We're supposed to have sun for the rest of the week, but it's never good to take chances with the weather. So, when the sun came out today, we hit the ground running with three solar thermal projects at once.
This time, instead of working with complicated, photovoltaic, solar panels, we experimented with harnessing the heat of the sun to expand air, purify water, and turn a pinwheel. Each project was simple to put together, and provided easily observable results, but with lots of little details that could be tweaked, adjusted, or expanded.
Really I had a hard time deciding which one to write about first, finally settling on the simple solar chimney, or updraft tower we found archived on the National Research Counsel Canada website.
The chimney is made by taping together three, large, empty, clean tin cans, with the tops and bottoms removed.
A wire arch (made from an unbent paper clip) is taped across the opening of the top can...
...with a thumbtack, or straight pin, taped to the center of the arch, pointing up.
The chimney is placed on top of a couple of books, to allow air to flow in from underneath.
Finally a pinwheel - made by cutting diagonally in from the corners of a 6 inch square sheet of paper, to within a quarter inch of the center, bending the every other point from the corners to the center, and taping them in place...
...is balanced on top of the thumbtack, taped side down.
Questions for thought:
Would a paper tower work in place of cans?
Would pinwheels made of different materials, or in different sizes spin faster?
What if the tower was painted black?
Could enough power be generated by the spinning pinwheel to turn a generator?