Understanding Time & Gravity

We doubt even physicists really understand how time and gravity work. These sites, however, give you a glimpse into it all, appropriate for students.

Like other resources in this library, these sites advance the traditional curriculum by asking meta-questions: Who sets the time on our globe? How was the time set in history? What is global time (rather than a student’s local time)? In other words, students can go beyond the descriptive to the analytical.

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A Walk Through Time - Ancient Calendars

This on-line essay on the history of timekeeping was conceived and written by Kent Higgins and illustrated by Darwin Miner, of the Program Information Office of the National Bureau of Standards (now NIST). Originally penned in 1975, it has been updated numerous times over the years.  learn more

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Does Time Really Flow? New Clues Come From a Century-Old Approach to Math

Strangely, although we feel as if we sweep through time on the knife-edge between the fixed past and the open future, that edge – the present – appears nowhere in the existing laws of physics. Albert Einstein wrote in 1955, "... the distinction between past, present and future is only a stubbornly persistent illusion." And…  learn more

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EarthSky: What Is Time?

Thomas Kitching, a cosmologist and astrophysics lecturer, looks at questions like: Does time have a beginning? Time's arrow? Will time end? Written in non-technical language, this post gives you an idea of the questions scientists are looking at.  learn more

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How Gravity Makes Things Fall

A demonstration of gravity, featuring the "Spacetime Stretcher," built mostly out of materials from the garage and hardware store. Click on the YouTube logo to view the About section containing additional details. Would make a great classroom or science fair project.  learn more

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Major concepts and a history of time-keeping can be found at the NIST site.  learn more

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Strangest Time Zones of the World

This video looks at some of the world's strangest time zones, including: China, Kiribati, Nepal, Australia and more.  learn more

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Telling Time for Young Children

There are a number of videos helping kids learn to tell time. This is one of our favorites.  learn more

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Time Zones

This site provides an overview of Time Zones, what are they and why we have so many of them. Who knew the International Date Line created 3 extra time zones.  learn more