Category Archives: NIST

This gizmo, observed at NIST, is a Raleigh current balance and was used in the classic 1912 determination of the absolute value of the ampere. It was also used in 1938 to redefine the international ampere as 0.99985 absolute amperes:

A couple of weeks ago, I visited NIST. This gizmo, which tests how much abrasion a dollar bill can stand, blows my mind (you can see the dollar bill on the right):

I recently had occasion to visit NIST, the National Institute of Standards and Technology, which provides measurement standards. For example, most networked clocks use NIST’s Internet Time Service which sets computer clocks and other networked timekeeping devices. But they also … Continue reading →