Quantum mechanics (QM) is the branch of physics that studies the behavior of particles at a microscopic level, such as atoms and subatomic particles. It describes how these particles interact with each other and with energy, and provides a framework for understanding the fundamental laws of nature.
Classical mechanics is the branch of physics that studies the behavior of objects at a macroscopic level, such as how a ball moves when it is thrown. QM differs in that it takes into account the wave-like behavior of particles at the microscopic level and does not follow the same rules as classical mechanics.
QM has numerous practical applications in fields such as electronics, chemistry, and materials science. Some examples include transistors, lasers, and magnetic resonance imaging (MRI) technology.
QM developed in the early 20th century as physicists began to study phenomena at the atomic level and realized that classical mechanics could not fully explain their observations. Scientists such as Max Planck, Albert Einstein, and Niels Bohr made significant contributions to the development of QM.
No, QM is not considered a complete theory as it does not fully explain all aspects of the universe, such as gravity. It also conflicts with the principles of general relativity, which describes the behavior of objects on a large scale. There is ongoing research and debate in the scientific community to try and reconcile these theories and develop a more complete understanding of the universe.