Inventor: Max Knott and Ernst Ruska

• Invented in 1931
• Uses electrons to magnify an object up to one million times

An electron microscope speeds up electrons in a vacuum until they have a wavelength of only one hundred-thousandth that of white light. Beams of the electrons are focused on a cell sample and are absorbed or scattered by the cell to form an image on a photographic plate Electron microscopes make it possible to see objects as small as an atom, and are typically used to see biological molecules. They can magnify objects up to one million times. However, no living cell can be seen, as none can survive under the high vacuum. Despite this, electron microscopes have played a major part in biological discoveries and led to the creation of the scanning tunneling microscope.

Picture from Encarta Encyclopedia.

Bellis, Mary. "The History of the Microscope." About.com. Available 10 April 2004. <http://inventors.about.com/library/
inventors/blmicroscope.htm#Germans>

• This website had some basic information about the electron microscope, including a brief description of how it works and what it can do.