Day 16: Seismograph

Another beautiful 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!

So 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 hoped.
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?

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