Physics is the science devoted to the study of matter and energy. Physicists try to understand what matter is and why it behaves the way it does. They seek to learn how energy is produced, how it travels from place to place, and how it can be controlled. Physicists are also interested in how matter and energy are related to each other and how they affect each other over time and through space.
The word physics comes from a Greek word meaning natural things. Knowledge obtained from the study of physics is important in other sciences, including astronomy, biology, chemistry, and geology. There is also a close connection between physics and practical developments in engineering, medicine, and technology. For example, engineers design automobiles and airplanes according to certain principles of physics. Laws and theories of physics have enabled engineers and scientists to put satellites into orbit and to receive information from space probes that travel to distant regions of the solar system. Research in physics has led to the use of radioactive materials in the study, diagnosis, and treatment of certain diseases. In addition, theories and principles of physics explain the operation of many modern home conveniences, from vacuum cleaners to videotape recorders.
