So a day to tweak and make the thing work over a decent
I've found that a small bit 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
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.