Carl Sagan looks at the planets Jupiter and Saturn by examining the work of Galileo, Huygens, and the Voyager probes.
Did You Know?
We see Leeuwenhoek using his microscope to look at a drop of water on the side of a waterglass. The microscope is at least three inches from the glass, and two inches from Leeuwenhoek's eye. That design has a sample holding pin less than 1/4 inch from the lens, and can only be used to see what is on the end of the pin. Also, you must hold the device very, very close to your eye to see anything. See more