Kathy Sykes's diary about the challenge for the Communication programme, from the BBC/OU series Rough Science 4
Day Three
So a day to tweak and make the thing work over a decent distance.
I've found that a small bit of mirror is much, much better than tin foil. Just like in the solar oven, the tin foil (even when polished) has small kinks in that reflect the light all over the place. The mirror is such a good reflector, it means we 'lose' less light.
It turns out that 'losing' the light is our biggest issue. The small reflectors cast such a small light beam that even over only 15 metres we just lose them... we can't see them. The bigger reflectors are better, so even though the smaller tubes produced a bigger response it didn't matter because we couldn't ever 'find' the light beam.
As usual, at the start of the day we thought we'd get it all cracked reasonably easily ... but everything got predictably manic ... and the worst thing happened. It began clouding over and a storm started to brew. Even slight cloud cover affected our device.
It all went crazy, trying to get the plaque, the pen and the device - and all of us - all ready at the same time when the sun happened to shine was nearly impossible. And it was stretching our device to the limit, which made it all the more a joy for everything to work when the sun did shine. We were crazily excited. It just feels a bit magical to have made this thing. The pen worked upside down and Ian's plaque was a beauty.
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Content last updated: 18/07/2006
