Water has a density of 1000 kg/m3 by standard definition at its temperature of maximum density 3.98 Â°C and at 0% salinity. Scientists and engineers use water as a baseline for comparing the relative density of various materials. Water with a density of 1000 kg/m3 at 3.98 Â°C has a mass of 1000kg and a volume of 1 m3.
Spelt is a word. It is the past participle of spell. It is also a type of wheat, and therefore also a noun. It depends upon whether you are using British English (and Spelt is correct) or you are using American English.
It is spelt by us with a y in the first syllable, as it was spelt with the corresponding in the Greek.