A Transmission Electron Microscope (TEM) is a powerful tool used to observe the internal structure of very small samples at high magnifications. It works by transmitting a beam of electrons through a thin specimen, allowing scientists to see details at the atomic level. This technique is essential in fields like materials science, biology, and nanotechnology. TEMs require samples to be extremely thin, typically less than 100 nanometers, to allow electrons to pass through. The resulting images provide valuable information about the arrangement of atoms and the overall morphology of the sample, aiding in research and development across various scientific disciplines.