On this day in 1918, the United States passed the U.S. Standard Time Act.

Before the invention of the railroad, people used local "sun time" as they traveled across the country. With the coming of the railroad, travel became faster, exacerbating the problems caused by the hundreds of different "sun times." At the instigation of the railroads, for whom scheduling was difficult, the U.S. Standard Time Act was passed, establishing four standard time zones for the continental U.S. On November 18, 1883, the U.S. Naval Observatory began signaling the new time standard.

After learning about different time zones, ask your students to plan a video conference with a class from a different country or from a different time zone in the United States. As they plan, ask students to:

1. Use the World Time Engine to find the best time to schedule this meeting.
2. Research the country or state of the students with whom they will video conference and brainstorm a list of questions and topics for discussion. The place selected can be coordinated with topics they are currently studying.
3. Brainstorm a list of topics about their own town or country that they would like to discuss. Alternatively, they could brainstorm a list of questions they think students from the other time zone might ask them.
4. Use a time zone map to figure out how many time zones they would have to travel through to have this conference if video conferencing hadn't been developed.

If you decide not to carry out an actual video conference, alternatively, divide your class into two groups and allow them to conference with one group playing the role of the class from another time zone.

• A Brief History of Time Zones
  

  BBC News looks at time zones--how they are worked out, why they cause so many arguments, and how they affect us all.

• Today in History: November 18
  

  This page from the Library of Congress' American Memory site offers excellent information and primary documents about the history of standardized time.

• A Walk through Time: The Evolution of Time Measurement through the Ages
  

  Students take a journey from ancient calendars and clocks to modern times, at this NIST Physics Laboratory website.

• The Official U.S. Time
  

  This site provides a clickable map that gives the official time for each time zone in the U.S.