In this video, the woman says that a sphere is a pretty simple object. What intrigues me is the use of a sphere for such a calculation. First of all, the sphere wouldn't be perfect as a perfect sphere ...
Possible Duplicate: Why do we still not have an exact definition for a kilogram? I was thinking about SI units. I found the following definition for the base units: Meter: distance ...
Could I get an explanation of Avogadro's number and how it relates to determining the mass of a substance? My chemistry textbook only serves to confuse me and the Wikipedia article is aimed towards a ...