The Oscars are coming! The Oscars are coming! And actually, the awards for technical achievement have already been made. But what about the science in the actual films? It just so happens that 2010 was a pretty decent year for slyly incorporating a smidgen of physics into the storyline. Here are Jen-Luc Piquant's picks for the 2011 Physics Oscars:
Best Depiction of Equivalence Principle: Inception.
A cognitive psychologist pal didn't care for this film because, she says, "Inception (planting an idea in someone's mind and making them think they thought of it) is actually incredibly easy." So the willing suspension of disbelief just wasn't happening for her, and probably not for lots of others with similar background. But for those of us who are keen on physics, many of the dream sequences in Inception rocked -- especially those that gave a nod to Einstein's famous equivalence principle. A quick recap: Acceleration is motion in which either an object’s speed or direction (that is, its velocity) changes. Mathematically, acceleration and gravity are equivalent, just like energy and mass. If you're riding in the elevator and someone cuts the cable, you'll go into free fall. It will feel as if you were weightless as you float inside the elevator. Since both you and the elevator are falling at the same rate, you won’t be able to feel gravity’s pull. So from your limited perspective, you might conclude (erroneously) that gravity had inexplicably disappeared. The reverse happens when you accelerate in a car: you feel a force pushing you into you seat. If you can feel gravity’s influence, you can conclude that he is accelerating. And that apparent weightlessness is what's depicted in this amazing scene -- set in an elevator, natch! -- in Inception:
Added bonus: that fight scene that takes place in a rotating hotel hallway because -- at the next level up -- the van containing the dreamers is rolling down an embankment (video embedding has been disabled but you can see the video here). That is right up there with Carrie Ann Moss trying to put out a raging fire in zero gravity in Red Planet (2000); every time she tried to use the fire extinguisher, the recoil would send her hurtling backwards until she hit the other end of the space craft. And speaking of recoil action:
Best Equal and Opposite Reaction: True Grit.
There were a couple of cool "found physics" moments in True Grit. One occurs when Rooster Cogburn makes an impressive shot from a cliff into the valley to save LeBoeuf's Texas Ranger hide: there is a slight delay from when we hear the shot (from our/Cogburn's vantage point) to when the bullet hits its mark. And a few scenes later, Mattie gets off her own rifle shot, except she's not big enough to absorb the recoil action and gets knocked backward something fierce. Rifle recoil is a classic example of conservation of momentum, also known as Newton's Third Law of Motion. If momentum is conserved, then for every action, there is an equal and opposite reaction. That is, if one object exerts a force on another for a given amount of time, the second object reacts by exerting an equal but opposite force for the same amount of time. (Rockets work on this principle, too.)
Best Scene with a Particle Accelerator: Iron Man 2.
Here we honor that pivotal scene in the home laboratory wherein Tony Stark constructs a homemade particle accelerator and uses it to create a new stable element to power the tiny fusion reactor in his chest. (I blogged extensively about this last summer.) Yes, it's technically possible to build one's own particle accelerator: all you need is a beam tube with a large vacuum, a bunch of charged particles, powerful magnets to bend the beam, and radio frequency oscillators, or RF cavities, to accelerate the particles. Sure, you could nitpick the science in this scene (and some folks did): there aren't enough RF cavities, the magnets are too small to steer the beam effectively, and Stark is apparently impervious to the massive amounts of radiation that would be produced doing such an experiment.
That said, this is, indeed, how new heavy elements have been created in particle accelerators around the world in the last couple of decades, most recently the discovery of element 117 by a team of American and Russian scientists. It's harder than it looks: those experiments produced a measly six atoms of element 117 by smashing together isotopes of calcium and a radioactive element called berkelium. And these heavy elements don't hang around very long; they decay in a matter of milliseconds. What Stark creates is something far more unique: he has discovered an element that lies within the so-called "island of stability" in the periodic table. In general the heavier the element created, the shorter its lifetime, because artificially synthesized elements are unstable and decay immediately. But with the most recent discoveries, those lifetimes appear to be lengthening once again, tantalizing physicists with the notion that perhaps there is an as-yet-undiscovered element that is both heavy and stable.
Best Nod to Conservation of Mass: TRON Legacy.
The basic premise of TRON Legacy can be summed up quite succinctly: guy gets stuck in a computer and has to fight his way out. But how to address the thorny issue of how Flynn Pere et Fils get into the computer in the first place? And how do you get them back out? If you look very carefully, you'll see a flash of light as Sam Flynn gets zapped into the game, and canisters near the apparatus, containing various elements necessary to rebuild a human body. That's there because the filmmakers wanted to at least give a nod to the time-honored principle of conservation of mass: matter just doesn’t disappear into nothingness, and energy doesn’t spring out of nowhere; energy and mass change into each other.
Einstein summed up this principle in his most famous equation, E=mc2. “E” is energy, balanced against “m” for mass, while “c2” is the exchange rate between them: the square of the speed of light. This is a very large number, which explains why a small amount of matter can produce a tremendous amount of energy, far more than a normal chemical reaction. The average human body contains roughly 1028 atoms. Once again, you could nitpick. Assuming Sam Flynn weighs roughly 180 pounds, converting most of her body mass into energy on such a short time scale would release the radiation equivalent of more than one thousand 1-megaton hydrogen bombs. This would pose a serious problem for anyone who happens to be in the vicinity during the transformation; it's amazing the arcade survived. But we'll just let that one slide, because it's just a movie -- not a documentary.
What about getting Sam out of the computer and back into the real world. Fortunately, Einstein’s equation works both ways. Energy can also convert into mass (cf. the creation of new elements in particle accelerators portrayed in Iron Man 2), although such a feat is much more difficult. Unlike nuclear decay, it doesn’t occur naturally, because it requires large amounts of energy at very high temperatures. The more mass an object has, the more energy that is required to produce it. It would take a huge influx of energy to reverse Sam’s transformation: roughly, enough wattage to power 150 million American homes for a year. If we're going to quibble further, while that equation technically allows for conversion in either direction, the exchange rate favors mass-to-energy conversions, which release heat as part of the spectrum of emitted radiation. A certain amount of the heat energy produced will dissipate and be lost. If the laws of thermodynamics are strictly followed, some small portion of Sam Flynn’s original mass should be lost forever -- hopefully nothing he'll miss!
Best Sport Physics: The Black Swan.
Okay, I admit this is really just an excuse to highlight The Black Swan, one of my favorite films from last year -- although Easy A probably takes top honors. But there's a lot of basic physics involved in ballet, like conservation of angular momentum. The way a dancer holds his or her body can affect the speed of rotation. Once in the air, a dancer controls his or her rotation speed by closing or opening the body position -- similar to how ice skaters perform their jumps and spins. A closed position, with the arms and legs pulled in tight against the body, decreases resistance and increases rotation speeds. On the other hand, an open position, in which the arms and legs are allowed to swing away from the body, causes the speed of rotation to decrease. That's why dancers tighten their body positions when performing twists or jump turns.
You could almost write a book on the physics of dance, and one person did. Physics professor Kenneth Laws has spent years studying the physics of dance, and even teaches a class on the subject, covering such topics as maintaining balance, rate of turn, "generating appropriate forces against the floor for initiating traveling movements or pirouettes, controlling the timing and height of jumps, and understanding the way dancers create illusions of accomplishing the impossible, such as the "floating illusion" in the grand jete."
So those are Jen-Luc's picks for this year's Physics Oscars. Feel free to suggest more in the comments, and not just for physics either.