What is physics?

©Fernando Caracena 21 September 2012



Richard Feynman) a Nobel Prize winner in physics said,

“Physics is what physicists do late at night.”

That is what I did my first graduate school year at Case Western. I would stay up late into the night reading books in the physics library and doing problems. Afterwards, a group of us would go for a late snack of pizza and beer, and perhaps discuss more physics.

Physics is an experimental science

The first choice I was confronted with on entering graduate school was “what do you want to be, an experimentalist or a theorist?” The graduate students who were doing experiments would spend day and night minding their experimental equipment, which was usually elaborately electronic in the form of some kind of Rube Goldberg device. Experimental design did not need look pretty. It was made to do the job and to do it rapidly and efficiently. When the experiment was finished, the device was taken apart and its components re-shelved. Friends of mine who chose to do this kind of physics, called themselves experimentalists.

I liked doing experiments and working with the laboratory equipment; but, I noticed that student experimentalists would spend long hours in the laboratory often neglecting their studies. I wanted to get the most out of graduate school, so I became a theorist.

Physics is what physicists do

Physicists describe physics in another way than as in Feynman's above quote, “Physics is what physicists do late at night.” Physicists use their minds in a powerful way that has driven the technological development of the human race. We know that what physicists do has an important effect on all our lives and society. The development of the atomic bomb was the work of physicists. Physics is not bomb making, but the knowledge that physicists have and understanding of nature that they have developed can be used to make bombs. Physical knowledge is a two edged sword. It can better mankind by elevating our standard of living; taking us to the Moon; giving us a means to explore the planets; developing fantastic electronic devices; and motivating the computer-Internet revolution.

The text book answer is that physics is one of the natural sciences, originating from in a branch of philosophy that the ancient Greeks called natural philosophy. Aristotle wrote a book on physics ("Physicae Auscultationes," meaning "lectures on nature") ,which was a definitive book at its time, but is now obsolete.

The reason that physicists do not define physics too closely is that the advance of physics bursts old definitions like, “physics is the science of matter and motion.” Instead physicists emphasize aspects of physics that they do not expect to change with time, such as:

  • physics is an experimental science
  • the language of physics is mathematics
  • physics is fundamental science.

In summary, I would propose the following definition:

Physics is the science of fundamental patterns in nature especially those involving transformations, which are observed in time and space.

The patterns that we observe in nature ore generated by two streams: energy and information.

Mathematics is the science of patterns.

What motivates Physicists

I became a physicist long before I realized that I was one. The world of nature was mysterious and awesome. My father, who always wanted to become a chemist, became an accountant instead, but kept a number of science books on his library shelf. One series of books contained various courses in the sciences, such as physics, chemistry and astronomy. I spent many hours reading these books while I was still in grammar school. But, I did not confine all my attention to books. I was interested in playing around with electricity and magnetism. Miraculously, I escaped electrocuting myself when I played with high voltage currents. I also made friends with other kids with similar interests. We had a frog collection. We made ad hoc telescopes out of reading glass lenses that had long focal lengths, as long as twelve feet. By attaching such a lens to the eave of a house, and using a short focal length lens (say half inch) as an eyepiece, we had a high-power telescope (over 100x) that we could use to view a bright source of light in the sky, such as the Moon. The view was clear enough  its craters vivdly.

Was there any life out there? I had read about Percival Lowell's (1855–1916) "canals" that he imagined as he gazed through the telescope at Mars. Science fiction gave the straight answer--of course there s plenty of life out there, even humanoids. Science fiction was entertaining, but I knew the difference between fact and fiction. Still, I wondered and imagined. Perhaps on Olympus Mons, in some of its steamy cracks there was life on Mars, little wormy creatures crawling on moss.

When I attended high school, my grades improved dramatically, because what I liked, I could now take as a course. Before then, what interested me was not a school subject. For the first time, I was able to indulge my own interests, which many students avoided because they considered them difficult subjects. I excelled in science, making straight A averages. In physics, I did better than that, A+s.

All Kinds of Minds

What life has taught me is that we are all born with unique minds and tendencies toward different skills. These are all necessary components of being human, and the working of these different kinds of people is what has produced the success of humanity.

Physicists are born with a unique mindset, skills, and mathematical loves that draw them into the study of the mysteries of nature at a fundamental level. When they mature, they call themselves physicists; and what they do, they call physics. What they find is mystery and excitement.


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