A microscope is an instrument that magnifies objects, enabling visibility of 1,000 times or more than what can be seen by the naked human eye. Microscopes of various types assist researchers with medical diagnostics, and they have aided scientists in attaining knowledge of biology and material science.
Optical microscopes, which are the oldest design of microscopes, are often used for teaching purposes in biology classrooms. These instruments work by using a small, spherical lens, referred to as an objective lens that is contained within the microscope's tube. The objective lens is aimed at an illuminated object that is brought into focus. A second lens, known as the ocular lens, magnifies the image for enhanced viewing.
Because light is used to image the object, optical microscopes were limited in their use until the availability of electrical light sources. The origins of the microscope are a subject of debate. However, its invention in the late 1500s is often attributed to Zacharias Jansen, a Dutch eyeglass maker.
There are other types of more sophisticated microscopes that function differently from the optical microscope. Digital microscopes use digital cameras to view images. The electron microscope, developed in the early 1900s, uses electrons for imaging objects. Due to the high magnification power of electron microscopes, they serve as important instruments for medical and scientific research.