We told him that it would be better if he not mark up the bathroom wall; if he really wanted to do this little experiment, we told him to tape paper to the wall and mark the paper instead. Then we told Marc about sundials, and how they told people the time before the age of watches. This piqued his curiosity, and so in a few minutes we were searching the internet for instructions on making a sundial.
We needed just a few tools to make this temporary sundial: A ruler, a protractor, a pen, a marker, and a knife. We decided to make our first sundial out of cardboard.
Here Marc is cutting out the base piece from some leftover cardboard.
We traced the protractor onto another piece of cardboard, and then determined a 32 degree angle. i cut the gnomon out of the cardboard.
The next step was to mark the hours on the base of the sundial. We traced them on this piece of cardboard, and Marc labeled the hours from 6 a.m. to 6 p.m.
What did we do wrong? After moving the base around, making sure there were no large metal deposits below us, and switching from the 'True North' and 'Magnetic North' settings, I figured it was the Sun's fault. Maybe it was the Earth's fault. Global warming certainly had something to do with it.
After a while, I started thinking that the sheet we used to trace the hour lines was from a website based in England. I suspect I shall have to go online and figure out how to calculate the 'hour' lines for our home in North Texas. I shall put on an update about this after I investigate it further.
Still, this was a cool thing to do with the children when I should have been sleeping after a night on call.