This week’s question was asked by a friend.

QUESTION: What is quantum physics?

ANSWER: Quantum physics or quantum mechanics is a branch of science that deals with how nature behaves at the atomic level or area of the infinitesimal.

The foundations of quantum mechanics were established in the first 40 years of the 20th century from about 1895 to 1935. The big names in this field are Niels Bohr, Max Planck, Albert Einstein, Werner Heisenberg, Louis de Broglie and Erwin Schrodinger. There are a host of minor players.

Max Planck stated that energy is radiated or absorbed into discrete bundles or “quanta, and that energy is related to the frequency (number of vibrations per second).

He was clever enough to come up with a formula that says so: E (energy) equals h (Planck’s Constant) times f (frequency). (E = h f )

We can kind of see quantum mechanics at work in everyday life. Heat up a piece of iron, say a horseshoe. The first color of the glow given off is red. Keep on heating it and soon it turns orange, than a tad of blue and finally it is white hot.

Red is the lowest frequency of visible light, so it requires the least heat energy. The glowing white hot horseshoe is emitting all the colors, so lots of energy is needed.

Some of the main ideas of quantum physics: Energy is not continuous but comes in small but discrete units. Electrons behave both as waves and as particles; movement of these particles is random and not predictable. One can’t know both the position and velocity of the particle at the same time.

The obvious question then is: What good is quantum mechanics? Much of our modern technology rests on quantum physics. The laser, transistor, microchip, LEDs, MRIs, the electron microscope, flash drives on the USB and superconductivity all depend on quantum effects.

And finally, the quantum theory settled a centuries-old debate about the nature of light. The English scientist, Isaac Newton, claimed that light was a particle, but the Dutch scientist, Christiaan Huygens, showed that light is a wave. The quantum theory married these two seemingly competing ideas in one, stating that matter can behave as a wave and a wave can act as matter.

Larry Scheckel is a retired Tomah High School physics teacher.


Steve Rundio is editor of the Tomah Journal. Contact him at 608-374-7785.

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