What is a micron?
A micron is one millionth of a meter, or 0.000001 meters. Its symbol is µm, the Greek letter mu followed by m.
'Micron' is the older name for the micrometer, and the SI dropped it in 1967. It survives on filter ratings anyway – a 5 micron filter catches particles down to about 5 micrometers.
What is a centimeter?
A centimeter (cm) is one hundredth of a meter and just under four tenths of an inch (0.3937 inches). The prefix comes from the Latin centum, a hundred.
Divide centimeters by 30.48 to get feet, or multiply feet by 30.48 to get centimeters. The factor is exact, as a foot is 30.48cm, and a single centimeter is about 0.0328 feet.
The centimeter was the base unit of length in the CGS (centimeter, gram, second) system that physicists used before SI, which is why older physics talks about dynes and ergs.