The Physics of Superheroes: Spectacular Second Edition (48 page)

As manufacturing and quality-control techniques improved, and newer and smaller designs for transistors became available, another important application for this special electron valve was realized. With a small input current applied to the transistor, a small output current results. A relatively modest increase in the input current creates in turn an amplified, larger current. The output of the transistor can be either a “low current” or a “high current”; a low current is termed a “zero,” whereas if there is a high current, then this state is labeled a “one.” Minor adjustments to the inputs to a transistor can create either a one or zero for the output current. By combining literally millions of transistors in clever configurations, and making use of a branch of mathematics called Boolean logic (developed by a mathematician named George Boole more than ninety years before the transistor was invented and seventy years before Schrödinger’s equation was developed), one has the basic building block of a microcomputer.

A full discussion of how computers manipulate “ones” and “zeroes” to represent larger numbers and carry out mathematical operations through binary code would require another, separate book. The point I want to make here is that at the heart of all microcomputers and integrated circuits is the transistor. The “chips” that underlie the commercial and recreational electronics that play a larger and larger role in society, from cell phones to laptop computers to DVD players, are all simply platforms for the clever arrangement of, and connections between, a large number of transistors. The computerized and wireless technology that surrounds us in the twenty-first century would not be possible without the transistor, which in turn could not have been invented without the insights previously gained by the pioneers of quantum physics and electromagnetism.

Schrödinger was not trying to develop a CD player, or even replace the vacuum tube, when he developed his famous equation, but without his and others’ investigations into the properties of matter, the modern lifestyle we enjoy today would not be possible. All of our lives would be very different if not for the efforts of a relatively small handful of physicists studying the behavior of the natural world. With few exceptions, these scientists were driven not by a desire to create commercial devices and practical applications, but by their curiosity, which led them, as Dr. Henry Pym put it in
Tales to Astonish # 27
, to “work only on things that appeal to [their] imagination.”

25

THE COSTUMES ARE SUPER, TOO—
MATERIALS SCIENCE

THROUGHOUT OUR DISCUSSIONS of physics principles, we have been fairly liberal in dispensing “one-time miracle exceptions” to the laws of nature in order to account for a wide variety of superpowers—such as running at superspeed, altering temperature gradients in the atmosphere, or shrinking down to the size of an atom. Now we must take up one final suspension of disbelief, without which no superhero can reliably and safely use their powers. I speak, of course, about the miracle of superhero costumes!

Consider the Avengers and the Justice League of America, assemblies of superheroes in the Marvel and DC universes respectively. While the Avengers’ membership has evolved over time, typical members include Captain America, Hawkeye (the Green Arrow of Marvel comics), Giant-Man, the Wasp, Iron Man and the mighty Thor. Similarly, the roll call of the Justice League was not fixed, but often listed as members Superman, Batman, the Flash, Green Lantern, Green Arrow (the Hawkeye of the DC universe), Aquaman, the Atom, and Wonder Woman. Before the Avengers can save the world from Kang the Conqueror, the Masters of Evil, or Ultron, or before the JLA can stop such foes as Starro, Despero, or Amazo, these heroes first have to dress for success. One can’t go around avenging or forming a league for justice if one’s costume is a shredded pile of rags or a loose pile on the floor after one has changed shape and size. After all, the Comics Code Authority frowns on embarrassing “wardrobe malfunctions.”
⁷⁸

Fortunately, the question of the composition of superhero costumes that enables one to employ amazing powers and abilities—without risking an “adult warning label” on the cover of the comic book—was addressed in early issues of the first family of Marvel comics—the Fantastic Four. Recall that in the Fantastic Four, the Human Torch has a uniform that remains undamaged when he bursts into flame; the Invisible Woman’s suit turns transparent when she does; Mr. Fantastic has a jumpsuit that can stretch like rubber and return to its original shape when he resumes his normal form; and Ben Grimm, the orange, rocky, superstrong Thing, has little blue shorts.

When the Fantastic Four made their comic-book debut in November 1961, they initially wore plain civilian clothes, as they needed to fly under the radar in both the comic-book and real worlds. The quartet had to sneak onto a military base in order to surreptitiously fly a rocket ship Reed had designed in order to beat the Russians in the space race—a test flight that would lead to their exposure to superpower-granting cosmic rays. Similarly, Marvel Comics kept a low profile on the costumed-hero front when the Fantastic Four first appeared. They depended at the time upon their competitor, National Periodicals (home of Superman, Batman, and the Justice League of America) for newsstand distribution. Marvel had, up till then, published Western, young-teen hijinks, and giant-monster comics. In order to not alert National that Marvel was encroaching on their superhero turf, the Fantastic Four fought the Mole Man and alien Skrull invaders in their street clothes in their first two issues. By issue # 3 they had donned blue jumpsuits that effectively became their superhero costumes. The fashion designer to the superpowered in
The Incredibles
, Edna Mode, would probably disdain the Fantastic Four’s “hobo suits,” but their outfits are able to mimic the FF’s powers, enabling them to use their special powers without wear and tear on their clothing. How do their uniforms do it? As described in
Fantastic Four # 7
, they are composed of one of Reed Richards’ miracle inventions: “unstable molecules.” No doubt Reed has shared the formula for such an amazing fabric with his Avengers comrades.

Now, any veteran of a high-school chemistry lab class knows that unstable molecules do indeed exist. These are the molecules that that fall apart or explode—precisely because they are unstable! But is it physically possible for real clothing to alter its thermal and structural capabilities in response to the wearer’s needs? The answer is: yes! Shape-memory materials, technically known as thermoresponsive materials, “remember” their original configuration, so that after being bent or deformed, they can return to their original shape. These materials undergo a phase transition with changing temperature, pressure, or applied electric field (as in Gotham City’s crusader’s cape in the film
Batman Begins
), enabling applications from the familiar (shrink-wrap) to the exotic (surgical knots that self-tighten). Unlike melting or boiling phase transitions, these materials undergo transformations between differing crystal structures.

Before we consider designing clothing using shape-memory materials, we should ask a more basic question: What is it that determines an object’s “shape?” The properties of any solid are governed by two factors: its chemical composition and the arrangement of its atoms.

Consider carbon atoms, the super-flexible Mr. Fantastic or Elongated Man
⁷⁹
of the periodic table of the elements. Unlike most atoms, which rarely deviate from the preferred number of chemical bonds they will form with other atoms, carbon is particularly malleable in the number and type of chemical bonds it can assume. As discussed in Chapter 21, chemical bonds between atoms in molecules or solids result only when the electronic waves in the individual atoms are such that, when they overlap, “harmonics” of a sort arise that lower the total energy of the resulting bond, compared with the two separate atoms. When the bound atoms are in a lower energy configuration, we must supply external energy, such as heat or light, in order to separate them. When breaking apart a molecule, this energy is called the “binding energy.” For phase transitions, such as when liquid turns to a vapor, the heat we must provide to effect the transformation is termed the “heat of vaporization,” while before a solid melts we must add a “heat of fusion.”

Carbon achieves the greatest lowering in energy when it forms four chemical bonds, but it can do so in many different ways. It can form two strong bonds with other carbon atoms in a long line, and other types of atoms at sharp angles to the linear sequence, as in long-chain polymers such as proteins or DNA. It can form three strong bonds with other carbon atoms in a single plane, forming hexagons of carbon atoms, as we saw in fig. 38 in Chapter 23. The carbon atoms then try to form a fourth bond with the atoms in the planes above and below them. As they can form a solid bond only with either the atoms above or below, but not both, the result is very strong bonds within each plane, and rather weak ones between the planes. The planes of carbon atoms then stack into thin sheets, one atop another, like phyllo dough in delicious baklava. In this case, we call the form of carbon “graphite,” and the fact that this solid is mechanically soft, with the layers easy to peel apart, makes it ideal for pencil “lead.” Whenever you write with a pencil, you are literally unraveling a carbon crystal, layer by layer.

Alternatively, the carbon could form four strong bonds with other atoms residing at the corners of a pyramid, with the original carbon atom at its center. If the central carbon atom binds with hydrogen atoms, then we call the resulting molecule methane gas. However, if the other atoms are also carbon atoms, the resulting solid is called “diamond.” Both graphite and diamond are composed of pure carbon, but the opaque, electrically conducting and easily deformed nature of graphite results from the carbon atoms stacking in sheets, while rearranging the carbon atoms into a tetrahedral configuration produces the transparent, electrically insulating, and very hard and rigid structure of diamond.

In Chapter 15, we described how the phase of a material, whether gas, liquid, or solid, depends on the temperature and pressure. Temperature measures the average energy per atom and determines whether the atoms have enough kinetic energy to unbind into the vapor phase, for example. By squeezing on the material—that is, by increasing the pressure—we may make it harder for the atoms to vaporize, and thus a higher temperature is required to execute the phase transition. There is a balance between energy and entropy that determines at what temperature and pressure a particular material will undergo a phase transition.

Under great pressure and elevated temperatures, graphite can be transformed into diamond, as when Superman wishes to give an engagement ring to Lois Lane. Less extreme efforts are required to transform shape-memory materials from one configuration to another. Here, the phase transition involves the material shifting from one particular arrangement of atoms (called a crystalline configuration) to another. The number of atoms in the material does not change, but if the material is distorted from its previous configuration, it may require additional energy to allow the atoms to move back to their previous arrangement.

Liquid crystals are a familiar example of materials that undergo a phase transition from one crystalline configuration to another, accompanied by a variation in structural and optical properties. Liquid crystals are actually long-chain carbon molecules. Electric forces between molecules can induce them to all line up in one direction, or to self-organize into layers. The forces that lead to this ordering are weak enough that the system still flows like a liquid. The application of an external electric field can shift certain liquid crystals from one ordered configuration to another. The ability of the liquid crystal to reflect light can change dramatically depending on the arrangement of the long-chain molecules. That is, in one phase, the liquid crystal may reflect most of the light that hits it (so it will look bright), while in another phase, it will absorb light, appearing dark. Behind every liquid-crystal pixel on a flat-screen television or computer monitor are electronics, including thin film transistors, that generate a varying electric field to change the optical properties of the pixel. The procedure by which alterations on the optical properties of the pixels are translated into a moving image is the same as described in Chapter 20.