Mountain Video Diaries: Jonathan

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The challenge here is to make glass from sand, which is just a wonderful, wonderful challenge because humans have been using glass for thousands of years and been able to do this magic transformation, to take the sand and get the beautiful glass. So it was lovely to be able to help Mike basically do this chemical challenge.

So my part of the whole project really was to make a furnace to try and heat the sand to get the temperatures high enough, and what I didn’t know when we first started was that not only do you need to get quite high temperatures but you need to have these temperatures for a long time because Mike’s going to prepare the sand, he’s going to add chemicals to it, and when you heat the sand it produces gases, carbon dioxide for example, so you’ve got lots of little bubbles in the glass.

So it’s not just good enough heating it and melting it, because you end up with a glass with loads of bubbles in. You have to heat it for a long time, and I didn’t know about this so when I started on it I was sort of fairly confident that I was going to get the temperatures perhaps we needed, although it was quite high temperatures. But then when I knew it had to be done for a long time, that was the different thing altogether.

So the way I chose was to use an electrical oven. So basically using wire and using the resistance of the wire to put electricity through the wire and the resistance produces heat. And so by making a sort of heatproof container, we used a flowerpot because basically they’re fired at very high temperatures so they can withstand the temperatures. Then we can make a little wire oven, put electricity on it, heat it to very high temperatures and try and melt the sand in this way.

And because I was starting from scratch basically, I had no idea quite how much wire to use, how much electricity to use, whether it was going to burn out after half an hour or whether it would never get to a hot enough temperature. So it was really trying it and seeing it.

So the obvious thing was to take different materials that melt at different temperatures to try it out. So the first thing I think we tried was lead, solder. So we put lead in the oven, wired it all up, and were able to melt lead. Big deal, I mean lead doesn’t melt at a very high temperature. Then we tried aluminium, we tried other metals, slowly getting higher in temperature and we were able to melt aluminium which is halfway to glass, but after that I wasn’t able to do it with confidence really. So when we put the glass in I really didn’t know what temperature we were getting at.

So what we had was basically the bottom of a flowerpot with a little wire element made out of the resistance wire that we could wire onto the mains. 110v in America so it’s a bit safer than the UK, and that would glow red-hot, and then we put a lid on top which is insulated to keep the heat in. And then before we put the lid on we put a little crucible with some of Mike’s sand.

And the first time we tried it, I’d either forgotten or I just didn’t appreciate that Mike not only washed the sand and prepared it but also added a little bit of cobalt. So the sand went in white, we heated it for several hours, I took the lid off and, lo and behold, the cobalt had done its magic trick because the cobalt makes the glass go blue. So I was expecting perhaps a white mess or maybe just white sand, and I took it off and there were these beautiful blue discs. It was an absolutely wonderful moment. It was one of the nicest things I’ve ever seen in Rough Science, just to take the lid off and see these beautiful glass discs.

So we were delighted, and then I went and dropped the lid on the top and broke them which was an awful moment. But it did make us realise that the glass we’d made, a) it was full of bubbles so you couldn’t see through it, and b) it was stuck to the crucible so it wouldn’t have been any use anyway. But it would have been a nice souvenir to take home.

But we learnt a lot from that and so on the subsequent tries we had better crucibles, we controlled the electricity a bit more and we made more material. And so we got to a stage where we were able to not only make lots of blue glass, which was fantastic, but perhaps we might be able to heat it enough to get it so that it was a liquid to pour into the things that we wanted the spectacles to be made out of.

Of course time was running out because we had to develop everything. Mike had to develop the chemistry for it, I had to develop the electrical oven, so because it took time to heat these things time was just running out. So our last attempt, we’d managed to make the glass and it was just like incredibly sticky glue. You couldn’t really pour it out, we had to literally try and drag the thing out with a metal screwdriver, and then ram it into the spectacle lens, the things we made to hold the lenses.

And then by heating it with a blowtorch we were able to just melt it a tiny bit enough, and then we were able to polish it and we made two little discs, with beautiful blue glass you couldn’t see through very well. It was great fun.