MeasuringYourLatitude
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(Renamed from MeasureLatitude)
I mention every now and again that at Equinox and the Solstices, my wife and I go out to the sundial in the middle of the village and measure our Latitude. It's just a bit of fun, and it's not very accurate, but it's been a starting point for more than one interesting conversation with random passers-by.
So here's what we do.
We take with us some sort of stand ... a tripod, or even just a director's chair ... and we hang a weight on a string from the back of it to make a pendulum.
Then for an hour or so, starting half an hour or so before local noon, we put a penny on the ground at the end of the shadow of the top of the pendulum. Those pennies fall more-or-less on a straight line. (Technically it will be a conic)
We put a penny on the ground under the pendulum to mark its location, and when the hour is up we find the shortest distance from that penny to the line of pennies. That's the shortest shadow, which was at local noon.
Now measure the height of the pendulum ... call it H ... and the length of the shadow ... call it L.
The pendulum and its shadow form a right angle, so we can compute the appropriate angle with arctan(L/H).
At Equinox, that's your Latitude. If you do it at both the Solstices and take their average, then you get your Latitude, and the difference between that average and either of the extrema is the Earth's axial tilt.
There are refinements, but broadly, that's the approach.
It's not hard to get close, it's harder to make it really accurate, but thinking up refinements and computing error margins is half the fun.
One of the LongStories (sort of)
Backlinks: LongStories MeasureLatitude