Tuesday, January 24, 2012

Bad Science: Zombie Hamburgers

In today's installment of the Collapsed Wavefunction, we're going to be looking at a common myth regarding McDonald's hamburgers. I like to call it the myth of the zombie hamburger.

McDonald's: Out to get you since 1940

This myth is largely propagated through e-mail, but of course I have seen it on Facebook every now and then. It goes like this:
McDonalds hamburgers will not decompose, even if left on a counter for 12 years!!!1 If it won't decompose that must mean it is full of nasty preservatives and is obviously bad for you.
Now, I'm not about to argue that McDonald's is good for you. A Big Mac, Fries, and a Coke will give you 1400 calories, 1.4 grams of sodium, and more fat than you want to hear about. It's not a healthy choice, but not because the burgers won't decompose.

Above is the picture you'll see most of the time. We owe this little piece of pseudoscience to Karen Hanrahan, a nutritionist who bought a burger in 1996. 12 years later, that burger (picutred left) looks almost identical to a brand new burger (pictured right). It would seem that Karen has shown that something is going on with these burgers. McDonald's is clearly up to something.

Before we solve the mystery of the zombie hamburger, let's answer this question: How does mold grow on food? 

Mold needs four things to grow: Air, water, food, and a nice comfy temperature. We store our food at a good temperature for mold to grow and we keep it in dark, damp places. As you've no doubt seen, leaving food in the fridge too long is a great way to grow mold.

So why don't McDonald's hamburgers grow mold? The truth is much more boring than the tale of corporate conspiracy some may tell you. McDonald's hamburgers don't decompose because they dehydrate first.

Yup, simple as that. A dry hamburger is not enticing to mold, so it won't grow there. Try the experiment yourself. Buy two hamburgers. Place one on your counter and the other in zip-lock bag. The counter hamburger will be dry within a few hours. The zip-lock bag hamburger will retain the moisture (and, soon enough, will start growing mold). Another experiment has already been done here if you don't believe me.

If you're not quite convinced think about this. Bread will grow mold in the bag you buy it in. So why would we keep it in that bag? A slice of bread left on your counter will dry out. In 12 years it would look about the same as a slice of bread bought new from the store. It's not a bread maker conspiracy. Another example? Beef Jerky. It's dried meat that won't grow mold because it's...dried meat.

[1] Follow the link for my greatest pet peeve. The hamburger is reffered to as "chemical food." I have no idea what non-chemical food is. Plants contain chlorophyll, any meat contains proteins, and even a glass of water is a glass of (wait for it)...chemicals! 

Friday, January 20, 2012

Guest Post: Scientists - Glorified Latrine Counters

This idea has been on my mind for a while (not latrines themselves, just this analogy), so I guess it's high time I got around to actually posting it. It's based on a story from WWII, which is most likely apocryphal. However, since the metaphor doesn't rely on the veracity of the story, I'll post it anyway.

The story goes that during preparations for the invasion of Tarawa, Allied commanders were having difficulty assessing the number of Japanese troops stationed on the island. The Japanese were expert at concealing their true numbers, but they had one fatal flaw: they were too meticulous about providing adequate bathroom facilities for their troops. Allied commanders learned that the Japanese would install one latrine for every X number of troops. While the troops could easily evade recon patrols, the latrines couldn't. All the Allies needed to do was count the number of latrines on the island, multiply by X and voila! They had an accurate troop estimate.

Ok, so what does that have to do with science and scientists? Well, like the Allied commanders, we often want to quantify something that we can't directly observe. We want to know what elements make up an alloy. We want to know the concentration of lead in our drinking water. Or (and this seems to happen to me a lot) we know that we haven't synthesized what we were trying to, and we need to figure out what exactly is sitting in our flask looking suspiciously like coal tar. Unfortunately (despite what your freshman chemistry textbook may have led you to believe), we can't directly observe atoms. Let me repeat that, just to make sure you got it. NOBODY HAS EVER SEEN AN ATOM.

This begs a few questions. The first, biggest question is "How do we know that atoms are there if we can't see them?" This is a fairly involved question, with an even more involved answer, and I'm going to leave that for a later guest post (or 3). So let's just assume that we know that atoms are there, it brings us to the next question: if we can't see atoms, how do we get awesome pictures like this:
This is a stereo image of the crystal structure of the protein I work with in my lab. If you cross your eyes and align the two images, you'll get a 3D view of it.
If we can't see atoms, or molecules (even most proteins, which are HUGE by chemistry standards, are invisible even under a microscope), how can we generate such pretty pictures? The answer is indirect observation. This crystal structure was generated using X-ray crystallography. Basically, we know that X-rays diffract through matter in predictable ways (i.e. we know how many soldiers per latrine). By precipitating the protein out of solution into a crystal, and the bombarding it with X-rays and observing the resulting diffraction pattern (i.e. counting the latrines), the positions of atomic nuclei can be established (i.e. we know how many soldiers there are on the island).

Ultimately, this what any physicist, chemist, and most biologists mean when the say, "It was observed that . . . " What they really mean is that they observed a phenomenon which has been related, by theory, to whatever it is that they're studying.

There is a point, however, at which this analogy breaks down; ultimately, the Allies invaded Tarawa, and saw firsthand how many soldiers were defending the island. In science, we're never so lucky. Ultimately atoms, electrons, photons, etc. are metaphorical constructions (models), and by definition we can never directly observe them. All we get are the indirect observations which indicate the nature, number, and behavior of these invisible soldiers.

Monday, January 9, 2012

Logical fallacies: Ad hominem

One important aspect of any field of science is the ability to correctly state your position. To be considered scientific, a position must be based in reason and logic. A logical fallacy occurs when this requirement is not met. Since a clear, concise, and correct argument is important in science I am going to be highlighting a few possible logical fallacies. First up is a very common one: Ad hominem.

An argument ad hominem is an argument against a person instead of against that person's claim. There are three major types of ad hominem arguments:

Abusive ad hominem (Instead of addressing the real claim, you attack the person making the claim) 
Example: "I can't trust a word you say. You're fat and lazy"
This is a logical fallacy because being fat and lazy has nothing to do with someone's honesty.

Circumstantial ad hominem (Assuming that a claim is irrelevant because a someone is more likely to make that claim)
Example: "The dealer says my brakes need repaired, but he just said that to get more money from me"
It may be true that a slimy dealer may convince a customer to pay for unnecessary repairs. This does not mean that any repair suggested is unnecessary.

Tu quoque (You too!)
Example: "You can't tell me cigarettes cause lung cancer, you smoke two packs a day!"
A person's actions may be contrary to their claim. This does not make the claim invalid.

It is important to note that not every ad hominem argument is invalid. In some cases a person's character, intelligence, or personal beliefs are relevant to the claim. In these cases it is not considered a logical fallacy to use ad hominem arguments.
Example: "Sarah Palin seems to have no knowledge of foreign policy. She would not make a good president1." 
Also, simply attacking your opponents character, intelligence or personal beliefs is not an ad hominem logical fallacy. The attacking must be used to attempt to refute a claim your opponent has made. That being said, you can call me fat and lazy all you want - just don't say that's why you can't trust me2.

[1] I'm wondering who will argue with me because I said this.
[2] Ok...I guess if you say I'm lazy and that's why you can't trust me to do a specific task that wouldn't be a logical fallacy.

BONUS WEBCOMIC!! Check out Surviving the World by Dante Shepherd.

Friday, January 6, 2012

Bad Science in the Movies: 2012

We are entering the year 2012. The year in which, if you weren't already aware, the world is going to end. That's right, the Mayans warned us that December of this year is the end of the world.

Of course, we all know what will really happen on December 21, 2012 - millions of undergraduates around the world will panic with the realization that finals week really is going to happen (at which point they will run to facebook to complain about their dire situation).

Hollywood, however, has thankfully told us what's really really going to happen on December 21, 2012. Back in 2009 the (un)lovable John Cusack, under the talented direction of Roland Emmerich, gave us the cinematic masterpiece "2012". While I would love to criticize the plot, acting, soundtrack, and just about everything about this movie I won't. This is, after all, supposed to be a science blog so I will stick with the bad science in the movie. 

NASA calls this movie an "exceptional and extraordinary" example of bad science in Hollywood movies, and even has a website1 dedicated to correcting public misunderstandings generated by the movie. Apparently they were inundated with questions by people thinking this plot was actually plausible. 

I could chose just about any scene from this movie as an example of bad science in the movies, but I have chosen only two. The first example for bad science is arguably the most egregious example of bad movie science in all of cinematic history. The second is a bit of bad science that apparently only bothered me; I found no other mentions of it online even though I remember laughing out loud in the theater when I heard it2.

Bad Science #1 - Neutrinos

Instead of pretending I know enough about neutrinos to explain them to you, I'll let this youtube clip do the work for me:

Ok, so the important part to remember: Neutrinos interact very weakly with matter. In fact, even the largest neutrino detector can detect 0.0000000000000016% of the neutrinos that pass through it3.

In the movie 2012, the earth is coming to an end. The only scientific explanation we get is one scene in which several scientists (dubbed "WHITECOATS" in the script) discuss how neutrinos are starting to act like microwaves. Let me say that again NEUTRINOS ACTING LIKE MICROWAVES 4. So, not only do neutrinos start interacting with matter (for some unknown reason of which there is no attempt to explain) but they interact with matter enough to make this happen:

Bad Science #2 - She just can't take the pressure, captain

This next bit of bad science is subtle one. As I mentioned before, I didn't find a single mention of it online (and there are many places that list all the science faux pas found in 2012). Let me set up the scene:

Life as we know it is coming to an end. Luckily, the collective world government (based in China and commanded by American generals) has planned for such a dilemma. Inside a secret military base in China, large vessels have been prepared to save humanity. Our protagonists make their way (miraculously) to this ultra secret base and hop aboard as easily as catching the A train to JFK airport. Part of the group makes it to the bridge (because that's where passengers go, apparently) just before a massive tidal wave bombards the ship. We then hear this ominous warning from one of the officers:

"Collision pressure just below 80 Pascal, captain!"

I re-watched this part of the movie just today to make sure my memory of this hilarious line was correct - it was. It's really unclear in what context the officer meant that statement, but in any case it makes no sense. Does the collision pressure refer to the force of the water hitting against the ship or the pressure inside the ship after it had sealed to prevent  water from pouring in? Let's assume the former, since the latter would kill everyone on board5

While a barometric pressure of 80 Pascals would kill everyone inside, an officer needing to report an exterior collision of "just below 80 Pascal" is laughable. 80 Pascals is equivalent to 0.0116 pounds per square inch (PSI) - you fill your car tires with roughly 2,500 times more pressure. 80 Pascals is roughly the pressure that an adult mouse would exert by standing on the surface of the ship. This force, however, was so important that an officer had to interrupt his captain to report the problem.

To finish up, let me make one last thing clear. I enjoy this movie. It's the perfect combination of laughable science, bad acting, and liberal use of special effects. The fact remains though: it's full of bad science and many people actually bought into it. I hope you weren't one of them.6

UPDATE: If you liked this post check out one of my other Bad Science in the Movies!

[1] Also, if you're really worried, NASA has a website for tracking asteroids - just to make sure none are headed for earth a la Armageddon
[2] Ummm...I paid to see it in the theater because my wife likes these kinds of movies...ya....that's it. My wife... 
[3] This fact was calculated from information at this website, which is full of cool facts about neutrinos. 
[4] The idea of neutrinos acting like they do in 2012 makes me think of Wolfgang Pauli who is quoted as saying "That's not right. That's not even wrong". 
[5]  At the peak of Mt. Everest, the standard barometric pressure is 48,000 Pascals (not Pascal, captain). Even at this pressure, your body is unable to deliver oxygenated blood to your body - only 20% of hemoglobin in your blood is oxygenated (normal percentage would be around 98%). I don't want to imagine what it would be like below 80 pascals. 
[6] As a special treat for actually reading through the notes ( I know, I got sidetracked a lot), enjoy this "How It Should Have Ended"

Wednesday, January 4, 2012

Scientist of the Month: Carl Sagan

I approach this "Scientist of the Month" with a little trepidation. Carl Sagan isn't just some scientist of the past that I've read about in textbooks - he's the man that inspired me to become the scientist I am today. Indeed, if I had been influenced by Sagan any earlier I would be in graduate school studying astrophysics instead of chemistry.

Sagan was a brilliant research scientist. He studied the atmosphere of Venus - his thesis included the first computational model for the greenhouse effect on the planet. He also modeled the atmosphere of Mars and proposed seasonal weather patterns due to wind storms (which was later verified by unmanned spacecraft). He studied the moons of Saturn and correctly predicted liquid oceans on Titan's surface.

Carl Sagan would deserve a place in any discussion on brilliant scientists for this work alone, but he was also a tireless advocate for science and rational thinking. He wrote, narrated, and produced an amazing TV series called "Cosmos: A Personal Voyage" with the purpose of making science more accessible. If you haven't seen them, the entire series is available on Hulu. If you have seen them, here's a fun remix. He also wrote many books including "Cosmos" (to accompany the television series) and "Contact" (the book that the Jodi Foster movie is based on).

One of my favorite pictures of my son is of him reading "Cosmos". He's four years old, so he's obviously not reading the book. There's a section in the middle of the book that has pictures. My son is in love with the planets. It's a special connection we have, since we both started becoming really interested in them at about the same time. This picture is the perfect example of what Carl Sagan was always hoping to inspire: an honest curiosity about the universe.