Biophysics is the science that asks how the rules of physics show up inside living things. Physics is about force, energy, light, heat, and movement. Biology is about plants, animals, cells, and the body. Put them together and you get questions like: how does a muscle pull? how does the eye catch light? how does a nerve send a signal? how does blood move? People who do this work are scientists, usually in a university or a hospital lab. The word is formal. You will meet it on course names and papers, not in the market. Though actually, a lot of modern hospital tools — the ones that use magnets, sound, or radiation to look inside the body — rest on this kind of thinking, even when nobody says the word out loud. It is not the same as biochemistry, which looks at the chemistry of life. Biophysics cares more about force, energy, and physical laws inside living systems.