Monday, October 22, 2012

Measuring the Voltage of the Sun | Biology

Well, in a sense.

Before photosynthesis became a hot(!) topic in Elaine Middleman's biology class, she wanted to use solar cells as a way to show how energy from sun light can be converted to another form of energy. When Elaine approached us at the beginning of the year with this objective though, we didn't have any immediately great ideas on how we can plan such a lesson...mostly because none of us knew very much about solar cells at the time.

But we wouldn't let that stop us, of course! After spending some quality time learning about solar cells, we started looking for a source for them. Our go-to electronics shop sold these grab bags of chipped solar cells, but those turned out to be too rough and not ideal for a short one-class activity. Since class time is precious, we needed a more robust solution so we don't risk wasting time troubleshooting broken cells.

Luckily, it turns out there's a big market for solar cells for educational purposes, so we ordered a batch from Lego Education. (Since then, we've also found that there are other places with a larger variety of cells.) We also came upon some old-school, analog voltmeter panels for hooking up to the cells. Once all our supplies came, it didn't take Diego very long to design a box to hold everything together, so the students can assemble DIY "solar meters".

After assembly, the students took their devices around campus to take measurements of how voltage varies in sunny spots versus shady groves versus indoors. Unluckily for the period 2 girls though, the activity ended up on a rainy day! To give them some variations in lighting without having to go out in the rain, Hong dug through his tool chest and brought out his super bright work lamp (which surprisingly got pretty close to the voltage reading of direct sun).

So if you are curious about the "voltage of the sun," just ask one of the girls in Dr. Middleman's class.  Or better yet, try making your own "solar meter"!

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