If it doesn’t work …

Learning Outcome 6 in Physical World of the new Science course is

Students should be able explain energy conservation and analyse processes in terms of energy changes and dissipation.

I had already discussed with the class why a ball does not bounce as high after the each bounce and we had introduced the word dissipation. The class seemed comfortable with the idea of some of the energy changing into other forms that weren’t necessarily useful.

I recently saw this article talking about a new type of solar panel with record breaking efficiency, a whopping 26%!

I decided to build a class around this news story. If I do say so myself it was a brilliant idea.

There are a large number of light/lux meters available for free on both app stores, they give a reading based on the light falling on the lens of the camera.

My brilliant idea was to make a circuit out of a solar panel and a bulb. We would measure the light falling on the solar panel and then measure the light being emitted by the bulb and discuss what was happening, where the energy conversions were happening, the dissipation of the energy. And actually calculate efficiency. I’ve been using the words qualitative and quantitative since September and wanted to do a decent experiment that gave us some numbers.

Nice and simple and hopefully easily completed and understood by the students.

I was so confident that I didn’t actually try it out myself first.

I know, I know.

I got all the equipment, sketched the circuit that students would be using and a couple of them downloaded the app.

You can probably see where this is going. None of the circuits produced any light at all, even when we went outside into blazing sunshine. Nothing.

If it doesn’t work it’s Physics ­čÖü

But to be fair the kids were very good, they quickly set about trying different solar cells, different leads and different bulbs. Eventually one student got the tiniest glow from his bulb, definitely not enough to measure with the app.

So in the end I took a fantastic idea and implemented it fairly poorly.

A learning experience for me as well as the students.

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