Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

HDYMI Credits/Feedback

Project Manager: Robin Materese
Writers*: Alex Boss, Mark Esser, Jonathan Griffin
Editors: Ben P. Stein, Robin Materese
Art: Natasha Hanacek, Brandon Hayes
Video**: Jenny Wang, David Stewart
Web Design: Paul Hernandez
Copy Editing: Sarah Henderson
Science Consultants: Denis Bergeron, Tom Cleary, Sam Ho, Carol Johnson, Jacki Murray, Andrew Novick, Melissa Phillips, Mike Riley, Aaron Urbas, John Wright 


Do you have feedback about this site? Questions you'd like us to answer? Please contact HDYMI editor benjamin.stein [at] (Ben P. Stein). Your question could show up in a future update to this site!

*Writer Credits

Alex Boss

  • How Do You Know Your Food’s Nutrition Label Is Accurate?
  • How Do You Measure the Depth of the Ocean?
  • How Do You Measure the Percentage of Alcohol in Beer, Wine and Other Beverages?

Mark Esser

  • How Do You Measure Your Location Using GPS?
  • How Do You Measure the Age of Things?
  • How Do Smoke Alarms Detect Fires?
  • How Do You Measure the Thrust of a Rocket Engine?
  • How Do You Measure the Performance of Body Armor?
  • How Do We Measure Time?

Jonathan Griffin

  • How Do You Detect Carbon Monoxide?​​​​

** Video Credits

David Stewart

  • Ballistics Testing at NIST

Jenny Wang

  • What is PNT?
    Created March 26, 2021, Updated November 4, 2021