An Hour Here, an Hour There

By Science Buddies on November 3, 2009 11:54 AM

Does it take you a bit of time to settle in once the time changes? Did you or members of your family wake up earlier the day after the time changed? Do you notice already the changes in available light during the day? Do you know "why" the time changes? Did we gain an hour or lose an hour? Aren't there just 24 hours... regardless?

It's interesting to note that while observing Daylight Savings Time is not mandatory in the United States (and not even all states participate), Daylight Savings Time is regulated by the Department of Transportation. For a look at the history of Daylight Savings Time and its connection to "travel," see National Geographic's "Daylight Savings Time 2009: When and Why We Fall Back."

The end of Daylight Savings Time last weekend and the changing of clocks "back" an hour may have generated some buzz in the teacher's lounge and in the hallways. But, whether the clocks move forwards or backwards, there are still 24 hours in the day.

Right?

The "A Matter of Time" Science Buddies Project Idea calls into question the assumption that "a day is a day is a day." The project introduces students to several systems of timekeeping used around the world: Standard Time, Sidereal Time, and Solar Time. Are all of them equally accurate? The project uses an online tool to help track and assess the accuracy of time depending on which system of measurement is used. Variations of the project can be used to consider issues related to Daylight Savings Time and Lunar Time.

After drawing conclusions about how many hours there really are in a day, the change in time and the ways in which we react to the change leads nicely to introductory discussions of Circadian Cycles, in humans and in other life forms. The following long-term Science Buddies' project ideas explore patterns of response to the time of day (or to light and dark):