The common metric prefixes are given below. The base units of length and volume are linked in the metric system. The base units of volume and weight are also linked. The gram was originally defined as the mass of 1 mL of water at 4 degrees Celsius. Problem Mass Versus Weight Mass is a measure of the amount of matter in an object, so the mass of an object is constant.
Weight is a measure of the force of attraction of the earth acting on an object.
The weight of an object is not constant. Mass is a more fundamental quantity than weight. There is no English equivalent to the verb weigh that can be used to describe what happens when the mass of an object is measured. You are therefore likely to encounter the terms weigh and weight for operations and quantities that are more accurately associated with the term mass . In 1960 the International System of Units was proposed as a replacement for the Metric System.