Physicists in the US say that they have used publicly available data from global positioning system (GPS) satellites to put a limit on how much Planck’s constant might vary from place to place. Their ...

For nearly 130 years, the kilogram has been defined by a small platinum and iridium cylinder sitting in a vault outside Paris. Every other unit of measurement is defined by reproducible physical ...

Researchers at the National Institute of Standards and Technology (NIST) have made their most precise determination yet of Planck’s constant. This will let NIST redefine the kilogram, the official ...

Lego is a popular Christmas gift, and young and old alike can derive hours of pleasure building with those little plastic blocks. But, like a lot of playthings, the novelty wears off soon enough and ...

Planck’s constant is one of the most important numbers in science. It describes the relationship between the energy and frequency of an electromagnetic wave in an equation known as the Planck-Einstein ...

A high-tech version of an old-fashioned balance scale at the National Institute of Standards and Technology (NIST) has just brought scientists a critical step closer toward a new and improved ...

What does a kilogram weigh? Middle school science classes often teach that the unit is based on the weight of water—specifically a cube of water, a tenth of a meter on each side, at just above ...