'I knew the company was doomed after managers brawled in a biker bar' Welcome again to On-Call,The Register's regular... hang on, isn't On-Call a Friday thing? Why yes it is, but in the week before Christmas there's so little news around we need something to run on the site. And it's only fair that we empty out the On-Call mailbag, which is full of fine stories that aren't quite enough to …
They will be monster sharks with huge chemical lasers.
Bezos will just have millions of normal sharks with tasers* attached. My money, laughable though it is, will be on Bezos.
*Yeah I know. The physics don't add up whilst the sharks live in salt water but if that is what you focussed on - you realise that you still WENT TOO FAR down this rabbit hole.
It is a VERY bad idea to secure the lid on a LN2 flask except during temporary transport. Otherwise what you will have is a bomb. The LN2 will slowly vaporise, raising the pressure and the temperature meaning more will vaporise and the pressure will continue to build until the structure of the flask (lined in glass remember) fails.
In Biology we use it for fast freezing things, very useful stuff. And we instruct every naive student/postdoc in how to do so safely. When dispensing you must wear cryo gloves and the face mask (think wood turning).
When we have finished with our LN2 we simply leave it on the bench with the top off to vaporise in safety.
When dispensing you must wear cryo gloves and the face mask (think wood turning).
Think I'm showing either my age or my university's lax attitude to the welfare of its students, but at the time the only requirement was to make sure the room was ventilated* and gloves were forbidden (the risk being, apparently, that momentary contact with skin wouldn't do any harm due to the insulating effect of the gas, but if it fell between a glove and the skin it'd cause nasty burns).
* I'm almost certain they found this out the hard way.
that momentary contact with skin wouldn't do any harm due to the insulating effect of the gas
Concur - wearing gloves is a risk in itself. If it gets into the glove you are royally screwed. You are better off to use a trivial towel if the handles are too cold. No gloves unless they are at least elbow length ones.
Same here.
I also remember our physics teacher suspending the inside of a Thermos flask in a sort of string cage, filling it with liquid oxygen and then getting the enormous Eclipse horseshoe magnet to show that liquid oxygen is paramagnetic by making the flask move. I sat there thinking how fragile those flasks are, and how sharp contact with the magnet could cause a cascade of LOX all over the bench.
This was the same man who, annoyed by a flickering fluorescent over the bench, climbed on the bench to remove it ignoring the fully charged and operating van der Graaf at one end. Predictably he removed one end of the tube, the other end fell out onto the van der Graaf dome, and the tube lit up. The shock caused him to drop it; it survived. A few seconds later he dusted himself off (chalk in those days) and asked us to explain the phenomenon we had just witnessed. I believe he ended up in charge of the science education at the LEA. Nowadays I suspect he's have been subject to a disciplinary enquiry.
He's the man who caused me to go into science rather than law, I look at my lawyer kid's mini-mansion and my own humble 4 bed detached and I'm not sure what I think of that.
"A few seconds later he dusted himself off (chalk in those days) and asked us to explain the phenomenon we had just witnessed."
In my yoof (O & A levels), I'd have come back with "The four pints at lunch, Sir?" ... I got yelled at a lot as a yoof, but my grades were good enough that I got away with it ... usually.
I was in the 5th form out country pubbing with some mates one weekend. We walked into a favourite pub and there was my form and physics Master sitting in full Morris Man regalia with a pint in his hand, he just nodded to me so I bought him a pint, a favour which he duly returned, he just grinned and said 'Don't I know you from somewhere?'
He was one of the best teachers I ever met, he could teach physics ,chemistry and maths, he was also an Oxford rugby blue and being a Morris Man could drink ale at Olympic level.
Canada, grade 11 and 12 math teacher, who always reeked of cigarette smoke, also worked as a waiter at a local beer parlour.
"Beer parlour" was a 70s term that carried a significantly seedy overtone. A large room with 24" round tables, covered with terry cloth. Beer was commonly drunk with either tomato juice or salt
No entertainment, no hard liquor, just serious drunkenness.
Until the 70s there were separate entrances and areas for "Men" and "Ladies with escorts."
Anyhow, the same math teacher refused to teach or test us on factoring square roots because "there's a table in the back of your book."
He was sacked a few years later fro running a still in the prep room.
One of the boys ahead of me by a year or two did this as a Senior science project. Can't remember if he won or not, but one of the other projects was a relay-logic tic tac toe game with a telephone dial as input.
Gunpowder was frequently made. And a mercury vapor lamp, using an old oil burner ignition transformer, a couple of pieces of copper wire and a pool of mercury. No protective gear needed because we were oblivious of the hazards. As far as I know, we're all still among the living.
// icon seems appropriate
// today, we'd all be in prison. or worse
"Gunpowder was frequently made. "
The VIth form was quite small - so the Science stream used the prep room for their practical work.
One day the senior Science master was teaching in the adjacent lab. A lad came out of the prep room and asked for glycerine off the shelf - which the teacher handed him without a pause. Then a little later he came out and asked for concentrated nitric acid. Again the bottle was handed over without pause. After a few moments the master suddenly stopped stalking - he had made a niggling connection between the requested chemicals and the particular pupil asking for them. Sure enough P** was intent on making nitro-glycerine.
One of our authorised experiments was making nylon. A boy's father arranged for a full size bottle of nitrogen - that was then lashed to the end of the bench. The gas passed through a tube of heated chemicals - and a noxious stream of smoke came from the rubber tube at other end. Quick thinking stuffed the rubber tube down the sink plughole. Problem solved - until the adjacent lab was evacuated with the fumes coming up on every bench's sink through the shared drain.
We never managed to get any nylon out of that experiment.
A chromium compound precipitate was drying nicely in a flask over several days. Then it mysteriously was filled with water. The senior chemistry master knew that when dry it was likely to spontaneously explode.
Also brings to mind my old chemistry teacher (and safety officer) at high school, who also had a penchant for making Nitrogen Tri-Iodide (and the fool taught us how to make it too).
He used to enjoy putting small quantities of it under lab stools, especially when the stool occupant was a girl wearing a long skirt so that the resultant draught when they moved set the stuff off.
Apparently in the year after I left the place he got a little overenthusiastic with how much he used at once, resulting in it going off on the bench in front of him and so I'm told he "came flying backwards through the door to the prep-room in a cloud of purple smoke".
He also enjoyed doing end-of-term "chemistry displays", basically all the kind of experiments that would today be utterly banned under health and safety (and probably terrorism) laws. Nothing quite like the red lead thermite reaction to fill the lab with dense acrid smoke ;)
"Nitrogen Tri-Iodide"
We came into our small office after the Xmas break and noticed the occasional cracking sound as we walked. The floor had been thoroughly washed - but the sodden card tray labels on at floor level suggested some enthusiasm.
Apparently one of our juniors had spread copious amounts of the chemical on the floor. In the darkened building the security guard had seen the floor glowing and applied the fire extinguisher. It was a severe breach of discipline but the junior wasn't sacked.
Back when I was in college a all knowing under grad chem major would mix ammonia and Iodine to produce Amonium Iodide, a low level contact explosive used mainly by students to amuse unsuspecting visitors. One day he set a batch on the windowsill to dry; a breeze came up and scattered the sample over his dorm room, producing unexpected small and occasional larger unexpected explosions until the room was thoroughly cleaned.
In high school the teacher demonstrated the effect of a small amount of adding Phosphorous to a small beaker of water--mainly bubbles, hissing and similar low level effects. This was mildly amusing so the next day a student decided that if a little was amusing, seeing a large amount dumped into a nearby pond would be a most spectacular sight. Unfortunately in haste he grabbed the wrong sample bottle--it was not Phosphorous but Sodium. The most unfortunate part of this episode was that the resulting explosion broke all the windows of the assistant principal's apartment building. The student might still be in the detention room
.... a long, long time ago, in a place far, far away... well, actually at SWCFE we had to come up with a nice pretty experiment to demonstrate at the open day.....
.... needless to say we managed to talk our chemistry lecturer into "donating" a few goon-bags of cheap red wine & spent the day merrily distilling it......
Wasnt until late in the afternoon when one visitor actually asked what it was that we were distilling.... by then none of us cared..... and it all gets very hazy around that time.......
"When I was in the lower VI I once met my Chem teacher in the pub at lunchtime, [...]"
After the Prize Day at a local hall the headmaster would take the platform guests for a drink. A member of staff would discreetly signal which pub they would be using. The rest of the staff then retired to a different pub. The staff used the saloon bar - so they could turn a blind eye to the mostly under-age VIth form boys in the public bar - perfectly visible across the centralised dispensing counters.
"He was sacked a few years later fro running a still in the prep room."
Our school had a legal still in the senior chemistry prep room. Periodically someone from Customs & Excise would make an unannounced visit to check what it was being used for and to remove a sample of product for analysis. I'm surprised they needed a whole litre just to check it was plain ethanol.
When I was in the lower VI I once met my Chem teacher in the pub at lunchtime,
I stayed late after school with the chem lab tech, my best friend, and we're doing some "tests" in the lab. The Chem teacher walks by at one point and asks what we were doing..
"Nitrating glycerne." we responded.
"Oh.. ok.". He suddenly stopped and slowly turned around with this pale look of fear. "What?" And then carefully took the test tube and took it outside. There was a loud "bang" when he tossed it in the field behind the school. Surprisingly, no cops showed up, no neighbors were upset. All we got was "don't ever, ever do that again".
"He's the man who caused me to go into science rather than law"
We had a similar teacher for physics. He used to come up with elaborate but entertaining reasons to smoke in the class room. Diffusion of gases in the air was explained with the help of a cigar and a request to tell him when the pupils at the back of the class room could smell the smoke. Conductivity of heat was demonstated by wrapping a ten pence coin (acquired from the class reprobate) in a lace edged hanky (acquired from the class posh girl). He then stubbed out his lit cigar on the hanky wrapped coin, much to the distress of the hanky's owner. He then unfurled the coin and dropped it into the hand of the class reprobate, who of course got mildly scorched, and proceeded to brush out the superficial ash mark on the otherwise undamaged hanky.
All of this came back to me when I read of the passing of Heinz Wolff ... where's El Reg's obituary for him?
A colleague of mine in the 80s had done National Service in the RAF just after the war. As a rookie tech he was a vital part of the Radar testing regime. His job was to take a flourescent tube and stand in the middle of the airfield. The operators stopped the radar dish sweeping the sky and pointed it at him, if the tube lit up it was working.
"The operators stopped the radar dish sweeping the sky and pointed it at him, if the tube lit up it was working."
In amateur radio we used to hold a small neon bulb near the transmitter output. If it lit up red then everything was ok. If it had touches of purple then their were judged to be spurious parasitic oscillations present.
The 'head of science' at my school seems to have been equally bumbling.
He set up a wave generator (water, not sound), somehow connected it up to AC rather than DC from the multifunction power supply. Then when it a) didn't work and b) started smoking, lunged for it and knocked the whole thing into the basin of water.
While teaching about electricity and transformers, set up a pair of step-up/step-down transformers with a low voltage source and just as he was about to invite us to grab the far end, realised he'd connected one the wrong way round and had actually set up step-up/step-up with the resulting voltage now in 4 figures.
The 'head of science' at my school seems to have been equally bumbling.
One of my science teachers was going to demonstrate that a short-circuited coil wants to enclose as small a magnetic field as possible. For which you take a (conducting) ring, an U-shaped core and an appropriate primary coil. On powering the primary, the ring will fly off its leg of the core.
Which it did.
Smashing two fluorescent tubes, despite those being protected by a physics-classroom-grade mishap protector.
My chemistry teacher once went to demonstrate what a stochiometric mixture is, by filling an empty paint tin with natural gas. The tin has a small hole in the bottom and one in the lid, so that gas escaping from the hole in the lid is replenished with air through the bottom hole.
You light the gas coming out of the hole in the lid, then wait for the gas/air mixture to become stochiometric. At which point the flame will ignite the gas mixture, and the lid will pop off.
Or at least, that's the theory. If you use a small tin and reasonably-sized holes.
In this case, the holes were quite small and the tin, well, one-fifth its size would have been a better choice.
Due to the volume and the small holes, the mixture was slow to reach its kaboom point, so the experiment was put aside to do its thing while other experiments were demonstrated. And with no-one paying much attention any more, the kaboom caused a lot more consternation than it normally would have.
You light the gas coming out of the hole in the lid, then wait for the gas/air mixture to become stochiometric. At which point the flame will ignite the gas mixture, and the lid will pop off.
This, incidentally, is why you should not try to light your farts. There's no lid to pop off...
"Due to the volume and the small holes, the mixture was slow to reach its kaboom point, so the experiment was put aside to do its thing while other experiments were demonstrated."
In other words, you were being shown why you don't put an experiment aside until you're sure the reaction has actually completed.
I nearly took off a science teacher's eyebrows with the sulphur and zinc reaction. Mine studiously failed to go off until he quizzically leaned over it to see what was wrong - and it went off about a minute after it'd been taken off the bunsen.
My secondary school Head of Chemistry used to walk around with a mixture of mercury and iron filings in his lab-coat pocket, and he used to walk behind the pupils and throw pinches of the mixture into the lit bunsen burners on the bench. Very hard to concentrate when a low-grade thermite reaction is going off in front of you!
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We made a 'bomb' in the pub carpark out of a 2 litre Coke bottle and the AI lady's LN2.
Dry ice works as well.
Boy Scout Thanksgiving at the camp. The scouts had the brilliant idea of doing this experiment. Having once been a boy of that age, I knew talking them out of it was futile, so I imparted a few suggestions: throw it out in the middle of the pond, remember that the neck and cap are fairly solid and likely to come whizzing by, so find a friendly tree to shield you...and returned to wait for the inevitable with the rest of the adults.
My son came in, mentioned casually that the neck and cap had come fairly close to his tree, and there was general hilarity and amazement at the volume of the explosion (which was, to be honest, louder than I had expected).
When I discussed this event with the parent of another scout, he mentioned that he and his buddies used to do this with *glass* Coke bottles in a more densely populated location (the loading dock behind a restaurant). Braver than I.
// again, probably terrorism charges today...
For me, it was a 2 liter soda bottle, ~1 square foot of tinfoil, and muratic acid. fold the the tinfoil and slide in the neck of the bottle, add ~2 inches of acid, cap tightly, and throw as far away as you can, and avoid the giant white cloud of gas when it finally blows.
There was some lesson to be learned after that, but I don't rightly remember what it was. (it was an allegory or something- this was a sunday school lesson at the church I used to attend.)
Ah yes. Happened to me whilst measuring the 'magnetic screening properties of a high temperature superconductor'. High Temp, in this case, meant liquid nitrogen. Being undergrads, the kit was all a bit Heath Robinson, including the clamp holding the sample in place. As you might suspect, it fell off once or twice. Only once did I put my hand in (with glove). There was a hole in the thumb (Dear Liza) which promptly filled up. Cue spilled liquid nitrogen all over the desk/floor.
This is when I learned that liquid nitrogen is cheap, so the easiest way was was to pour it out, salvage the sample and start again.
My first encounter with liquid nitrogen was during an open weekend at the Physics dept in Exeter. A group of us walked into one lab, where some prof decided it was fun to pour it all over our feet.
Ah yes, Exeter uni physics department, where, due to a couple of MRI machines, they have their own gas liquification plant out the back. What this meant for us students was effectively unlimited amounts of LN2, stored by the back door in massive dewar flasks.
Of course, as budding scientists we used it to investigate things, eg, can you touch the bottom of a bucket of LN2? (yes you can, if you're quick, and all you get is a slightly chilly hand). Another fun experiment was testing what happens when you freeze the various ingredients in someone's lunch box, with the extension of "what happens when the subject tries to eat their now solid sandwich". Of course, this was best performed under blind conditions, ie we wouldn't tell someone that their entire lunch was now two hundred below...
Sure. Mars Bars. My lab had a burn-in oven, purged using several good sized tanks of LN2. The usual habit was to freeze the candy bars with the LN2 and then slam them down on a bench, resulting in handy sized fragments.
In the old days film for the instant photo head of the macrocamera needed to be coated with a preservative. The preservative would be packed in a one time use sealed tube about the size of your thumb. Load the tube with a few CCs of LN2 and carefully chewed up fragments of paper and place it in an inconspicuous spot. The pressure would build up and eventually the tube lid would pop off with a loud POP and a shower of confetti would fill the air. "Veddy Bootiful" to quote the Three Stooges
"My boss used to say that it cost about the same as milk."
Liquid nitrogen can be cheaper than milk. When liquid nitrogen is delivered in small Dewar flasks it runs about $0.50 per liter, which is reasonably milk-like in price. However, bulk LN2 deliveries by tanker truck are about $0.10-$0.15 per liter.
"Think I'm showing either my age or my university's lax attitude to the welfare of its students, but at the time the only requirement was to make sure the room was ventilated and gloves were forbidden (the risk being, apparently"
I'm with you on this one. In the late '60s - early '70s we had no particular precautions. The supply was a large flask on a tilt stand and was dispensed carefully into the smaller flasks used to chill down some of the cold traps on the carbon dating system. IIRC the University porters brought filled flasks from a larger supply in the Physics Dept. I can't remember about gloves but we probably had them for handling the dry ice which was used for some of the other cold traps.
Well, sweeping fluid ... Take a jug of LN2 and "throw" it along a floor. It'll gather all the bits of dust left by common cleaning equipment, and deposit it in a kind of terminal moraine wherever the liquid settles. We used to use it for secondary cleaning of class 10 clean room floors.
Yup, excellent for floor cleaning.
Also totally true about the gloves comment. If you stick you hand in it and keep it there then you're in trouble, but you can actually "swish" (for want of a better word) your hand through LN2 without issue as long as you're quick and keep it moving. As noted the vapour that forms around your hand insulates it from the liquid and you're fine.
But if you're wearing gloves and it splashes on them, they absorb it and freeze to your skin if you're unlucky. The only cryo-burns I ever had during my PhD years (using LN2 and LHe on a daily basis) were from gloves until I learned that lesson.
Great stuff for getting kids interested in science though. We did a schoolkid lecture every year with all the usual tricks (hammering nails into wood with a banana, shattering rubber tubes and roses, making a metal ball shrink and pass through a ring that it had been sat on at room temperature plus the standard superconducting magnet stuff).
Oh and it's great on hot summer days for making instant ice pops, and of course keeping the place nice and cool with the aid of a small fan.
Fond memories indeed...
"It is a VERY bad idea to secure the lid on a LN2 flask except during temporary transport. Otherwise what you will have is a bomb."
Well, that depends on the lid...
A non gas tight lid is fine, it stops it spilling if accidentally knocked over, reduces losses and doesn't result in a pressure buildup.
However leaving an open dewer in front of a door is genuinely daft...
Dereck Lowe (he of "sand won't save you" fame via his blog "in the pipeline") has some amusing commentary regarding LN2 tanks and what happens when you intentionally disable the safety features:
http://blogs.sciencemag.org/pipeline/archives/2006/03/08/how_not_to_do_it_liquid_nitrogen_tanks
And one for LOX:
http://blogs.sciencemag.org/pipeline/archives/2010/03/10/how_not_to_do_it_liquid_oxygen_cylinders
Oh, come on, lighten up. I was fortunate enough to go to the local equivalent of what in Britain call grammar schools which specialized in sciences (in fact attached at the hip to the local Uni) in the days before H&S and political correctness spoiled everything.
We had the first year physics profile (equivalent of UK year 10) get hold of liquid nitrogen on regular basis and sneak it into the canteen. You DID NOT leave your meal unattended. If you did you could find it in a state where you could break a knife trying to cut a meatball or the spoon was sticking out straight up out of the soup with ice forming on it.
That was one of the more harmless pranks. The chemistry profile the year after me did things like drilling carefully chalk with a compass or the cartridge of a ball point pen, filling it with silver acetylenide and leaving it at the blackboard amidst other chalks and lighting a fuse. A few mg make a relatively harmless bang which will at most bruise a palm if you blow it up in the middle. Lots of noise, little damage. Putting it in the middle of a chalk, however... if done right... You could get a cloud one third the size of the classroom. Hydrogen baloons with lit fuses floating at the ceiling - you name it.
Those were the days... Me coat, the one draped over the zimmer frame.
So it was just a harmless flask sitting somewhere. Not like it was poured into your coffee or something (that one is fun).
in the days before H&S and political correctness spoiled everything
I still remember the name of one my chemistry compatriots who refused to believe that the pencil sharpeners were made from blocks of magnesium and decided to prove us wrong with the help of a bunsen burner. It made a terrible mess of the teacher's desk on the level below. After burning its way through the floor ;)
And making explosives in the chemistry lab was easy. They didn't even keep tabs on the quantities of chemicals used in legitimate classroom activities. Nor were there locks on any of the cabinets. We even had access to real acid, and things like toluene and benzine ... And strangely enough, kids rarely got hurt. Probably because they taught real chemistry back then, not the watered down crap of today.
Then there was the Medicine student in Adelaide who “borrowed” a severed penis from a cadaver, sewed it to his jeans (outside, otherwise right where it “ought” to be) and went for a walk through the town centre.
I reckon the Bill would have had a problem. After all it was not his John Thomas on display. Wasn’t even connected to a living human.
“borrowed” a severed penis from a cadaver, sewed it to his jeans (outside, otherwise right where it “ought” to be)
The version I'd heard was that it was sewn to the botton of the trouser leg, so it bounced on his shoe as if too long to be fully contained.
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We even had access to real acid, and things like toluene and benzine ... And strangely enough, kids rarely got hurt. Probably because they taught real chemistry back then, not the watered down crap of today.
And probably also because the people involved knew that high concentration acids are mildly dangerous and were exceedingly careful when brewing their little conconctions.
It's the same as i'm always cautious when taking things apart that say "DANGER - NO USER SERVICEABLE COMPONENTS INSIDE" to, um service the non user serviceable components. It's potentially dangerous, but as long as your very careful it's fine.
Todays students are used to not handling anything dangerous (because it'd be banned by H&S) and so don't develop caution. After all why should they? They only get allowed to play with acid that's significantly dilated for safety reasons.
"It's the same as i'm always cautious when taking things apart that say "DANGER - NO USER SERVICEABLE COMPONENTS INSIDE""
I was taught, as an equipment designer, to put one securing screw where it could only be undone by removing the IEC plug, and to ensure that it took long enough to unscrew for any capacitors to discharge.
The other approach is to arrange one screw so that it pushes the lever of a microswitch, so as it's undone the mains circuit opens and a second switch closes and discharges a large mains capacitor. OK for ordinary stuff up to 450V or so, but not when your kit is a lightning simulator and it's discharging 10kV from 22uF, which many switches do not like.
At my school the dinner ladies ensured this would happen even without the aid of liquid nitrogen.
The custard at my school was commonly referred to as YellowCake - very, very bright yellow, solid beyond the 'goo' level of bad custard and I am pretty sure that it would glow in the dark.
"very, very bright yellow, solid beyond the 'goo' level of bad custard [...]"
When we stayed after school for various hobby clubs there would be cups of tea available for 1d a cup. It was a bonus when there were also 1d slices of jam tart which had been top filled with yellow custard that had set pretty solid. Things were revolutionary in the 1960s when we started to have pink custard.
you name it.
Our chemistry lab sinks didn't have simple "U-bends" to prevent reflow, they had large plastic pots that could be unscrewed to clean out sediments, so they held a lot of water & air. Drop a sizeable chunk of sodium into one and after a few tens of seconds fizzing the resulant explosion would send a jet of flame several feet long back out the plughole, by which time the culprit was back at his own seat looking innocent. Not much the teacher could do, given his own admission that as a Uni student he'd tipped a 1lb lump of sodium off a bridge into the local river to see what would happen.
We also demonstrated that mains water pressure was higher than mains gas pressure, by connnecting the two taps together. All across the lab, bunsens began to splutter & then emit a jet of water, raining down on the class. Apparently the gas pipes still gurgled years later.
And then there was the nitrogen tri-iodide spread across the desk as a precipitate. Harmless when wet, but once dry even setting a sheet of paper down caused a chain of explosions...
"Drop a sizeable chunk of sodium into one and after a few tens of seconds fizzing the resulant explosion would send a jet of flame several feet long back out the plughole"
One of my chemistry teachers tried something very much like this, except in a canal. Apparently, the police had words because they didn't want the local yoofs getting any ideas about depth-charging the ducks.
"... he'd tipped a 1lb lump of sodium off a bridge into the local river to see what would happen."
Tried that many years ago with some dry ice: v disappointing just produced a few bubbles. Will try to be more ambitious next time :)
"Tried that many years ago with some dry ice: v disappointing just produced a few bubbles."
My chemistry teacher tossed a pound of sodium wrapped in newspaper into the school swimming pool.
The hydrostatic shock cracked the pool so badly it was eventually filled in, concreted over and turned into a bike parking area. In the other direction, the splash hit the second floor of a classroom block 30 metre away and made it rain on the far side of the science block that was next to the pool.
We made silver azide at school, filled a drinking straw and set it off in the local park. I was deaf for several minutes - never heard such a loud bang. The other one was a paint tin full of a stoichiometric mix of Fe2O3 and Al powder. Because it was so fine there was lots of air in the mix so once it got going there was a beautiful silver fire fountain and molten iron flowing across the ground. These days we would be banged up in Paddington Green pronto!
"Hydrogen baloons with lit fuses floating at the ceiling - you name it."
Beginners! We had a means of inflating balloons with town gas (coal gas). Blotting paper impregnated with sodium chlorate as fuses and several match heads as dets. There were launched outdoors from the bottom of a deep, narrow valley after dark. The bang echoed nicely and the burning match heads arced across the sky.
One bonfire night ny dad got some huge plastic bags (maybe 10 times the size of bin liners) and filled one with coal gas and lit a long fuse to it. The bag peeled back releasing a burning ball of gas that floated up until it got to about two foot across when it exploded with a loud pop.
The next one contained coal gas and the exact right amount of O2 (from a dentist) to combust the coal gas (a uni prof for a dad comes in handy some times) and a long fuse of string and paraffin lit, The flame reach the plastic bag and there was a flash and a bang so loud that you could hear it echo off buildings 15 seconds later - which was impressive as most people were now deaf. It was about 10 minutes before the fireworks in the area recommenced. I still swear to this day that the explosion wrote 'bang' in cartoon letters.
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"thermite is also used for welding"
When BBC TV science programmes were about substance rather than style - there was one about using explosives to shape metal. IIRC in one example they had two steel sheets one above the other - with the top one angled to only be touching along one edge. Setting off an explosive charge between the plates caused the top one to fall flat. It ended up neatly welded to the bottom one over the whole touching surface.
@AC - This one?
https://youtu.be/2vqgKrJUA3w
If not it's a damn good little documentary on the subject anyway.
Oh an as for thermite and welding - it's how they fix railway track lengths together. Quite impressive to watch it in action.
Ah, the days of our yoof...made a hot air balloon out of a trash bag filled with hot air. Attached the better part of a roll of tin foil tailing behind it. I heard the radar personnel at Logan airport thought it was a DC3 that had somehow gotten misplaced.
"Those were the days... Me coat, the one draped over the zimmer frame."
Second year Physics at Secondary Technical School involved our ex-submariner teacher letting us play with a large beaker of mercury. Invariably we then chased beads of mercury across the bench.
A junior Chemistry teacher took us outside on to the lawn and created a pile of chemicals to demonstrate the Thermite action. At the tip of the pile was a magnesium strip as a fuse. It was a windy day - so the boys were formed into a shield round the pile.
Every time the teacher touched a match to the fuse the boys skittered away and the match went out. Eventually he managed to persuade the circle to stay intact until the firework spectacular started. The caretaker was not impressed by the bald patch on his lawn afterwards.
Several chemistry teachers had a brown streak up the back of their clothing from lecturing in front of their bench with the bunsen burner lit.
I do remember, as a Mastercare service engineer discovering that it was possible to get a 1.7 diesel Corsa to wheelspin in second gear in a PC world loading bay at the rear of the store....
I also managed to almost get all 4 wheels off the ground on a hump backed bridge with the same car..
AC for obvious reasons...
In a different existance many years ago, I used to work as a vehicle inspector on a company car scheme that had the mk1 1.2 corsa's ex british school of motoring on their books as a low budget sales option when we defleeted them at a year old, the question everyone always asked me was that would the little corsa's be enough to use occasionally in modern traffic, performance wise.
One day we were moving a corsa and a calibra between branches, down a particulary straight well known wide stretch of road, so it was decided this was "seeewhatit'll do" day.
For my sins, I got the speedo on that little 1,2 corsa up to a indicated 120mph and when I finally brought it into the compound, it stank, you know that ragged abused smell, the brakes smelt hot, the rest of the car etc. We put it in for service early and it got a out of sequence oil change because the boss smelt it coming into the yard and thought we might have baked the fluids.
Later it went on sale for a bit lower than the rest in case it got any extra bills for engine work, and I used to see the chap who had it for his daughters first car, and he always told me how happy with it he was, said it got better than expected mileage and seemed free'er. So, thereon customers asking "its for my daughter to learn in, will it do 70 on the motorway?" could be honestly answered yes.
Almost as much fun as the guy who had a 2l astra sport, and used it for a 1/4 mile journey every day and no further. He wanted out his lease because it kept having issues, so we had it rebuilt, and I got it for long term test for a month to treat as my own car. I was only 20. two sets of tyres later, it ran really really well. He had it back, 3 months later it started again, so he brings it back moaning and leaves it for a test weekend. My boss slides me the keys and says "fancy a weekend out, fuel paid"...
Things like a good using now and again. The pay was crap, and winter conditions terrible, but the perks were great fun.
Italian tuning
I thrashed the nuts of a Sunbeam hatch for years. Well maintained, regularly saw 7000rpm, kept it to around 140,000 miles, took it off the speedo.
Not bad for an old push rod lump.
Took off road due to spares taking too long, in end it was the long wait for a clutch cable. Time for a newer car.
Had a 1.2 Agila recently, swapped the airbox for a 'sports cone' filter and it was happier over 80 (AC for obvious reasons). Went really well and since it was really a Suzuki Wagon-R it was light and there was loads of room in it. Only problem with those engines was they were cam chain (not belt) that after 120,000 rattled something chronic. Said goodbye to mine (sold it before it went bang) at 130,000.
When I picked up my new golf GTi turbo ~2000 I asked the mechanics if there was anything special I needed to do in order to keep it running smooth. They said take it easy in the run in and ensure to keep the turbo clean often by giving it good amounts of right foot regularly. So I did, at least twice per day, sometimes more. 8mpg along the m20 was seen a few times.
"and he always told me how happy with it he was, said it got better than expected mileage and seemed free'er"
Decarbonising the head and valves a bit, burning crap out of the exhaust and flushing with thin and hot oil is generally good for engines.
People often don't realise that cars are designed to survive quite extreme conditions. What they dislike really intensely is being driven slowly around town with cool engines, which is exactly what learners do.
"I got the speedo on that little 1,2 corsa up to a indicated 120mph [...]"
In South Africa the motorways were often dead straight. A colleague had imported his BMW 2002. One day he decided to show me what it could do. At 130km a hour - very smooth I thought - then remembered it was a British car with the speedometer in mph.
Many years ago I had a job where the pool vehicle was a shitty Ford of some variety and the gear lever gate was lopsided.
.1.3.5
2.4
It used to keep going 1 to 4 and the clutch was an on off switch. Handled like a turd and the controls were terrible.
I destroyed either the clutch or gearbox. As the car I had at the time had a gear lever directly connected to the box, rather than connected by elastic, and a clutch which was progressive, I treated any inferior transmissions with the distain they deserved.
I managed to break a few Fords until they got an Astra van, so much better!
Last time I had to drive a bad car it was motorway in 4th because the gearlever stuck in my leg in 5th.
As a truck mechanic years ago a group of us had one of the artics up to 50MPH at a standstill wheel spinning on ice in the yard.
It would have been interesting if the tyres would have worn through the ice, Volvo F12's were not renowned for having the strongest half shafts in the business.
"I also managed to almost get all 4 wheels off the ground on a hump backed bridge with the same car.."
It was reported that someone did that with a Renault Dauphin(?). The suspension system meant that all four wheels naturally tilted with their bottom edges inward by a large amount. On touching the ground they were tilted too far to regain road holding. The car merely pancaked with its wheels folded under it.
Back in the days of yore - about 1967 - I was travelling at reasonably high speed on my Vespa though the dark deserted streets of somewhere near Bloxwich.
Ahead is a humpy-back bridge over a canal. Suddenly, the Vespa, My pillion passenger and me are airborn.
Engine revs go WEEEEEEEEE! and all the lights blew.
We still had about 30 miles to go and quite a lot of that was on unlit country roads. I had to drive with my foot resting lightly on the foot brake pedal.That way the stop-light would come on so I had at least one working light should we get stopped.
Thankfully we made it without hinderance or incident and I made sure I never jumped a humpy again. (Well not on two wheels.)
I used to work for a car dealership, twice a week I would be sent down to Kingsbridge from Exeter & I always used to come back from the top of the Haldon Hills via a country road into Shillingford rather than the main A38.
Halfway down the hill was a lovely hump that I merrily launched into space in a BL Ital van twice weekly, then one day I forgot about the unsecured lump of dead engine in the back, which smashed into the rear of the drivers seat.
No long lasting damage to me fortunately or the van.
A relative used to work in a steel fabrication plant, which was in turn located in an old victorian mill. Lots of old, unconnected pipes, which led to the occasional prank where they'd dump some oxyacetylene into a pipe and then set it off with a lighter.
Over time, the scale of the pranks progressed, especially when they got into competition with the company next door. It started with milk cartons, progressed to taped up cardboard boxes and they finally called it quits when someone started to drag in a wheelie bin...
... WAS a biker, and the owner of the company. He never got into brawls in biker bars, though. Would you want to destroy your local? Instead, quite sensibly, he always took it outside.
This was 40 years ago. The company is still in business. He still runs it. Still a biker, and still frequents biker bars. Doesn't get into brawls anymore, though. Says at his age pain really hurts.
I remember being a young impressionable student at an undergrad open day at I-Can't-Remember university.
And some post-grad bastard thought it would be funny to throw liquid N2 at my bollock region. No harm done but I wasn't amused.
I did do science at Uni which was probably a mistake because it's hard, jobs are crap, short term contracts and poorly paid.
When I got my BSc(Hons) you could get more working on tills at Tesco than in a lab. And at least the job at Tesco was permanent.
The fighting story reminds me of working for a leading organization in the information industry run by the BBC's favorite tech boss and namesake of every Nazi's favorite composer.
The aforementioned boss and his macho bully boy senior sales team would go our of their way to start punch ups in and around bars near the Leicester Square HQ of the company. The only thing I wished was that I was on the other side and could have punched Danny boy's lights out myself (a view held by almost everyone who has ever worked for him I think!)
Not really IT related, but in the days when I used to do theatre, I spent a couple of weeks teching a 3-week run for a touring company.
By the end of the second week the director (who was also playing the title role) and cast had had enough of each other and the director started fighting on-stage with the cast during the performance.
The show was supposed to be profit sharing among the company, except for me, as being called in from outside I was paid a fixed rate. Audience numbers were so low that I was the only person who made any money on the show!
Needless to say, the show didn't make it into the third week, and I ended up getting hammered with the cast.
I remember one day during a quiet moment in a chemistry lesson, when one of the kids in my class observed that the gas tap and the water tap had the same size fitting. They proceeded to connect a bunsen burner to the tap, and turned on the water. A rather spectacular fountain effect was followed by a fairly harsh bollocking.
Did you know...
I imagine you do, much as I know that a "cherry bomb" does not float, but sinks to the bottom of the bowl, where its explosive energy is tamped by the weight of the water above and quite effectively splits the bowl in half.
This results in an interesting Polaroid photo (sadly, now lost), a mother who is laughing so hard she can't yell at you, and a frantic lesson in toilet replacement before Dad comes home from a business trip.
// not me, my next door neighbor
// partners in mayhem
"[...] where its explosive energy is tamped by the weight of the water above and quite effectively splits the bowl in half."
Newly qualified junior chemistry teacher demonstrating how sodium reacts with water to leave it alkaline. First attempt - litmus strip dipped in the water stays neutral. Bigger lump of sodium put into the special mesh container on a handle. Lifts it out of water - shows it fizzing - indeed sparking. Loud bang and the pneumatic trough splits neatly into two halves and a bottom. Loud cheers from the class.
A few years later the VIth Form doing work in the chemistry prep room. Sudden sound of a bang followed by a cheers. A new junior chemistry teacher had repeated the experiment.
This post has been deleted by its author
At a previous place of employment, one of the maintenance staff tried disposing of a load of sodium lamps by throwing them in a skip. Unfortunately the lamps all broke on impact, and there was quite a bit of water on the bottom of the skip. Fortunately the skip was fairly sturdy, so nobody got badly hurt.
At university, sometime during the 1970s....
The feed into a water tank at the roof of one of the buildings developed a fault and the tank began to overflow. The overflow came out in a small pond at the front of the building
For some reason the incoming water supply couldn't be easily isolated, and the overflow pond started look like it was in danger of overflowing itself, thus flooding part of the campus.
A pumping unit was scavenged and used to drain water from the overflow pond, and eventually somebody managed to turn off the mains water feed into the tank.
Heads were being scratched though, as after an hour or so water was still flowing into the overflow pond. Only then did someone question where the pond was being pumped out to....yes, into the water tank on top of the building.
So I am not supposed to confess that my first week at a mid range public school on the edge of Salisbury Plain included how to vary petrol bombs between incendiary and blast devices.
Less than a decade later I discussed the matter with my Royal Engineer demolitions instructor. I had graduated to better things and PE4 is such fun!
I had a phone job in a call center separated by a 6-foot wall from another department. They had lots of rubber bands, and eventually they were sailing back and forth over the wall as we playfully "shelled" each other. Well, rubber bands lack range and accuracy, hardly the weapon of an American rifleman.
So I invented coffee darts. Cut two slits in one end of a plastic coffee stirring straw, slightly offset. Punch a staple longways near the other end and bend up the outer "arm" a wee bit. Slip small pieces of index card in the slits for fins. String a rubber band between two fingers, hook the staple on for a launching hook and let fly. They're accurate to quite long range, and simply lack the mass to hurt when they get there. Your target often doesn't notice being shot if they didn't see it. Of course, never aim for the head or face, but they're a blast. Also good for startling cats, lol.
On a 2nd generation mainframe the 3/4 inch magnetic tape cases had a very thick band of rubber as part of the locking mechanism. While long batch jobs were running on the night shift the operators would stretch and fire these bands at each other. Inevitably one night one hit the "reset" button on the console.
Fortunately it was not unusual in those days for machines to abort themselves for no obvious reason - so the lost time could be logged as such an "unknown".
The tape decks were very large and on the evening/night shift the room lights were switched off as the console was a large array of lit buttons. It was a lay person's idea then of what a computer should look like. One programmer would often go to supervise her overnight jobs - and catch up on some amorous activities behind the tape decks with the handsome shift leader.
There was a computer room on the top floor of a building - which also had access to a flat roof area that overlooked the adjacent road's numerous multi-storey apartments. The operators kept a pair of binoculars on the console for one particular nightly show.
As they say "The past is another country".
Minor league confession here, I worked with a Mr Bean lookalike, soundalike & presumably smell-alike as he had little sense in regards to personal hygiene (Proudly mumbling that he was staying in a B&B as his car was off road (A rusted out Ford Escort with a mound of seagull shit on the roof so high, that it looked like a flock of Albatrosses had crapped on it),
I used to set up rubber bands on my equipment test jig, so placed to fly across his fingers as a series of adjustments were needed from the board under test he was working on & then remove myself from the equation by getting a component swapped out, leaving him to work out (unsuccessfully) who was flicking rubber bands at him.
"And probably also because the people involved knew that high concentration acids are mildly dangerous and were exceedingly careful when brewing their little conconctions."
When picking up the jar of instant coffee I always hold it by the body - not the lid. When replacing the lid it is always screwed down - never just lightly engaged. The result of secondary school chemistry safety practices. Always cover the label with your palm when pouring liquid chemicals. Always add acid to water - never add water to concentrated acid.
A neighbour's son cut his finger when sawing a piece of wood. It seemed that the modern IDT(?) workshop classes had never taught him our woodwork teacher's safety list.
Never put any part of the body in front of a sharp edge.
Keep tools sharp.
Always use controlled hand power when executing a cut.
Always place tools in the bench well when not being used - planes on their side.
When carrying a chisel - keep you arm by your side. Hold the chisel sharp edge down - and place two fingers against the flat of the edge.
When sawing put a finger alongside the handle for stability.
Saw with long slow strokes to avoid it jumping or wearing the teeth unevenly.
I did work somewhere where reputedly the police were called to the company Christmas 'do' 3 years running (never went, we had our own departmental one instead).
Another company I worked at, two guys from the US office had a brawl outside a pub when over in the UK. Maybe it was the stronger beer. The next day one refused to be driven back to Heathrow by the other one in their hire car, saying 'I'm not going in a car with him, he said he was going to fucking kill me'.
Later apparently they had a punch up at a sales conference or somesuch in the US, someone tried to intervene and they both turned on him. This third guy then complained to H.R. This resulted in a company wide ban on alcohol on expenses at any time for any purpose.
Went to one of those public/schools/fun lectures when I was at school, at what ended up being my Uni. The whole theme was "things wot go bang and make bright flashes" and didn't disappoint. The part that stands out in my mind though even after 25 years is the lecturer messing around with liqud oxygen (dipping digestive biscuts in it and setting them on fire was a good start) and saying thusly:
"Now this is pretty dangerous stuff, and the British Oxygen Company, who make it, won't give it to pyromaniacs like me. Here at the university, however, we make our own. and they WILL give it to pyromaniacs like me."
He then proceded to demonstrate oxyacetylene bubbles, fun things to dip in liquid oxygen and set on fire, and many more loud explosive things.
It was a fine time to be an impressionable youth.
That sounds like Dr John Salthouse, saw his talk on several occasions and even had the honour of standing by with a fire extinguisher to chase the biscuits around the stage, watched him blow his eyebrows off once with home made gun cotton, the man did a great show
https://www.youtube.com/watch?v=fVDnbUj7qzw
very shaky camera but gives you an idea of what he got up to
At Grammar we had a Chem teacher who quite often would light up his pipe at the end of class if there was a break before the next group of reprobates turned up for education (our English teacher would often smoke in class).
Was fine (well, aside from what we now all know) until one lesson where we'd all finished and poured the excess ether into the sinks. We discovered the connected drains when he tapped a still smoldering dottle out into the sink at one end of the room and columns of flame erupted the length of the room. The tiles along the ceiling were discoloured until the 'incident' in the workshop on the ground floor (science block has a wood/metalwork shop and domestic science on the ground floor, then bio, chem, and physics on the floors above) which resulted in an oxy-acetylene explosion which required the entire science block to be rebuilt...
The teacher used to stand a glass beaker of ether on a large watch glass of water. He then pumped air into the ether - which evaporated. The latent heat of vaporisation then caused the water to freeze. He didn't seem concerned about the amount of ether now in the air.
Doing organic chemistry in the VIth Form we saw what happens when ether vapour escapes over the side of a beaker. It rolled invisibly across the shared bench top - until it met a bunsen flame. Wooof! all the way back to its source.
One day someone overheated a beaker of either benzene or toluene. It caught fire and the air in the lab was filled with little black particles gradually dropping down.
A similar effect was caused on a sunny day when a pipe-smoking colleague discarded a partially unextinguished match into his waste bin - which was full of plastic coffee cups. As we had had a fire training session the previous week I knew what to do.
Grabbed the CO2 (not powder) extinguisher from the corridor. Remembered to remove the safety pin - pushed the nozzle close to the contents of the blazing bin - and pulled the trigger. Oops! the bin's contents were blasted into the air - fortunately the force also stopped the flames. The air was then filled with black oily smuts slowly falling onto every flat surface.
These are not really funny...
There was a certain council in the UK that used to keep its backup tapes in a derelict building with no security.
the site used to house a council dept but had been stripped apart for the massive fire safe.(bout the size of a bank vault)
The council could not afford to move the safe so they kept using it
.... I was recently shown the new fire-proof room that had been built to house the antique paper records that were still being used daily (I'm omitting the company name)...... very solid construction, looked really good.... except one problem. They ran out of budget. So there was no roof. A nice clear view up to the wooden rafters.
After I graduated, with no idea what to do next, I took a job in a mail order company as a filing clerk. We had piles of coupons clipped from magazines and had to fit these into plastic wallets in the cabinets. It was a horrible job, painful because the wallets had to be packed stupidly tightly with the plastic cutting into our fingers. Tedious in the extreme, too. And it was instantly obvious that there had been multiple successions of clerks. The files started in perfect order, then as you looked back became more and more random. Then became ordered again. And so on.
The papers came in bundles, tightly held in rubber bands. Bored to death and knowing we'd get fired soon I set up various entertainments, some rubber band focused. Flicking rubber bands over the partition into the manager's office when he was out ( extra points if they landed on his chair) and making the biggest rubber band ball are the two I can remember.
Only 'explosive' event I can remember from school (public, expensive), involved a certain teacher and his revenge on the class prankster.
One morning we all trooped in for a lesson about something unrelated, and there was a trolley at the side setup with a box, wires, and a switch. Normally we'd all ignore it, but said prankster couldn't resist sitting next to said trolley, and at an idle moment, flipping the switch.
Nothing happened for about 5 minutes, and he forgot about it, then the entire class was elevated 2 foot into the air when the rather large electrolytic capacitor hidden in the box exploded. Right next to the prankster. :D
Teach just chuckled and got on with the lesson, prankster had to sit in his wet trousers for the rest of the lesson. :)
Incidentally I ended up doing a project on exploding electrolytic caps and measuring their electrical signatures as they went - you can tell when they're just about to go if you're monitoring the right signals.
"- you can tell when they're just about to go if you're monitoring the right signals."
As a teenager I built a new high voltage power supply for my amateur HF transmitter. Switched it on and tried to measure the DC output. It was higher than expected - but then started steadily falling. While puzzling over the situation there was a loud bang and the electrolytic capacitor discharged a mixture of paper and aluminium foil up the wall of my bedroom. Luckily I wasn't directly over the capacitor - which was probably getting on for a 2 inch (50mm) bore mortar. I had forgotten the 1.4 x RMS multiplier when selecting the components.
Recently I bought one of the small Chinese modules that do voltage up conversion. Up to 32 volts in - up to 35 volts out. I only needed 12 in to 15 out. Unfortunately the voltage adjustment used a small multi-turn pot. Trying to apply the meter probes to measure the no load voltage was awkward - when simultaneously trying to turn the pot. BANG as the module's output capacitor's case launched itself into the air - with a ricochet off my finger. Luckily it was small and only stung - but it could have been aimed at my face.
The output capacitor was marked as 35 volt - and presumably my twiddling the pot had taken it beyond that limit. The supplier gave a full refund after I pointed out that pictures of apparently the same module from other suppliers showed a 50 volt capacitor.
About 30 years ago we were brought in to update the operating system and to update the companies telecommunication system. The third day I was there I got a call about something that wasn't quite right going on the operating system, I asked the operator to step aside while I issued some operator commands to try and determine what was going on. After I looked at the output of the operator commands. I stood up and gave the operator in charge of the console. I was trying to think what would cause the situation and I was slowly moving back inches at a time because I wanted to stay out of the way of the operators. I was thinking and not paying attention to anything other than the operator's movement. The operator got up from his console and I stepped back. Suddenly I heard a crack and I went flying down and backward. The raised flooring in the computer room had started to fall apart (nobody told me until afterward). I was wearing a suit and my pants leg was split open and a little blood was coming out. I got up to see if there was any other damage and there wasn't but the blood turned into a trickle. The company was thankfully located downtown and there were 1 or 2 hospitals nearby, so I chose the one I had been there before and took a taxi there to the emergency room. Luckily there were only 1 or 2 people in the emergency room, so I was seen as soon as the registration was done. To make the story a little short, they cut off one leg of my pants and put a bandage on my leg, They discharged me, but I could go back to work with only one pant leg covered, so I decided to go home and change. AÏter changing I went back to work. I brought with me the receipt for my suit (I had just purchased it 5 days before). After I got settled into my desk, I filled out an expense report for the suit and the taxi cabs I took. I took the paperwork to my bosses boss and handed it to him and he said what is this for and I explained to him what had happened in the computer room and how I fell through the floor. All was in order as far as I was concerned but then he started in why didn't I look where I was going and I explained again I was moving backward to keep out of the way from an operator. He said "no it's your fault", I said you have got to be kidding, he said no go away I have work to do. I was mad by that time, so I took the elevator up 5 floors to the executive floor and looked to see if VP of IT was there and luckily he was. I walked up to his secretary and asked if I could see him for 3-4 minutes. She looked at his calendar and said let me see. I sat down (now I was starting to get sore from the leg). She said he will see me now. I limped into his office and explained the incident and how the boss would not authorize payment for the suit and the taxi cab rides. He asked me if I was alright and I said yes except for a stiff leg. He got on the phone to the legal department and after explaining to a lawyer what had happened, he got off the phone and signed the expense report and asked me to stop by the lawyer's office and sign some paperwork, which I did. Next day my bosses boss was no longer employed and the operators were told to be careful around the raised flooring and that new tiles have been ordered.
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