Classical physics

Classical physical concepts are often used when modern theories are unnecessarily complex for a particular situation.

Beginning at the atomic level and lower, the laws of classical physics break down and generally do not provide a correct description of nature.

From the point of view of classical physics as being non-relativistic physics, the predictions of general and special relativity are significantly different from those of classical theories, particularly concerning the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light.

According to the correspondence principle and Ehrenfest's theorem, as a system becomes larger or more massive the classical dynamics tends to emerge, with some exceptions, such as superfluidity.

This is why we can usually ignore quantum mechanics when dealing with everyday objects and the classical description will suffice.