Truman suspects that bright light in the sky may not actually be the sun. What if instead of millions of kilometers away, it is merely hundreds of meters up and attached to an invisible ceiling 'sky'?
He devises a shadow measuring experiment.
He stands a 1 meter stick and a 2 meter stick up vertically next to each other.
The 1 meter stick casts a shadow 3.46 meters long but the 2 meter stick casts a shadow 6.94 meters long. That's more than twice as long!
How high and far is the 'sun'?
I was demonstrating the shadow method and similar triangles to find the height of an object. (Give the length of its shadow together with the shadow of a different object of known height.) This works fine outside, but it was the dead of winter. Too cold. Snow on the ground. Cloudy days. It would have been too hard.
So I dug out an old overhead projector and pointed it down. Artificial sun!
We were able to fake it but an astute student noticed the problem. I modified it to make it more interesting.
Posted by Jer
on 2018-03-02 11:16:58