An optical microscope is a scientific instrument that uses visible light and a system of lenses to magnify small objects. It allows users to see details that are not visible to the naked eye, making it essential in fields like biology, materials science, and medicine. The basic components include an objective lens, an eyepiece, and a light source. These microscopes can achieve magnifications typically ranging from 40x to 1000x, depending on the lenses used. They are commonly used to examine cells, tissues, and microorganisms, providing valuable insights into their structure and function.