The State of the Unit: a documentary film about the redefinition of the kilogram


A snowflake fragment on half-sized replica of the IPK, made by the Murakami Koki Company and given to me by Noboru Murakami. I have read repeatedly that from 1889 to 1989 the IPK has lost about 50 micrograms, or the weight of a fingerprint or an "average snowflake." But snowflakes come in many sizes, and are typically measured by diameter not mass.