What Is Physics?

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Physics is the scientific study of matter and energy and how they interact with each other. This energy can take the form of motion, light, electricity, radiation, gravity . . . just about anything, honestly. Physics deals with matter on scales ranging from sub-atomic particles (i.e. the particles that make up the atom and the particles that make up those particles) to stars and even entire galaxies.

How Physics Works

As an experimental science, physics utilizes the scientific method to formulate and test hypotheses that are based on observation of the natural world. The goal of physics is to use the results of these experiments to formulate scientific laws, usually expressed in the language of mathematics, which can then be used to predict other phenomena.

When you talk about theoretical physics, you are speaking of the area of physics that is focused on developing these laws, and using them to extrapolate into new predictions. These predictions from theoretical physicists then create new questions that experimental physicists then develop experiments to test. In this way, the theoretical and experimental components of physics (and science in general) interact with each other, and push each other forward to develop new areas of knowledge.

The Role of Physics in other Fields of Science

In a broader sense, physics can be seen as the most fundamental of the natural sciences.

Chemistry, for example, can be viewed as a complex application of physics, as it focuses on the interaction of energy and matter in chemical systems. We also know that biology is, at its heart, an application of chemical properties in living things, which means that it is also, ultimately, ruled by the physical laws.

Of course, we don't think of these other fields as part of physics. When we investigate something scientifically, we look for patterns at the scale that is most appropriate. Though every living thing is acting in a way that is fundamentally driven by the particles of which it is composed, trying to explain an entire ecosystem in terms of the behavior of fundamental particles would be diving into an unhelpful level of detail. Even when looking at the behavior of a liquid, we look in general at the properties of the fluid as a whole through fluid dynamics, rather than paying particular attention to the behavior of the individual particles. 

Major Concepts in Physics

Because physics covers so much area, it is divided into several specific fields of study, such as electronics, quantum physics, astronomy, and biophysics.

Why Is Physics (Or Any Science) Important?

Physics includes the study of astronomy, and in many ways astronomy was humanity's first organized field of science. Ancient peoples looked to the stars and recognized patterns there, then began using mathematical precision to make predictions about what would happen in the heavens based on those patterns.

Whatever flaws there were in these specific predictions, the method of trying to understand the unknown was a worthy one.

Trying to understand the unknown is still a central problem in human life. Despite all of our advancements in science and technology, being a human being means that you are able to understand some things and also that there are things you do not understand. Science teaches you a methodology for approaching the unknown and asking questions that get to the heart of what is unknown and how to make it known.

Physics, in particular, focuses on some of the most fundamental of questions about our physical universe. Pretty much the only more fundamental questions that could be asked fall in the philosophical realm of "metaphysics" (named for being literally "beyond physics'), but the problem is that these questions are so fundamental that many of the questions in the metaphysical realm remain unresolved even after centuries or millenia of inquiry by most of history's greatest minds.

Physics, on the other hand, has resolved many fundamental issues, even though those resolutions tend to open up whole new types of questions.

For more on this subject, look into our articles "Why Study Physics?" and "Grand Ideas of Science" (adapted, with permission, from the book Why Science? by James Trefil).