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River Science: Solar Energy

Solar energy forms the heart of every river ecology; sunlight fosters algae and plant growth, which in turn forms the bottom rung of the ecology's food chain.

To measure solar energy output, we mount a pair of photovoltaic cells in a location that has an unobstructed view of the sky, such as atop the capstan.

We then use an attached voltometer to take regular readings of each cell's electric output over the course of a day, comparing them against each other.

Solar energy output is affected by cloud cover and the height of the sun, as one would expect, so tracking celestial objects plays a central role in these experiments.

Of course, in 1609 Captain Hudson and his crew had no photovoltaic cells on the Half Moon, but they did make use of solar energy in their own way. For example, one of their staple foods was dried cod, and establishing trade for beaver pelts saved the voyage, economically speaking. Both the fish and the pelts were prepared in the same way: by stretching them out on wooden frames to be dried by the sun.

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