The prefix nano- means 1 billionth, so in theory 1 billion carbon atoms put
end to end would stretch 1 meter. The symbol for nano- is n so nm would
stand for a nanometer.
I couldn't find easy examples of yotta, zetta, exa, femto, zepto, or
yoctometers but you get the idea that they are very big or very small
measurements.
The prefixes can be used with any scale of measurement. A milligram is
1/1000th of a gram. A kilogram is 1000 grams. 1000 kilograms is a megagram,
although it is simply called a metric ton.
Measurements can be traced back to water. 1 milliliter of water = 1 cm3
(cubic centimeter) of water = 1 gram of water. It takes one calorie of energy
to heat one gram of water by 1 degree.
