US Time Zones | Overview & History

United States Time Zones Activity

How did trains standardize time in the United States? - William Heuisler

How do people around the world keep time together? They use atomic clocks. These remarkable devices tap into frequencies hidden in the hearts of atoms to produce astoundingly stable, accurate ticks of time – far better than any other kind of clock. This animation explains why we use atoms to keep time and how they keep us all on the beat. | National Institute of Standards and Technology (NIST)

Atomic Model Timeline

Sharp Atomic Desktop Clock – Auto Set Digital Alarm Clock - Atomic Accuracy - Easy to Read Screen with Time/Date/Temperature Display- Perfect for Nightstand or Desk

Daylight saving time: NY waiting on these 5 states to make it permanent

19 states approved permanent daylight saving time. Why they still have to change their clocks

The Hill's Headlines u2014 March 7, 2026