Tuesday, June 21, 2016

A Young Scientist and a Solstice

June 21 is typically considered to be the summer solstice (for some reason this year it was June 20). And 50 years ago on this day, this budding young scientist (age 9) decided he wanted to calculate the latitude of Lindsay, California, where he was growing up.

It was quite simple, really. On this day each year the sun is directly overhead at the Tropic of Cancer, about 23 and a half degrees north latitude. Therefore all I had to do was measure the length of a shadow cast by a vertical stick and do some simple trigonometry, and I was able to calculate how many degrees north of the Tropic we were. In order to get the vertical stick, I used a broken arrow embedded in mud, and used a protractor to make sure it was vertical. I had to do this precisely at midday, of course. I seem to recall my answer was pretty close to the latitude shown on the map.

This was an exciting thing for a nine-year-old boy. It was one of my earliest moments as a scientist. I was putting my faith into action: faith that the universe followed natural laws, and faith that humans could learn truths about the universe by measurement and calculation. This is exactly the kind of faith, and the kind of curiosity, we should encourage in children.

By the way, “solstice” comes from “sol,” the sun, and “stasis,” unmoving. The solstice is the day on which the sun appears to stop moving and reverse its direction, as viewed from the Earth.

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