# Physicist

The discipline of physics is specialised in the interactions of matter and energy at all length and time scales in the physical world. A **physicist** is a scientist who specialises in this area of science. Physicists are typically interested in the underlying or ultimate causes of events, and they tend to frame their knowledge of these phenomena in terms of mathematical equations and concepts. A broad variety of study areas, covering all length scales, are explored by physicists: from sub-atomic and particle physics through biological physics and cosmology, to cosmic length scales that include the whole universe. Experimental physicists, who specialising in the observation of natural events and the analysis of experiments, and quantum physicists, who specialise in the mathematical modelling of physical systems in order to rationalise, explain, and predict natural phenomena, are the two main types of physicists in the field of physics. Physicists may put their expertise to use in addressing real issues or in the production of new technology (also known as applied physics or engineering physics).