from http://images.eurogamer.net/2014/usgamer/FlappyBird.jpeg

Finally, we can plug in this data to find out the acceleration of our poor bird and figure out just where in the universe he might be.  Here’s the logic behind it: We solve another of the 5 kinematic equations to figure out Flappy Bird’s velocity, then match our value against the known values of gravitational acceleration for planet earth.  If the values don’t mesh, we’ll try to find an alternate planet for Flappy Bird to live on that more closely matches the physics of his surroundings.

Our next kinematic equation is as follows:

Note that by using 4 of the 5 variables in the equation, we can force the equation to solve for acceleration.

We already know everything except acceleration, so it’s a simple plug-and-chug exercise.

Let’s solve it just like we did the one earlier:

Relative gravitational forces of planets in our solar system.

Within reason, we can determine that the gravitation acceleration on Flappy Bird’s home planet is less than that of planet earth.  If we divide his acceleration by earth’s acceleration, we see that his acceleration due to gravity is about 77.9% of that on earth.  So where in the universe would something fall with about four-fifths the acceleration of that found on earth?  Let’s start within our solar system by checking out the gravity of each planet  As this nifty chart shows us, there are seven celestial bodies within our solar system with surface gravity less than that of earth’s. Both Uranus and Venus are a closer fit, but even they’re a little too high at 8.87 m/s/s. If we had to choose one planet, we would say that Flappy Bird probably lives on Venus, noting that our calculations have a roughly 15% margin of error.

But what if Flappy Bird isn’t actually on a planet in our solar system?  If we assume that his native planet is indeed earth (given his phenotypic similarity to the three species mentioned earlier), then perhaps he’s in an orbiting body. We tend to think of earth’s gravity of having a magnitude 9.8 meters per second squared. However, the farther you move from earth’s center, the lower the gravitational attraction becomes.  This is because as two objects get closer, their attraction for each other increases exponentially. Similarly, a separation between two objects cuts the gravitational attraction dramatically.  So if you’re twice as far away from the earth’s center, the change in attraction isn’t merely just half the value — it’s a quarter of the original gravitational force.

The astronauts up in space still feel earth’s gravity pulling them inward, albeit at a lower magnitude.  When an astronaut in a space station is orbiting earth, he’s moving so fast in a circular motion that earth’s attraction can’t pull him straight back down — instead, the orbiting object uses the earth’s gravitational attraction to fling itself around earth over and over, and since it’s moving so fast than it keeps on circling the planet instead of falling down towards it, it stays in constant orbit.  This is why it’s incorrect to say “there’s no gravity in space.” In fact, there is still a relatively strong gravitational force, but every time the earth tries to pull an object inward, that object just keeps barely missing earth and ends up circling around it almost indefinitely (thanks to the near vacuum of space, there’s no air resistance to slow a satellite down).

As a final experiment, if we assume that Flappy Bird is inside of a fancy space station orbiting earth, we can use what we already know to figure out just how far away he is.  We can use an equation called The Universal Law of Gravitation. The math is all done in the box to the right, and we can see that Flappy Bird is about 7230 kilometers away from the surface of the earth.  This means that relative to us, he’s 859 km higher up in the air, away from earth’s center.

If we consider an object with an orbital period the same as earth’s (meaning that it makes the same number of revolutions that earth does in the same amount of time, so it’s always in the same place in the sky), we would need to be exactly 35,786 kilometers, or 22,236 miles away. We’re nowhere near that far, so Flappy Bird must be fairly close to the earth.  For reference, while a satellite may be 22,000 miles away, the moon is 240,000 miles away. Yikes.

So there we are. We have fully described Flappy Bird’s motion using physics. We know that his acceleration towards whatever he’s above is a little bit less than earth’s, and we figured out how far he would theoretically be from earth, were he a bird native to our planet.  I was surprised that our calculated acceleration was reasonably close to that of earth’s, given the “drop like a rock” style of the game that makes it so frustrating (and so addicting!). Just goes to show you that even in the depths of the largely mediocre free-to-play market, you can always pull out a little bit fun.

A visual guide to other potential matches can be found courtesy of http://photo.birdwatchingvietnam.net/ The potential species match photos are cited from here, here, and here, and all credit goes to the original author and bird photographer of those web pages. Other images cited include:

•  http://upload.wikimedia.org/wikipedia/en/d/db/Flappy_Bird_logo.jpg
• http://s.pro-gmedia.com/videogamer/media/images/pub/large/flappy_bird.jpg
• http://images.eurogamer.net/2014/usgamer/FlappyBird.jpeg
• http://www.enchantedlearning.com/pgifs/Planetgravity.GIF

Side effects

Ever taken a prescription drug and had a nasty side effect? Ever done heroin and fallen out? Ever taken 13 oxycodone at once and felt just a tad unusual? I sure hope not.

Most drugs occur in descrete molecules of the active ingredient.  The active ingredient in Ritalin, for example, is something called methylfenidate. That means when you swallow that pill, you’re swallowing a whole bunch of molecules of methylfenidate and letting them do their thing.  The thing that they do, of course, provides the active effect of whatever therapeutic drug it is.  Side effects of Ritalin and other ADHD medications include dry mouth, loss of appetite, and nausea.  So what’s with those side effects?

Part of it, of course, it just how well your body responds to such drugs.  Your body is constantly trying to keep itself in a homeostatic environment — all that means is that if it’s cold outside, your body makes you shiver so you return to your normal temperature.  If you drink too much coffee, your body will release chemicals that try to slow down your heart rate and blood pressure.  Anything you do is probably going to result in an imbalance in your body’s activity, so you’re kind a jerk, aren’t you?

Another big part of why drugs give us side effects is the result of the behavior of molecules.  You may have heard that the meth you can buy on the street and the ephedrine you can buy at CVS are actually the same compound — that’s sort of true.  They share similar formulas and structural bonds, and both are similar to adrenaline in the way they affect your body.  So why is meth illegal, and yet ephedrine is freely available? Actually, ephedrine can be easily reacted to make meth, but unless you’re an expert chemist, I can’t recommend it (for several obvious reasons).  Notice how similar their chemical structures are – and yet they produce wildly different effects on your body.

A lot of the time, an organic molecule (one with carbon and hydrogen) can come in different “flavors” called isomers.  Specifically, a stereoisomer comes in at least 2 flavors, each having the same chemical formula. The only difference is in the orientation of its atoms.  You may have heard of a term called “chirality” on Breaking Bad that refers to 2 stereoisomers being mirror images of each other.  In other words, if you have some configuration of a molecule, you can have a different configuration that is its exact mirror opposite.  Since all the chemicals you take in fit into receptors within your body, you might imagine how one molecule can fit into a receptor, while its enantiomer (the other version of the molecule) may not quite “fit.” Thus, if you take methamphetamine, its 3-D structure is such that it binds to the receptors you normally use for adrenaline.  Ephedrine, chemically similar but with a slightly different orientation, can produce no such effects.

One way of telling the difference between isomers of the same molecule is by using D- and L- notation, which is related to the way each version responds to polarized light.  For example, in the medication Adderall, there is present only the D isomer of amphetamine saccharate — its sister L-configuration is nowhere to be found.  Why?  Perhaps that version is completely unreactive and doesn’t produce any result in a patient’s body.  Perhaps that version causes massive internal bleeding and hallucinations.  Perhaps it’s more effective but way more difficult to synthesize.  So sometimes only one version of a substance can work because its other configurations don’t fit into receptors, produce poor results, or can do more harm than good. To be more accurate when looking at “versions,” we can use R and S notation, which means that we look at the bonds within the molecule and use a man-made method to differentiate between them.  Since D- and L- notation refers to polarized light, S and R notation is probably more accurate when you need to tell your friend about a specific version of a molecule.

Anyway, this all leads to a point: drug manufacturers are good at what they do, but not even the best chemist in the world can remove every single isomer of a drug before it goes to market.  If a chemist wants only the D version of some substance, there’s a good chance he’ll generate some L configuration of that same substance during the synthesis.  So when you take a substance, you’re quite possibly taking the wrong configuration along with the good one. This alone has the potential to produce some of the negative side effects of drugs.

Let’s also account for the specificity of a drug. When you take a pain reliever, what you really want is for your headache to go away. But that Tylenol can’t tell your brain from your legs; it just does its chemical thing, binding to receptors that sense pain and helping you get on with your life.  The problem is that if other parts of your body have the same receptor, the drug can produce unwanted effects.  Another good example is cold or allergy medicine — it makes you tired because the receptors is binds to are also tied to sleepiness – since you can’t force the drug to work only on the correct receptors, it’ll jam itself into any receptor that even sort of looks its way, activating all kinds of other imbalances in your body.

As a final example, consider a lactose-intolerant person drinking a gallon of milk.  A side effect might be nausea, but here the reason is a little more clear-cut: everyone who is NOT lactose-intolerant has a chemical in their body that can break apart lactose, which is the main component of milk.  Thanks to evolution, not everyone will have this chemical’s coding  in their DNA sequence, meaning it can’t be synthesized natively. So when they go to take a drink of milk, their body just has to deal with it and start passing the un-broken down lactose through your digestive tract.  Problem, though.  The little bacteria that live in your gut DO have a means to break apart that lactose and use it for their own purposes.  They eat it and release gases as a result of metabolism – so while you don’t get any energy from drinking lactose, your GI tract is having a great time. You’re stuck feeling bloaty, sick, and dishing out massive fartbombs of sulfurous gas, all because you forgot to include that breakdown chemical back when you left the womb – so sorry.

So there we are: we know that substances can have side effects as a result of an inability to target specific receptors, an inability to separate isomers from each other, or an inability to be broken down and then used by the body.  Keep in mind that even oxygen is psychoactive, meaning it crosses the barrier to the brain and acts to produce some effect. Now imagine any one of the millions of chemicals you eat, drink, or otherwise consume, and it’s a miracle of science we’re all still here.

Thank homeostasis. That guy’s on the ball.

Empty Space

Why aren’t you falling through the floor?

I said, why aren’t you falling through the floor?  You might be sitting on a couch, your office chair, or your car seat (please don’t blog and drive).  But if you take a close look at the atoms that make up the universe, you start to realize the dubiousness of the solid objects we take for granted.  To get to the heart of the matter, we’ll take a look at atomic structure, what makes it amazing, and why that makes you amazing simply for existing.

An atom has protons, neutrons, and electrons. Any element — whether hydrogen or uranium — uses this same atomic structure.  Neutrons and protons are packed densely into the center of the atom, while electrons fly around the outside like drunk drivers.  Electrons have a mass about 2,000 times smaller than the protons and neutrons, and those guys are already pretty small already:

This leads to a new measurement of the electric charge radius of the proton. Its value of 0.84087(39) femtometres (1 fm = 0.000 000 000 000 001 metre) is in good agreement with the one published in 2010, but 1.7 times as precise.

Read more at: http://phys.org/news/2013-01-physicists-surprisingly-small-proton-radius.html#jCp

So any proton has a radius of about 1 femtometer.  A femtometer is roughly 10^-15 meters, or .000 000 000 000 001 times the length of a meter.  In other words, invisible to eyes and microscopes alike.  Likewise, the mass (or weight, if you want think of it that way) of a proton or neutron is about 1.67262178 × 10^-27 kilograms, or 3.5274 x 10^-22 pounds.  Yikes.

It’s hard to conceptualize the size of sub-atomic particles, so let’s say that if a single hydrogen atom took up the space of the room you’re sitting in, the nucleus housing the protons and neutrons would be the size of a single grain of rice.  The rest of that sphere of an atom is empty space, save for the electrons.  Most atoms fall within the range of 0 to 100 electrons; hydrogen has none, while Neon has 10 electrons.  Electrons spin in shells around the nucleus.  Anywhere they aren’t spinning, there’s literally nothing but empty space.

Consider the size of the average coffee table.  Your average coffee table is about 30 pounds of mass, and if it’s made of wood, it more than likely has a great deal of cellulose as its primary material.  A single molecule of cellulose has the formula (C6H10O5)n, where n means the number of these molecules all linked together in a single long chain.  Those monomers form a polymer of cellulose, which makes up the basic structural material of trees and plants.

We can find the weight of a single cellulose molecule here.  I’ll skip units for now and come back to it next for ease of understanding.  Each carbon is 12, each hydrogen is 1, and each oxygen is 16.  We have 6 carbon atoms, so 6 X 12 = 72.  We have 10 hydrogens, so 10 * 1 = 10. Finally, 16 * 5 gives us out value for oxygen, which is 80.  Adding up these 3 values, we get 80 + 10 + 72 = 162.

But 162 of what? What exactly are counting here?

There are 2 answers, and we’ll keep it short and sweet here.  It could be 162 atomic mass units, which is sort of like a pound for your little protons and neutrons. If you could weigh an atom, that’s about the value you’d get.  We could also be talking about the atom’s molar mass; a specific huge number of cellulose molecules would weigh 162 grams. Yes, we’re talking about moles here.

A dozen eggs is 12 eggs.  A baker’s dozen is thirteen. A mole is 6.02 X 10^23.  That’s the number of “things” in a mole.  So if we have a mole’s worth of atoms, then we have 6.02 X 10^23 atoms. And because of the way moles are defined, a mole’s worth of any element is the same number in either atomic mass units or grams. In other words, there are 162 atomic mass units in each cellulose monomer, and there are  602 000 000 000 000 000 000 000 cellulose molecules in a mole’s worth of cellulose. Each time you weigh 162 grams of cellulose, you’ve weighed exactly a mole’s worth of cellulose.  For reference, this mole number is larger than the number of stars in the universe.

Now for the fun part. Let’s convert our coffee table’s weight to kilograms and see just how many cellulose molecules are in it.  31 pounds is roughly 14 kilograms, and if each mole weighs 162 grams, we should divide 14,000 grams by 162 grams.  Your table has 86.41 moles of cellulose within it that make it what it is.  Maybe now you can sort of imagine how tiny these guys really are? To really blow your gasket, let’s see how many individual cellulose molecules make up that table: it’s 86.41 moles, so that’s 86.41 multiplied by 6.02 X 10^23, or about 5.2 X 10^25 discrete units of cellulose.  I know, at this point, numbers become meaningless, but try visualizing in your head the orders of magnitude of such a number: the ones place, the tens place, the hundreds, the thousands, the ten thousands, the hundred thousands, etc. See how far you can get.

Any atom is mostly empty space — maybe 99% empty space or so. Electrons are so small they essentially don’t have a mass.  That means your coffee table, though it may look solid and hold your hot coffee, is 99% empty space. Nada. Nothing. Absolutely nothing.  The water you’re drinking? Its hydrogens and oxygens are mostly empty space, bound together in molecules of H2O. You? Well, you’re mostly water anyway, so you’re already at a disadvantage, but even your solid parts (organs, tissues, your brain) are 99% empty space too.  How can anything that almost nothing at all be solid, or even observable?

The truth is electrons and protons carry charges (I’m sure you remember this – electrons have a negative charge).  Like charges repel. When you stand up to go get more coffee, you’re not actually standing on anything – the charges on your body are repelling the charges of the floor. You’re essentially floating on repulsive electric charges while you eat, sleep, sit in your favorite office chair, or drive your car.  Think about that outermost layer of your skin that wants to make contact with that outermost layer of the fabric of your comfy bed — those electrons don’t like each other, and their repulsion is subsequently the only driving force that makes you think you’re sitting on something.

Ever try to push a car when it won’t start? You’re really pushing nothing but empty space, thin air, and yet, the electrostatic repulsion from your hands and the car make the car feel really heavy. The combined weight of all the molecules in that car make it extremely difficult to get it moving — your poor electrons can only do so much!

What would happen if we removed all electric charges from the world? Would we suddenly fall into a pile of unidentifiable matter? Would we sink into our chairs and become one with the universe? Would you fall into the floor every time you took a step?  It’s not exactly a fantasy. The universe is 99% empty space already, and everything that has a mass is 99% empty space yet again.

So why aren’t you falling through the floor right now?