why is liter capitalized. it is not a noun it is a quantity. Are all the units of measurement also capitalized
Based solely on the German Wikipedia article for the SI, I believe so. http://de.wikipedia.org/wiki/Internationales_Einheitensystem
From School House Rock: "A noun is a person, place, or thing." (They missed general ideas, such as "happiness," but that could theoretically count as a thing.) A liter is a thing. It's a noun; therefore, it's capitalized.