Geology is the study of the Earth in all its aspects except those that are now considered to be separate sciences of the Earth, like geophysics and meteorology. It concerns the materials of which the Earth is made, and the processes that operate on them. Very many of these processes are physical, and their understanding involves an understanding of the underlying physics. The raindrop that falls and makes its contribution to erosion is first created by condensation, falls under the influence of gravity, is held together by surface tension, reaches its terminal velocity as a result of friction long before hitting the Earth, has potential energy during its fall, and kinetic energy that is converted to mechanical energy and work when it strikes the Earth. <...>
