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"It's all gone wrong for me"1 - no, not the hungover cry of the ethanol-loving undergraduate, but the familiar wail of another lab cock up.
Mine, sometimes; yours, occasionally; and historic, from time to time.
 
1 Bill Bailey, 2001

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Archive for October, 2013

Do you know what happens if you put metal in an x-ray diffractometer? If the beam strikes the metal the whole machine could overheat. Thousands of pounds worth of equipment fizzled out in a shot.

But it still seemed worth the risk.

I was in Oxford, downstairs in the Chemical Research Laboratory, and Amber helped me carefully mount my engagement ring and align the beam to strike the diamond. Her first question was whether I thought my fiancé might have bought me a fake diamond and was checking up on him, and she wasn't the first person to ask me that. But in fact the opposite was true. If I hadn't thought the diamonds were real, I would have had no motivation to see their diffraction pattern. I am a doer: I can't just exist, I have to act, so when I was given my beautiful engagement ring, I couldn't just leave it alone on my finger. I had to do something with it: I had to explore it.

We switched on the diffractometer... and waited... The beam struck the stone, the x-rays diffracted, and very slowly this beautiful, simple, but slightly frayed-looking diffraction pattern began to form.


http://static.smallworldlabs.com/myrsc/user_content/photos/000/029/29634/21d04e1005c6e20af815c987febbefe2-original-img_0096.jpg
[Photo courtesy of Amber Thompson, Oxford]

Posted by Rowena Fletcher-Wood on Oct 26, 2013 1:33 PM BST

Today I have been making fused beads. I have made a lot of fused beads lately and I'm reminded how blaise we have become working at extremely high temperatures. Nowadays, the 1050 degrees centigrade furnace we used to melt the flux into glass is unexciting and we feel no sense of fear or trepidation using it, even when reinforced safety rules are in place, like making fused beads a two-person operation.

We just go 1050ºC? Meh, that's not very much. The blow torch gets hotter than that when you shape glassware. Sometimes we run reactions at 1200ºC (but not very often).

They say once burnt twice shy, but in fact the opposite occurs. After you have burnt yourself a dozen or so times you learn that you can live with the consequences of making a mistake... and stop fretting over it. And that means that even when you are swirling molten glass around you never really concern yourself with the possibility of spilling it and that kind of burn being much, much worse.

Don't worry... that's not where I'm going with this.

We were reminded of how insignificant 1050ºC has become when we needed to do a different reaction at 1500ºC. A colleague of mine put a crucible very like our fused bead crucible into a furnace and left it to ramp up to 1500ºC. Once it was up, we went to retrieve it. Normally when you're making fused beads you have one person open the door and the other takes out the crucible with a very long pair of tongs. A heatproof brick sits at the side of the furnace to rest the crucible on whilst it cools. We set up our brick, got our gloves and tongs, and went up to the lab. We opened the door of the furnace.

And it was literally like looking into the sun.

Whilst the 1050ºC furnace emits a reddish glow, a 1500ºC furnace emits a powerful white light. We hesitated for a moment... then closed the furnace door. Suddenly we were faced with an unexpected situation – 1500ºC is actually very hot. It was hotter than the range of “hot” we were normally used to dealing with, and we were going to have to introduce extra safety precautions. Using the blow torch there are some tinted goggles, and I also knew there were some face shields kept in the same lab, the kind you would use for welding. So we fetched two face shields, put them on and went back to the furnace.

Opening the door wearing tinted face shields, the inside of the furnace didn't look like the sun any more. It looked reddish and glowing like the 1050ºC furnace. We got the crucible out, shut the door, turned off the furnace and removed our face masks. The platinum crucible was glowing red around its base, a clear indication of its ertwhile environment. Just in case we were beginning to forget.

Posted by Rowena Fletcher-Wood on Oct 16, 2013 9:51 AM BST

I once wrote a murder mystery game where the killer committed the act by filling a sealed room with bromine gas. I'm not entirely sure it would work, but once when I was in school the physics class removed itself to a chemistry lab to watch a demonstration on gas mechanics, and we used bromine.

“I have to warn you now,” the teacher said, “that bromine is toxic, although we have a very small quantity here, it can still be harmful, especially to the boys in the room, as it can cause male infertility.” A few teenaged boys shuffled uncomfortably. “So,” the teacher continued, “it is my responsibility to tell you that in case of accident, we must all evacuate the room, okay?”

We nodded, reassured that some safety measure was in place, and that it wasn't anything too drastic.

He then went on to outline the experiment. First, he would expose the bromine gas to an “empty” flask and we would time how long it took to diffuse through and look roughly mixed. We were using bromine, he explained, in spite of its hazards, because it was brown, and thus we could see it. This seemed sensible. In our second experiment, we would expose the bromine to a vacuum, whereupon we would see how fast a gas really travels, when it is unencumbered by collisions with other gas molecules!

We completed the first experiment. Obviously it was the less thrilling of the two, and we looked forward to the second, where the gas would shoot through the flask with the promised velocity and we could ooh and ahh appreciably before going back to the physics classroom and doing the maths.

He prepared the second experiment. He opened the valve between the bromine chamber and the vacuum...



“Ah,” he said.

Then, “So now, we shall all vacate the laboratory.”

And there was as sudden mad scramble as all the boys made for the door like bullets.

Posted by Rowena Fletcher-Wood on Oct 2, 2013 3:31 PM BST