Physics is a natural science that involves the study of matter and its motion through space-time. The study of physics also deals with related concepts, such as energy and force. It can be defined as the general analysis and the study of nature and gaining an understanding of how the universe behaves. The word physics derives from the Ancient Greek word 'physis', which means 'nature'.

The major branches of physics are:

• Classical mechanics - the physics of forces acting upon bodies

• Thermodynamics and statistical mechanics - the effects of changes in temperature, pressure and volume and the transfer of energy as heat

• Electromagnetism - the interaction of charged particles with electric and magnetic fields

• Relativity - divided up into 'special relativity' and 'general relativity' and based on Albert Einstein's theories and proposals

• Quantum mechanics - the interaction of atomic and subatomic systems with radiation

• Statistical mechanics - the application of probability theory to the study of thermodynamic behavior.

In the modern day, contemporary research into physics can be broadly divided into the following areas of study:

• Condensed matter physics

• Atomic, molecular and optical physics

• Particle physics

• Astrophysics

• Geophysics

• Biophysics

In recent decades, the individual fields of physics have become more and more specialized, and most physicists will therefore work in one specific field for the entirety of their careers. 'Universalists' such as Einstein and Lev Landau are now rarities in the modern age.