the second most common kind are a few kinds of electron microscopes. transmission electron microscopes (tems) fire cathode rays into the object being looked at. this carries information about how the object looks into a magnetic "lens". the image is then magnified onto a television screen. scanning electron microscopes also fire electrons at the object, but in a single beam. these lose their power when they strike the object, and the loss of power results in something else being generated—usually an x-ray. this is sensed and magnified onto a screen. scanning tunneling microscopes were invented in 1984.