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Taking Measure Blog Posts

Time and frequency

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overlapping wavelengths of light enter from the left and pass into the optical frequency comb device. The image shows a visualization of the different wavelengths separated into even increments.

Making Measurements With a Fine-Toothed Comb

September 15, 2021
Rebecca Jacobson
To many people, a measurement sounds mundane, like marking ticks on a ruler or reading the line on a thermometer. It’s a piece of data. And they tend to think that improved measurements look like finer and finer ticks on a ruler — which doesn’t seem very exciting. But making new measurements is more
digital clock in orbit around Earth. The clock face reads 11:59:60.

Everyday Time and Atomic Time: Part 5

April 23, 2021
Judah Levine
This is part 5 in a series. Read part 1 , part 2 , part 3 and part 4 . The Leap Second Solution When atomic clocks were developed in the 1950s, scientists needed to match the time and frequency of these new devices to the long-standing astronomical definitions of these same parameters in order to
pair of feet standing on either side of the prime meridian in Greenwich, England

Everyday Time and Atomic Time: Part 4

April 20, 2021
Judah Levine
This is part 4 in a series. Read part 1 , part 2 and part 3 . Greenwich Mean Time In the previous essay I introduced mean solar time, which averaged the annual variation in apparent solar time so as to generate a time scale that was more consistent with the time scale generated by clocks that used a
wood pendulum clock hung on a wood paneled wall

Everyday Time and Atomic Time: Part 3

April 9, 2021
Judah Levine
This is part 3 in a series. Read part 1 and part 2 . Oscillators and Clocks In the previous essay, I introduced the ideas that frequency and time interval are closely related concepts, and that the time at any instant is a count of the number of basic time intervals (such as the second) that have
pipe organ

Everyday Time and Atomic Time: Part 2

April 5, 2021
Judah Levine
This is part 2 in a series. Read part 1. A short history of frequency Frequency was originally considered to be the province of musicians. The pitches or frequencies of the notes in a musical scale are defined by ratios — octaves, for example, where the frequency of the higher note is twice the
NIST physicist Judah Levine with the NIST time scale, a digital clock face reading 14:33:34 and a bank of atomic clocks.

Everyday Time and Atomic Time: Part 1

March 16, 2021
Judah Levine
As a physicist in the National Institute of Standards and Technology (NIST) Time and Frequency Division, I have worked in the general area of operating atomic clocks and using output signals from them to distribute time and frequency information for more than 40 years. I am also a Fellow at JILA, an
Josephson voltage standard chip with penny for scale

From 1901 to 2021: Measurements Then and Now

February 25, 2021
Mark Esser
A lot has changed at the National Institute of Standards and Technology (NIST) in the past 120 years. For one thing, we were known as the National Bureau of Standards for the first 87 years of our existence. Then, in 1988, we became the National Institute of Standards and Technology (NIST), to
NIST physicist Elizabeth Donley and Compact Atomic Clock

Keeping Time at NIST

June 18, 2020
Mark Esser
Einstein is reported to have once said that time is what a clock measures. Some say that what we experience as time is really our experience of the phenomenon of entropy, the second law of thermodynamics. Entropy, loosely explained, is the tendency for things to become disorganized. Hot coffee
Text reads "2019 top 7 visuals." Text is surrounded by pictures that appear in the article.

Top 7 NIST Visuals of 2019

November 25, 2019
Mark Esser
Science, while important, is often thought of as, well, kind of dry in the ocular department. The visuals commonly associated with scientific endeavors are charts and graphs, which are great if you're a scientist, but for the rest of us, they're as inscrutable as a professional poker player's face
graphic showing the number six with a radar dish, a quantum logic clock, arrows representing magnetic spins, a magnifying glass, a baggie of white powder, and a group of cubes in a hexagonal shape

Top 6 NIST News Stories of 2019

November 25, 2019
Mark Esser
Measurement is a subject that touches upon just about everything, from the food we eat and the medicines we take to our investigations of the fundamental phenomena of the universe, so naturally, the news from the National Institute of Standards and Technology (NIST) is widely varied. That’s what
top left: circuit board; top right: materials from HHCIII; bottom left: leaf; bottom right: 3-D atomic clock

Twelve Ways NIST Is Working for You: 2017 Edition

December 29, 2017
Ben P. Stein
As managing editor in the NIST Public Affairs Office, I learn every day how our researchers tackle important societal issues in their work. As 2017 comes to a close, I’d like to share how our news during the last year has connected to many of this year’s current events. Protecting Our First
sundial in NIST Gaithersburg courtyard. The gnomon, several hour markers and the word "time" are visible.

What, Then, Is Time?

November 3, 2017
Chris Oates
When asked to contribute an essay on some aspect of timekeeping, I had a flashback to the first day of my senior year in high school in Princeton, New Jersey. In AP English, we were assigned to write a single paragraph on something, anything in motion. I made the somewhat curious—and possibly
Photo of U.S. kilogram masses

7 Ways Measurements Help You Get Around

May 19, 2017
Fran Webber
With International Firefighters’ Day behind us and World Turtle Day looming, you might not think you’ve got time for another international day in May. But don’t skip World Metrology Day, which is observed on May 20 every year—the anniversary of the signing of the Treaty of the Meter in 1875. Because
Diagram with blue background and man standing behind rope line

Ideas Whose Time Has Come (and Gone), v. 2017

December 20, 2016
Robin Materese
A catchphrase from a popular reality show goes: “One day you're in. And the next day, you're out.” For the purposes of the show, the host is referencing fashion. But the same could be said about science. With each new discovery or advance, an old theory or idea often becomes obsolete … or at least
Howard Yoon with the NIST standard of spectral irradiance, a bright light, well-calibrated light bulb..

Lighting the Way Toward Better Measurements

January 15, 2016
Howard Yoon
As a physicist who explores ways to measure light more accurately, it should come as no surprise that I’m fascinated by even common optical phenomena that we see all around us. For instance, rainbows occur because light travels through water and air at different speeds and because different colors