A part of the problem compounding students’ fears of physics is its vocabulary: those lofty scientists seem to speak a language all their own, with just a few words of English thrown in!

With the rare exception of Stephen Hawking, who gave the world an explanation of the cosmos in everyday terms with his A Brief History of Time.

But, really, the language of physics is not that hard to grasp if you know the key terms and word groupings.

That is why your Superprof presents you with this physics glossary!

Unlike a dictionary that might define a word but leave you no clearer on its meaning in a scientific context, we aim to put a bit of meat on each word’s bones so that you can truly sink your teeth in and get a good bite on the matter.

Along the way, we’ll include a bit of extra information so you can see how each term fits within this discipline called physics.

Names of the Different Branches of Physics Study

Newton's balls are a classic example of conservation of momentum
Newton's cradle operates on a classical theory of momentum conservation Source: Pixabay Credit: 849356

Physical science is broken into two broad categories: classical physics and modern physics. The rule of thumb distinguishing them is very simple:

Any discovery made prior to 1900 is generally considered classical. Anything established after 1900, even if built on a classical theory, is considered modern – as long as it resulted in a new avenue of research and/or discussion.

Should you pursue studies and research in classical physics, your work might incorporate:

  • classical mechanics: the study and analysis of objects visible to the naked eye, including planets, stars and galaxies

  • Newton’s Laws of Motion, describing the correlation between a body and the forces acting on it

  • Thermodynamics: temperature in relation to energy and work (work is not meant in the ordinary sense!)

  • Einstein’s Relativity theories: special relativity and general relativity

  • Chaos Theory

Perhaps the best way to grasp the principle of chaos theory is to put it in the context of a real-life application. For our purposes, predicting the weather would work.

On the surface, weather patterns seem quite random: one day it rains and the next day is sunny, and then we have mild temperatures before the mercury drops precipitously and we have to rush for woolly socks and warm jumpers.

As apparently unpredictable as those weather changes can be, there is a pattern to them that is driven by multiple factors.

Weather, with its humidity and jet streams, is considered a dynamical system – a system that moves.

When you have a dynamical system that is sensitive to initial conditions, you may analyse its behaviour over time using mathematics, thus permitting a prediction of its future behaviour.

However, as mathematician Edward Lorenz said: the present determines the future but the approximate present does not approximately determine the future.

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That is the very definition of Chaos Theory.

Discover other cool physics facts related to classical physics!

Can you spot the patterns in this random chaos?
Within seemingly random chaos are repeating patterns Source: Pixabay Credit: Ninocare

What About Modern Physics?

Because of technological and intellectual limitations of its discovery period, classical physics lacks a depth of explanation that can only be provided through modern theories such as quantum mechanics, and/or by using Einsteinian relativityas opposed to Galilean relativity.

The essence of modern physics deals with extremes: either very small particles or very large aspects or properties of matter; long distances or high speeds.

The ‘middles’, as they are called, are usually addressed by classical physics.

An apt way to describe this difference would be the behaviour of a gas. Studies conducted at 0º Celsius might be a matter for the classical study but that same gas, at absolute zero – -273.15º Celsius would be of interest to anyone conducting modern physics research.

Absolute zero represents the total absence of heat; it is the lowest limit on the thermodynamic temperature scale.

If you are an undergraduate majoring in physics, you wouldn't declare yourself a classical or modern physicist because modern physics depends heavily on classical theories.

Unlike in music, where one could specialise in playing classical piano or modern jazz piano, one needn’t elect to practice classical physics or modern physics.

However, as an aspiring physicist, you could choose a specific field of physics in which to apply yourself.

Let’s examine some of them, now.

Also, take a closer look at pioneering physicists and their discoveries!

Physics Terminology

If you are mad for The Big Bang Theory, you might aspire to follow in Sheldon’s footsteps to become a theoretical physicist: that would call for you to use mathematical equations to predict the outcome of theories.

However, if Leonard is your fav, you could emulate him by becoming an experimental physicist – the complement to your theoretical counterpart, you would conduct actual experiments and record your results.

Raj is an astrophysicist, studying the nature of cosmic bodies rather than their position and how they move in space.

Particle physics, also known as high energy physics involves the study of particles that make up matter and radiation. Note that particle, in this sense, could be anything from electrons to dust.

Applied physics suggests you could help develop new technologies or help solve a thorny engineering problem regarding such development. Indeed, this branch of physics is the link between scientific study and engineering.

Biophysics borrows methods of analysis used in physics to study any biological phenomenon.

Atomic physics: you know those nifty diagrams of shells and valences and electrons in your science books? They were conceived by atomic physicians, who study the composition and structure of atoms.

There is a difference between atomic physics and nuclear physics in spite of the synonymous usage in English of the words atomic and nuclear.

Nuclear physics concerns itself solely with the nucleus of an atom. Have you ever had an MRI? It and other facets of nuclear medicine such as PET scans and other spectroscopy came about through discoveries in nuclear physics!

Condensed matter physics involves studying the behaviour of solids and liquids using various physical laws.

This field of research is a crossroads where several disciplines meet: theoretical physics, particle physics and nanotechnology blend with chemistry and all of the areas formerly known as solid state physics.

It is also one of the most active fields of study in contemporary physics because of its sheer breadth and diversity of materials to study.

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Some physicists might have quark for breakfast; other study them all day
This is generally not the image that comes to mind when a physicist thinks of quarks! Source: Pixabay Credit: RitaE

General Physics Vocabulary

Now that we’ve looked at some physics specialities you might consider for your career, let’s drill down to the verbiage used by this discipline – some of which might even sound familiar to you!

Quark: you might know this word as the name of a dairy product but, in physics, it represents an elementary particle.

However, to make matters more confusing (physical) quarks come in 6 flavours: up, down, top, bottom, charm and strange. Dairy quark is generally unflavoured!

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Quarks always feature in configurations of three: one up/two down; two top/one bottom and so on.

A hadron is two or more quarks held together by the strong force.

Any time you hear hadron, boson or fermion, you now know those names represent classes of subatomic particles.

Ever heard of a hadron collider? Now you know what it was named after!

A neutrino is not the hippest neutron in the atom; it is a subatomic particle with no electrical charge and very small mass. It travels very quickly; close to the speed of light!

Quantum: this word is used a lot in physics, from describing discrete fields of study (quantum chromodynamics) to delineating entire branches of physics, such as quantum field theory.

Used by itself, quantum represents the smallest possible unit anything can be divided into: at the quantum level, e.g.

An isotope is a possible form of an element. Two or more elements may have the same number of protons but vary in the number of neutrons in the nucleus.

Perhaps the most renown of such elements is uranium-235, which differs from uranium-238 because it has 3 fewer neutrons, even though they are both the element identified as uranium. (Uranium-235 is used in nuclear power stations and to make nuclear weapons).

We tend to think of waves as something the ocean generates or something we do with our hands, but physicists associate waves with any disturbance that transfers energy through matter or space.

Waves can be either a vibration or an oscillation, of a physical medium or of a field, around essentially fixed locations. The two main types of waves are mechanical or electromagnetic.

Can you guess what type of wave your microwave oven puts out?

Please feel free to discover more key concepts in physics, served up in a nutshell for your easy digestion!

Theoretical physics, astrophysics or plasma physics: as you contemplate which branch of physics you would make your mark in, take comfort in knowing that, someday, through your hard work, you may get to name a vital element or particle that future students will have to learn about!

Higgs boson, anyone?

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A student by trade, Daniel spends most of his time working on that essay that's due in a couple of days' time. When he's not working, he can be found working on his salsa steps, or in bed.