Physics is the study of matter, energy, and their interaction. It is divided into several main branches including mechanics, electricity, solid state physics, biophysics, and electromagnetism. Mechanics deals with the motion of macroscopic objects and the forces that cause changes in their position. Electricity studies phenomena related to electric charges, while solid state physics examines the structure and properties of solid materials. Biophysics applies the laws of physics to biological phenomena, and electromagnetism investigates the electromagnetic force between electrically charged particles.