physics

Physics is the natural science that studies matter, energy, space, and time and the interactions between them. It seeks to formulate models and laws that describe how the universe behaves across scales, from subatomic particles to galaxies.

Major branches include classical mechanics, electromagnetism, thermodynamics and statistical mechanics, quantum mechanics, and relativity. Interdisciplinary areas include condensed matter physics, optics, acoustics, plasma physics, particle physics, astrophysics, and biophysics.

Method: Physicists use observation, experiment, and mathematical reasoning to develop predictive theories. The scientific method involves forming hypotheses, testing them with controlled experiments and simulations, and refining explanations to describe phenomena and forecast new results.

History: Physics has roots in ancient natural philosophy and was transformed by figures such as Galileo, Newton, Maxwell, and Einstein. Landmark ideas include Newton's laws of motion, Maxwell's equations, the principles of thermodynamics, and the theories of relativity and quantum mechanics.

Key concepts: energy, force, momentum, fields, waves, and particles; wave–particle duality; quantization; superposition and interference; the uncertainty principle; symmetry and conservation laws.

Applications: Physics underpins modern technology and industry, including electronics, communications, medical imaging and radiation therapy, energy production, materials science, and space exploration. It also informs chemistry, biology, and environmental science.

Education and research: Careers typically require university study in physics or related fields. Research is conducted at universities, national laboratories, and industry, often through collaborative projects and peer-reviewed publications.