Does the creation of life and the theory of evolution violate the laws of thermo…

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Does the creation of life and the theory of evolution violate the laws of thermodynamics? — BY, Liverpool, NY

While the laws of thermodynamics forbid an overall increase in the order of the universe and while life is an example of significant order, the laws of thermodynamics don’t forbid some parts of the universe from becoming more orderly at the expense of other parts of the universe becoming less orderly. Living organisms are consumers of order and exporters of disorder—they derive their order by creating disorder elsewhere. You eat highly ordered chemicals in your food and you eliminate those chemicals in much more disordered forms latter on. You also emit heat, the most disordered form of energy. Thus thermodynamics has no problem with the ongoing existence of life; it simply requires that living organisms consume order and we are doing just that at a furious pace.

As for the creation of life, that could have been a random event and thermodynamics permits random events. Improbable events do occur—people win the lottery, lightning strikes twice, two snowflakes are occasionally alike—and the creation of life could have been one of those unlikely but not impossible events. Once the simplest organism had assembled itself by chance, it could then begin the process of consuming order and exporting disorder.

How hot is a match when it is ignited? Is the initial point of combustion hotter…

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How hot is a match when it is ignited? Is the initial point of combustion hotter than when it is just burning? — TB, Excelsior, MN

You can usually judge the temperature of a hot object by its color—the brighter and whiter the light, the hotter the object. A candle flame has a temperature of roughly 1700° C while an incandescent light bulb has a temperature of about 2500° C. To my eye, a struck match briefly becomes brighter and whiter than a candle flame, so I would guess that its peak temperature is somewhere in the mid 2000° C range. Once the chemicals in the head have been used up, the flame temperature drops to about 1700° C.

Why does the tower of Pisa lean?

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Why does the tower of Pisa lean? — CM, Edison, NJ

The tower was built long ago on unstable ground that was unsuitable for supporting such a tall and heavy masonry structure. For an object to remain upright indefinitely, its center of gravity must lie above its base of support and that base of support must be firm at all its edges. The tower’s base of support had at least one edge that wasn’t firm and that began to sink downward under the weight of the tower. Once this edge sunk a small distance, the tower’s center of gravity shifted sideways so that it was above that weak portion of the base of support. This shift in the tower’s center of gravity put even more stress on the weak part of the ground and caused additional sinking, additional tipping, and even more shifting of the tower’s center of gravity. This process might have toppled the tower over by now were it not for recent efforts to stop the tipping. The base of the tower has been reinforced to prevent further tipping.

What exactly are gravity waves and how are they measured?

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What exactly are gravity waves and how are they measured? — AY, Wayne, PA

Gravity waves are deformations of space/time that propagate through space at the speed of light. While many motions of matter and energy are thought to emit gravity waves, those waves are normally extraordinarily weak. The only sources of detectable gravity waves are probably collapsing and colliding stars. Careful studies of the dynamics of binary star systems have shown that they also emit reasonably strong gravity waves, but those waves haven’t been detected directly.

The two classes of gravity wave detectors currently in development or operation are large cryogenic bar detectors and laser interferometric detectors. A cryogenic bar detector tries to observe gravity waves by looking for vibrational excitations of huge metal bars. When a strong gravity wave passes through one of these bars, it should excite various vibrations in the bar that can be detected by sensitive motion sensors. A laser interferometric detector tries to observe gravity waves by looking at distance changes in the arms of a laser interferometer—a huge mirror system with laser beams bouncing back and forth within it. When a strong gravity wave passes through the mirror system, it should change the spacings of the mirrors enough to cause variations in the optical characteristics of the interferometer (for more info, see www.ligo.caltech.edu). So far, no gravity waves have been observed definitively.

How does a roller coaster work?

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How does a roller coaster work?

A roller coaster is essentially a gravity-powered train. When the chain pulls the train up the first hill, it transfers an enormous amount of energy to that train. This energy initially takes the form of gravitational potential energy—energy stored in the gravitational force between the train and the earth. But once the train begins to descend the first hill, that gravitational potential energy becomes kinetic energy—the energy of motion. The roller coaster reaches maximum speed at the bottom of the first hill, when all of its gravitational potential energy has been converted to kinetic energy. It then rushes up the second hill, slowing down and converting some of its kinetic energy back into gravitational potential energy. This conversion of energy back and forth between the two forms continues, but energy is gradually lost to friction and air resistance so that the ride becomes less and less intense until finally it comes to a stop.

Is there a device that would provide a variable output of radiated energy in the…

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Is there a device that would provide a variable output of radiated energy in the infrared that would be obtainable to experiment with? — NAT, Marion, SC

You can produce a broad range of infrared lights with a heat lamp. A heat lamp looks very dim because most of the thermal radiation it emits is in the infrared portion of the electromagnetic spectrum. Just attach the heat lamp to a normal light dimmer and you’ll be able to vary its infrared output over a wide range of intensities. Its frequency range will also shift farther away from the visible as you lower its temperature by turning down the dimmer. If it produces more visible light than you want, you can put a filter in front of it that absorbs visible light while permitting infrared light to pass. Such filters are certainly available from filter companies such as Hoya or Corning but cheaper versions (perhaps even plastic filters) may be found through scientific supply companies.

How does a computer chip work?

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How does a computer chip work? — JM, Austin, TX

A computer chip is also known as a digital integrated circuit. It is typically a thin wafer of silicon, cut from a single crystal of that element. The surface of the wafer has been chemically modified and it has had intricate patterns of aluminum wires and other structures cut and deposited photographically on its surface to form enormous numbers of transistors and other special structures. Each of these transistors is an electronically controllable switch. A tiny adjustment in the electric charge on the control element of one of these transistors—its gate—can dramatically alter that transistor’s current carrying ability. These transistors work together to perform task that range from remembering one bit of information to multiplying two huge numbers together. The millions of transistors on a typical computer chip are able to perform extremely complicated tasks, as we see everyday in modern computers.

What is the physical nature of magnetism? Is it a wave or particle phenomenon or…

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What is the physical nature of magnetism? Is it a wave or particle phenomenon or an undefined energy like gravity? — GA, Paisley, Scotland

Magnetism is one sector of the electromagnetic interactions of matter. From a classical perspective, magnetism consists of an energy-containing field that surrounds magnetic poles and that exerts forces on other magnetic poles. At a higher classical level, magnetism and magnetic fields are part of the full electromagnetic interaction, meaning that they are inextricably mixed with electricity and electric fields. Finally, from a full quantum mechanical perspective, magnetism is associated with energy-containing quantum fields, the fields of quantum electrodynamics, that govern the electric and magnetic interactions of matter. These quantum electrodynamic interactions are mediated by virtual photons, cousins of the real photons that include light and radio waves. From this quantum viewpoint, magnets interact with one another by exchanging virtual photons and, like all quantum objects, these photons are emitted and absorbed like particles but travel as waves. Thus magnetism is both a wave and particle phenomenon. It isn’t undefined at all; in fact, quantum electrodynamics is probably the most well-established and precise theory in modern physics.