Kilogram Redefined. The Metric System Overhaul Is Complete El Kilogramo redefinido de acuerdo a la constante de plack.Since 1879, the kilogram has been defined as the exact mass of the International Prototype of the Kilogram (IPK) […] A better option is to develop a new definition based on a mathematical foundation that can be calculated anywhere, and the Planck constant fits the bill […]. To measure the Planck constant, the researchers used a Kibble balance, a device that suspends a 1-kg weight with electromagnetic forces. They can calculate the constant according to the amount of electromagnetic energy it takes to balance the mass. Source.