H'mm... Did the explosion that left a green stain on a ceiling occur during the oxidation of Ethanol using (Sodium or Potassium) Dichromate? That's what tends to leave green stains on ceilings here at Lancing (where I'm the Chemistry department's technician, remember?), although "normally" the solution just shoots up through the condenser _ during the refluxing stage _ without an explosion.

Some years ago one of the pupils here clandestinely "borrowed" a bottle of Glycerol (i.e. Glycerine) and bottles of the necessary acids for nitrating this: Fortunately (?) a teacher noticed the chemicals stored in his 'pit' BEFORE he actually tried the experiment... But I'm fairly sure that one of the teachers did make some Nitroglycerine, to keep a class interested at the end of term, later on.

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"This was willed where what is willed... can get rather silly."

I did really enjoy my chemistry lessons although our teacher was a very serious minded man and didn't have time to indulge our pyrotechnic longings. Mostly my classmates amused themselves with magnesium ribbon and the application of bunsens to plastics and paper.

My difficulty with the subject was remembering the equations and other theory. I loved practical application, my favourite parts being: watching liquid mercury move around, distillation and oxidation processes and playing with the centrifuge. I did quite like drawing diagrams too.

It was only when an elderly physics teacher had to cover our class one day that we had a mishap. I think we were supposed to be studying Brownian motion with the aid of Bromide (?) gas, anyway the silly duffer released the gas without turning on the fume cupboard ventilators. I actually saw three people leap over their lab benches trying to climb out the windows. It was a memorable day :)



Post Edited (06-11-03 10:54)

Our physics teacher was best. When he bought out the Geiger counter and radioactive sources, he always put the screen between himself and the radioactivity rather than protecting us.

As he said "I have to do this every year, you only see it once" !

Also, there was a great lesson where we floated iron nuts and bolts on mercury. A few drops of mercury fell from the beaker so we started flicking them round the desk playing table football. There was real technique. If you flicked to hard the mercury split into lots of pieces and had to be round up into a decent size ball again.

Happy days...

We also did a 'practical' lesson on Dopplar which involved running round the room making the noise of a police siren, listening to the pitch change as people went past.

mmmm, my favorite chemistry experiment was always thermite reactions:
Mix powdered Al with powdered rust, ignite with a Mg ribbon, it creates liquid iron, yay! Looks like a baby volcano.
Of course, now I'm at university (but not for much longer) we get even more fun things to play with. Our physics dept. here has it's own gas liquifying plant out back. This means that there's always a large supply of liquid nitrogen stored by the stairs, avaliable for pretty much anyone to 'borrow', ahh, labs was always fun when you had nothing to do. now if you'll excuse me, I'm off up to campus with a thermos flask...



.

My personal favourite chemistry experiment involves starting with two biological specimens. You need to combine them at room temperature, but apart form that any circumstances will be fine to the experiment.

Did your school do the Thermit reaction in the usual way, in a crucible sitting in a sand-tray? They've developed a showier version here at Lancing_
1/ Make a hollow in the sand.
2/ Fit a small flower-pot (2" or 3" diameter) into a Tripod, and arrange this so that the hole in the pot's base is over that hollow.
3/ Place a small piece of paper across the hole in the pot's base, fill the pot with Thermit mixture (Iron Oxide & Aluminium powder, 3:1 by weight; made using Iron Oxide that has been thoroughly dried, because otherwise the reaction is likely to fizzle...) and pack this well down.
4/ Make a small hollow in the top of the Thermit mixture, and fill this with a suitable 'Fuse mixture' (usually Barium Peroxide & Magnesium powder, 17:2 by weight). Insert a length of Magnesium ribbon into this, as the primary fuse, or use a suitable substitute... A 'sparkler' with its handle trimmed off should work.
5/ Position one or more tranparent safety-screens around the apparatus.
6/ Light the fuse (or, alternatively, the very vigorous reaction between Potassium Manganate (VII) and (dried) Glycerol _ which produces lots of lovely Lilac-coloured sparks & smoke, as well as the necessary heat _ can be demonstrated here).
7/ Reaction goes well (if it's been set up properly), white-hot molten Iron burns through the paper at the pot's base and pours down into the hollow in the sand where it slowly cools.

(Optional stages)
8/ Teacher demonstrating this process during an "Open Day" realises that when he sent the technician who was setting the apparatus up off to get something they hadn't yet made a hollow in the sand as he'd carelessly assumed: White-hot molten Iron runs across the surface of the sand, melts a hole through the side of the metal sand-tray, sets fire not only to the wooden bench but also to the nearest (Polycarbonate) plastic safety-screen as well.
9/ Somebody smothers the fires, using a sand-bucket & a fire-blanket.
10/ Teacher realises that one of the pupils' parents who was attending the 'Open Day' has recorded the incident with their video camera.
11/ When things have been cooled down enough to be cleared away the technician scrapes the charcoal out of the burned area, to reveal a crater that's about 1/2" deep and nearly a foot wide.
12/ Whenever that teacher demonstrates this reaction again his pupils ask him to do so in the same way as on that occasion.

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"This was willed where what is willed... can get rather silly."

We had an 'interesting' version of the phosphorous demonstration.

Usually, a small amount of phosphorous is picked out of the oil using tweezers. An even smaller bit is cut off and allowed to smoulder harmlessly on an asbestos mat. Thus showing some things combust in air (and react with water) so have to be kept securely.

Our version:
1, Teacher gets quite large amount of phosphorous.
2, As he attempts to cut a slither off the main chunk goes pinging across the desk.
3, Frantic attempts to retrieve phosphorous lead to it getting split into further pieces.
4, First piece is now burning merrily on desk.
5, Fire alarm goes off.
6, Whole building has to be evacuated.
7, Very little of teacher's desk left when firemen have extinguished everything.

Thus demonstrating more than adequately that phosphorous can be dangerous !

Simon: I guess you don't use asbestos mat now either.

Nope, we use mats made from a substitute material based on Calcium Silicate... but there have been murmurings about banning that, too.

Do you know an experiment called "the Lasaigne Fusions", which is for finding out which elements (apart from Carbon, Hydrogen, & Oxygen) are present in an organic compound? The correct procedure involves_
1/ Heating a sample of the compound with a small amount of Sodium, in a boiling tube, until they've reacted together fully.
2/ Dropping the tube into a large bowl of cold water, so that thermal shock (due to the resultant sudden change in temperature) breaks the glass and frees the reaction's products to dissolve.
3/ Testing the resultant solution for halides, nitrates, sulphates, etc...

One of the other people in my A-level Chemistry set (the class idiot, the one who had already tested a Hydrogen generator with a lighted splint to check whether it was working...) dropped his tube into the water BEFORE the reaction between the Sodium and the organic sample had gone very far, so of course the Sodium started to react with the water, instead...
Visualise a large bowl of water, with a film of organic material across its surface which is burning gently: Within it lie the remains of a boiling tube, containing a lump of Sodium which is glowing brightly as it reacts with water; above this a column of water, containing flecks of burning Sodium & organic material, is being lifted by the heat & Hydrogen produced by the larger lump's reaction, and is bending sideways to spill its contents onto the adjacent bench-top.
"So THAT's what a 'Soda Fountain' looks like", I commented at the time.
It was rather spectacular, but did leave a crater in the bench-top.
Kids! Don't try this at home!

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"This was willed where what is willed... can get rather silly."



Post Edited (06-11-03 16:09)

Simon and Rob - Absolutely inspiring tales of chemistry! I think I've pulled a muscle from roflmao.

I'm surprised that the thermit reaction video has never been on one of those 'painful things that happen to people' programmes.

Wow! And I thought we had a dangerous lunatic in our school chemistry group. His activities were mild compared to this catalogue of eyebrow-raisers... you know, melting the ends off test tubes, accidentally starting small fires, that kind of thing. Still, he did do it just about every single lesson, so I guess in his case it was quantity rather than quality. :-)



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That which does not kill us makes us stranger.
(Llewelyn the dragon, Ozy and Millie)

Sarah

I made benzene gas once in organic chemistry, but fortunately we were doing microscale. I was trying to inject air into my sealed tube of Griniard reagent prior to withdrawing the sample, and the seal popped off dumping my reagent in the sink, where it reacted with the water there.

On the other hand, my father, while in High School chemistry, apparently was doing flame tests to identify compounds with a couple other guys. They actually were given metals to do it with (by the time I was in school we just got solutions and loops to dip). So they took a tiny bit of sodium, and held in in the burner. "Looks yellow to me." "I thought it was orange." "It was too fast, I didnt' see it.". So they tried a bigger piece. "Definitely yellow." "Looked blue to me." "That's the burner, you idiot!". So my father took a much larger piece, and held it over the flame. WHOOOOSH! Instinctively, my father threw the piece of flaming sodium into the sink, where it went straight down the drain into the trap.

He claims there was only smoke in the top half of the room.

The most interesting thind I saw in science was when we discovered 'why' we were instructed to double check the fastenings between burner and gas tap.
burner moved, hose popped, three people lost eyebrows, fringes and arm hair.
apparently the more interesting experiments were the ones the art teacher was doing in the back of the horticulture dept...

In cold weather, if the teacher wasn't looking, we would warm the lab up by lighting the gas directly at the taps.

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"This was willed where what is willed... can get rather silly."

Yes, that should warm up the entire neighbourhood once the whole building caught alight.

When I did work experience in some bioresearch labs the favoured method of disposing of dry ice (which came with eenzymes to keep them nice and cool) was to throw the cudes into the sink with hot water and a load of washing liquid. Bubbles a go-go...



PSD

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This is the work of an Italian narco-anarchic collective. Don't bother insulting them, they can't read English anyway.

When I was at university we had 'Dry Ice' supplied for cooling organic chemistry practicals when necessary, and soon discovered that tipping meths onto this would cause it to turn into clouds of "smoke" very quickly.

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"This was willed where what is willed... can get rather silly."

When we were doing Chemistry A Level our teacher used to smoke so during practical lessons he'd tell us what to do and then slope off for a ciggy and a brew, at which point we'd make 'soup'. Basically we'd get all the good stuff out of the fume cupboard and bung it in the sink with some pretty coloured stuff to see what we could make. Much fun and we only nearly killed ourselves once (with some kind of deadly nerve gas that we made)!

Our kid; was that Laval? He was a loony. Mind you name me one teacher at that school who was halfway sane.

I got a B in my Chemistry O Level, and Laval wanted me to take it at A Level, but I thought I'd better quit while I was ahead. I'm quite pleased that I understood nearly everything in this thread, though.



- - -
I am very interested in the Universe. I am specialising in the Universe and everything surrounding it. - E. L. Wisty

No it was Griezyak (or some spelling like like that - he had a beard) I don't recall Laval - he must have left.
I tried to think of a half sane teacher but failed - oh hang on.....Mr Purdy the pottery teacher he was OK but apart from him they were all mental.

Teaching can't be good for anyone's sanity, though!



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That which does not kill us makes us stranger.
(Llewelyn the dragon, Ozy and Millie)

Sarah