In the field of forensic science, various machines are used to examine physical evidence. One of these instruments is the scanning electron microscope (SEM). This instrument can be used to examine physical evidence found at crime scenes. A number of scientists have developed and improved SEM. SEM is very important in forensic science because it can refine the size, shape and chemical composition. The scanning electron microscope is constantly growing and has a great impact on forensic science. We'll start by learning where the scanning electron microscope (SEM) began. Knoll built the first scanning microscope in 1935; he did not use roughing lenses. Von Ardenne expressed the theoretical philosophy behind the scanning electron microscope. Zworykin developed the first scanning electron microscope in 1942. This microscope was improved by using an electron multiplier tube as a preamplifier of the secondary electron emission current. The resolution on the SEM was 50 nm (Physics Emory). Improving on the SEM developed by Zworykin, Oatley used nonlinear signal amplification. He was also the first to place a stigmator in the SEM, used to correct cylindrical imperfections in the lens. In 1960, Everhart and Thornley improved the detection of secondary electrons. Three years later, Pease and Nixon combined all the improvements into a single microscope. The first commercial scanning electron microscope was developed in 1965 by Cambridge Scientific Instruments Mark I (Physics Emory). The scanning electron microscope includes 10 parts which are secondary detector, x-ray detector, backscatter detector, sample chamber, objective. , electron beam, condenser lens, anode, ...... middle of paper ...... nated is very important in criminal cases. We reviewed the history and parts of SEM, how it works, how it can help solve cases, and a real case in which it was used to find the murderer. The scanning electron microscope is very important and it will continue to be so in the future. Works Cited Atteberry, J. (nd). How it works: How scanning electron microscopes work. Retrieved from How stuff works: http://science.howstuffworks.com/scanning-electron-microscope2.htm Khursheed, A. (2011). Optics and spectrometers of the scanning electron microscope. Danvers: World Scientific Publisher. Physics Emory. (nd). Retrieved from Physics Emory: http://www.physics.emory.edu/~weeks/lab/papers/bogner-micron07.pdf Swapp, S. (nd). Geochemical instrumentation and analysis. Retrieved from Carleton: http://serc.carleton.edu/research_education/geochemsheets/techniques/SEM.html