The Science of Daylight Savings

Hopefully everyone reading this turned back their clocks 1 hour this past Sunday morning at 2 AM (except those in Arizona and Hawaii).  If not, you made it to work an hour early.  Congratulations, now you can catch up on all the work you didn't get done last Friday!  :-)  While waiting for the bus with my daughter this past Monday morning, it was a great opportunity to talk to her about daylight savings.  I asked her, "What looks different this morning?"  She noticed immediately that it wasn't so dark outside.  You could see the other houses and trees across the street.  At that point I explained that in November we turn our clocks back 1 hour, and in March we'll turn them ahead one hour.  As a result, in November, it's lighter out in the morning and in the evening it gets darker earlier.

The official dates are the first Sunday in November and the first Sunday in March (2 AM Sunday for both).  Until 2005/2006 the date was earlier in the Fall and later in the Spring.  There are two states that do not follow daylight savings time:  Arizona and Hawaii.  Until 2005, Indiana was part of that group too.  So the big question is this:  Why do we celebrate daylight savings?  

The historical reason is that it saves on energy costs.  A 1970 study by the U.S. Department of Transportation concluded that energy costs are cut by 1% by shifting our clocks an hour twice a year.  One percent may not seem like a lot, but it adds up over millions of people.  Recent studies, however, conclude that it is a wash.  Energy may be saved in the winter, but air conditioners run longer in the summer.  Today I'm not sure that there's a strong argument that daylights savings is necessary.  Personally I could care less whether it's continued or discontinued.  But it did offer a good daddy/daughter science moment.