Day 16: Seismograph
day - and AMAZING PROGRESS. Spent the morning tweaking things - trying
different lengths of steel string to use and trying different kinds of
wire to suspend it in. We found a slab of concrete where we actually got
a reading. What I mean is that on gravely ground the seismograph didn't
respond to us jumping up and down, or dropping things. But on a 1 x 1
m concrete slab in the ground - we got some results! Admittedly - only
a tiny, 1 mm high, 'blip' on our paper - but still a 'blip'.
Funny how excited you can get from these things!
once we got the tiny reading - it meant we could change different variables
and see the effect. Jonathan works much more intensely than I do. We changed
the hefty wire (with heavy metal 'grapple' - that neatly enabled
us to change the length of the wire) - and put in nylon wire. We both
thought it should really help. J almost immediately said it was much better.
"But what's your evidence Jonathan?" I yelped. The results
from brick dropping looked almost identical to me. I still thought it
was a better solution (I'd persuaded him that it was) - but I wanted
to see the effect. But J is the one who produces beautiful machines that
work. Intuition is quite a valuable thing! Then took the seismograph "to
the bridge," to see if we got any readings when cars passed over.
Quite nervous - not so convinced we would see anything. The bridge movements
were up and down but we measure sideways moves.
Kate drove the jeep
over the bridge at speed - and we got a reading! Really pleased! We could
even measure the intervals between cars going over the bridge - as we'd
But a problem - the pen kept drifting off to one side - even off the paper.
It's because the paper just wouldn't lie very level . So we
needed to build something to keep it properly flat.... Really enjoyed
working with Jonathan. We talk through things really well together and
he is so good with practical things. It's a treat to feel we're
both co-ordinating so much. And hopefully making something that works.
He's naturally less optimistic than me but neither of us are really
sure we'll measure the dynamite explosion tomorrow! And what's
happening to the 2 Mikes? Cold and windswept and water sodden on mountain?