Why Isn't a Kilogram a Kilogram?

The video discusses the kilogram, the basic unit of mass in the metric system, and its historical development. Initially defined by the weight of water, the kilogram became an international standard in 1875. However, the physical prototype used to define it has become unreliable, with its mass drifting over time. Scientists aim to redefine the kilogram using the Planck constant, a universal constant, to ensure precision. This involves using a Watt balance to measure mass in terms of electric current and voltage. The goal is to establish a new definition by 2018, eliminating the need for physical prototypes.

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