Thursday, November 3, 2011


I once again seem to have an awful lot of work to do, was hoping to avoid taking it home with me at the weekend but that's definitely not going to happen so I thought this would be an appropriate time to update here!

Nothing of any great excitement has really happened to me since the last time I wrote, and I shan't bore you with the details of my week - what I want to talk about is the Thunder and Lightening public lecture that was held in the chemistry department last night.

It wasn't anything to do with thunder and lightening, but an excuse for a couple of people from the department to set things on fire and make some loud bangs! Many of the demonstrations I'd seen before, on numerous occasions (although they still haven't lost their appeal), and some were new to me!

The lecture began in a nice relaxing manner with the classic luminol/hydrogen peroxide combination, and various other luminescent type reactions. Even this was enough to get the kids in the audience excited. Very quickly things ramped up - the burning of sugar (lovely smell of caramel!), and then burning more sugar, but this time with some Potassium Perchlorate to add some oxygen and spice it up a bit, same chemistry as the "Screaming Jelly Baby" but this was done on a slightly bigger scale!

It wasn't long until they broke out the liquid oxygen and the patented (maybe) "match on a stick", as well as some cotton wool, my friend and I knew exactly what was coming but were still amused by people waiting in the wings with the fire extinguishers!

There were a few more reactions, mainly involving fire, but we'd seen them before - although the giant barking dog still made me jump! There was also the making of "firework type devices" because legally they can't show us how to make fireworks...

Then it was onto the explosives! This had been done in a guest lecture type thing last year, but I wasn't there so all new to me. The effect of surface area on reaction rate was demonstrated by setting fire to some home made gun powder, and then to commercial gun powder (see - educational really!). There was the exploding of a tin can due to the build up of pressure from heat - that was quite a loud bang, although didn't make another dent in the ceiling next to the one from last year!

Next was a delicate set up. Spread out at the front were 3 bricks, each had a small pile of our old favourite potassium perchlorate on. Onto this was put a liberal helping of white phosphorous (disolved in something sulphur-y!), this was left while he did the next experiment, as it can start itself going. It didn't. Was expecting to be let down as they heated up some copper pipe to initiate the reaction. I can safely say I was not let down. Wow. They were the 3 loudest bangs I have ever heard (why did we sit near the front?!), there was an impressive amount of damage to the aluminium plates the mini explosions were one, but more impressive was the fact the final one managed to split a brick entirely in 2!

After that came the guns, he showed us a few different types of gun - and just how powerful it can be firing even "soft" things. This meant more impressive bangs (although perhaps slightly less exciting as you don't get to see any fire!). The finale was firing 2 guns which had blanks in, but also had something (didn't catch what) which flashed and burnt as it was fired so it looked a bit more spectacular than the other guns being fired!

That was it - my friend and I left the building, ears ringing, hearing not entirely intact (my ears were still hurting this morning!), but very big grins on our faces!

It's nice sometimes to be reminded of the fun aspects of chemistry! Was also really nice seeing the looks on the faces of the non-chemists, particularly the children as various things were being exploded. Hopefully they've been inspired to take up science!

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