A microscope is an optical instrument with lenses that reveal details of an object which are invisible to the naked eye. The degree of useful magnification provided by a microscope depends on the wavelength of the light source and the quality of the lenses. Even with perfect lenses and lighting, an optical microscope is only helpful for studying objects larger than half the wavelength of white light. In practice, the maximum magnification is about 1,000 times. To see even smaller particles, we need greater magnification. This requires a shorter wavelength than visible light. For this purpose, we use electron microscopes with electromagnetic lenses and specialised detectors. Instead of light, these microscopes use high-energy electrons.