Nov. 12, 2010

Science Dad on Daylight Saving Time

by Vince Harriman

I don’t know about you, but we still haven’t adjusted to Daylight Saving Time around here. Rowan, two and half, now gets up at 5:45 and tries to find a playmate. Beckett, almost six, and the budding scientist in the house, isn’t sleeping any better. He wanted to know why we have to change the clocks back in the first place. While I’m not a scientist, I’ve always had a keen interest in science. And with a budding scientist in the house (and another, no doubt following in his big brother’s footsteps), I get a science question almost every day. So when Beckett asked why we have Daylight Saving Time, I thought I could take a shot at an explanation. While Daylight Saving Time was fairly easy to explain -- more history than science, starting with Benjamin Franklin and ending with the 2007 decision to push DST past Halloween -- explaining why there are seasons took just a little bit longer.

Beckett and I headed for the living room with two oranges and a lamp with the shade removed. I drew an equator around both oranges, placed dots for our location, and stuck toothpicks in each end to indicate the North and South poles.

I then held an orange near the lamp inclining the orange to roughly 23.5 degrees. I spun the orange in place to show the difference between day and night. Next I had Beckett hold both oranges at the 23.5 degree angle on opposite sides of the lamp. With the oranges inclined, it was easy to see the difference in the amount of daylight the earth received in summer versus the winter.

Finally, I encouraged Beckett to walk around the lamp, being sure to keep the orange (earth) at a constant inclination relative to the lamp (sun) so that he could see the days get longer. He could see that the amount of sunlight was far greater in the Northern hemisphere in summer -- and that the amount of sunlight in winter was far less. We finished our discussion by going back to Benjamin Franklin and farming and the need for more usable daylight before in the days before electricity.

My wife watched from a safe distance without saying anything. I had Beckett go through the whole thing in his own words before sending him up to bed. "I still don’t get it," she said.

I think it makes sense, and Beckett thinks it makes sense. Do you think it makes sense?

Science Dad, AKA Vince Harriman, is a freelance writer living in Annapolis. His two sons, Beckett-5 1/2 and Rowan-2 1/2 ask him 'why' approximately 6,341 times a day.

About Vince Harriman

Science Dad, AKA Vince Harriman, is a freelance writer living in Annapolis. His two sons, Beckett-6 and Rowan-2 1/2 ask him 'why' approximately 6,542 times a day.

The views expressed are those of the author and are not necessarily those of Science Friday.

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