Why do we need to redefine mass?
The current SI unit of mass i.e. Kilogram is defined as mass equal to the mass of 1 dm3 of water at its maximum density, approximately 4 °C. It is also defined as being equal to the mass of the International Prototype of the Kilogram (IPK). The IPK is made of a platinum alloy known as “Pt‑10Ir”, which is 90% platinum …