Making estimates: The smallest dust particle visible to the unaided human eye
measures about 0.05 mm across. About how many atoms across is this - in other
words, if we line up atoms side by side, about how many would it take to make
a line of atoms 0.05 mm long?
Answer:
The diameter of an atom is about
, and the dust particle
measures 0.05 mm =
across. Therefore the number of
atoms needed to be lined up to make a length equal to the lenght of the dust
particle is
It takes half a million atoms.