NickLee Posted June 27, 2003 Share Posted June 27, 2003 Are you thinking of liquid nitrogen or liquid oxygen? --N Link to comment Share on other sites More sharing options...
mark b Posted June 27, 2003 Share Posted June 27, 2003 liquid oxygen. cant remember what one is colder but the colder of the two. I could look it up but if is half five on a poets day! Link to comment Share on other sites More sharing options...
Ben Posted June 27, 2003 Share Posted June 27, 2003 liquid nitrogen or liquid oxygen? it works with both (I think that was the experiment dose anybody else remember it. Not sure about the hammer bit. If any body can fill this gap in my childhood it would be appreciated.) well I know the experement well and have tired it myself a few times but I have nopt known of the hammer bit, and it doesnt sound like it would work, adn the most it would snap not shatter Link to comment Share on other sites More sharing options...
PeterT Posted June 27, 2003 Share Posted June 27, 2003 I remember a programme we saw at junior school years ago and it showed what effect liquid oxygen had when certain objects were dipped in it and then ignited... It was all quite impressive until they got to cotton wool.In air it burned quite subtly but having been dipped in liquid oxygen we knew something was up when the guy igniting it moved about 10 feet away with a bloody big face shield on.It exploded so completely there was nothing left! Well impressive especially to 9 year old pyromaniacs B) Link to comment Share on other sites More sharing options...
peter Posted June 27, 2003 Share Posted June 27, 2003 It was all quite impressive until they got to cotton wool.In air it burned quite subtly but having been dipped in liquid oxygen we knew something was up when the guy igniting it moved about 10 feet away with a bloody big face shield on.It exploded so completely there was nothing left! Well impressive especially to 9 year old pyromaniacs B)Perhaps a word of caution to anyone using pyrotechnics and dry ice effects? Link to comment Share on other sites More sharing options...
themadhippy Posted June 27, 2003 Share Posted June 27, 2003 Perhaps a word of caution to anyone using pyrotechnics and dry ice effectshttp://www.click-smilies.de/sammlung/fragend/confused-smiley-008.gifsurley dry ice is co2 and it sort of removes any oxygen, no oxygen no fire,then again im not very good at chemistry so could be wrong Link to comment Share on other sites More sharing options...
Ben Posted June 28, 2003 Share Posted June 28, 2003 well you are right that its CO2 but CO2 is C +2O I.e I carbon atom and 2 oxygen atoms, it does not however burn. it is also not always true to say no oxygen no fire as nitrogen burns nicely as do some other gases and so this is not the case, also the only way to get no oxygen would be to suspend the effect in a perfect vacume (no not a dyson) asotherwise the oxygen in the air would react with it. Link to comment Share on other sites More sharing options...
robloxley Posted June 28, 2003 Share Posted June 28, 2003 Generally the banana trick is done with liquid nitrogen, as it's generally more available and somewhat safer... Another fun game is to make instant ice cream by mixing liquid nitrogen and double cream - and flavouring of your choice - but beware it's quite cold! Link to comment Share on other sites More sharing options...
Ketil B Posted June 28, 2003 Share Posted June 28, 2003 well you are right that its CO2 but CO2 is C +2O I.e I carbon atom and 2 oxygen atoms, it does not however burn.It will if you give it allot of energy and the carbon will split from the oxygen B) the same thing has happened in sum industrial fires when the H2O from the fire trucks adds to the blase :P Link to comment Share on other sites More sharing options...
steven Posted June 29, 2003 Share Posted June 29, 2003 Actually it's degrees Celsius, but just plain "Kelvin" if it's Kelvin. As in 25 Degrees Celsius = 298 Kelvin That's if you're a "real" scientist.... or being really pedantic 25 degrees celcius =298.15 kelvin Another fun game is to make instant ice cream by mixing liquid nitrogen and double cream - and flavouring of your choice - but beware it's quite cold! Amazing fun, and a good way to spend a physics lesson only weeks before you final A-level exams Link to comment Share on other sites More sharing options...
robloxley Posted June 30, 2003 Share Posted June 30, 2003 Back to the original question, it's somewhat scary how many people interviewed for technical theatre jobs fail at:- being able to wire a plug- knowing what UK mains voltage is- having a decent appreciation of the relationship between power, voltage and current- knowing what the earth wire does- having any concept of what a three phase supply is For some more teasing questions (though their relevance may vary according to the job) try asking:- how an analogue dimmer works- how a 12V DC PSU works- how a balanced line works- to explain the concept of a loudspeaker's impedence- to talk through programming a lighting desk - without it being in front of them- the difference between an RCD/RCCB, an MCB/MCCB and an RCBO; and the difference between type B, C and D MCBs and therefore discuss what circuit protection you might want on a theatre lighting system Link to comment Share on other sites More sharing options...
smeggie Posted June 30, 2003 Share Posted June 30, 2003 too right - when I did a show at a fairly local venue, the resident tech was unable to diagnose that the fuse had blown on one channel of the betapacks that were used - this is fairly suss as there indicators on the front panel. the reason it had blown was there was about 3K of load on the channel and one 650w lamp blew, taking out the fuse. [not my design though - so don't scream at me] not least of which, he was unable to program the board with a few simple scenes that then needed to be transferred onto submasters. this is worrying as he was the venues (only) assistant tech and the board was a sirius 48. oh dear! :( on another idea, its a shame that we tried the LN2 fog curtain trick and then didnt have enough double cream to try the other one ach, reality! andrew [ :P for ever] Link to comment Share on other sites More sharing options...
Angelic Posted June 30, 2003 Share Posted June 30, 2003 :P I have to say I've never tried the liquid nitrogen trick before, but I'm fat - and hungry, now where can I get some liquid nitrogen from for my lunch...... being able to wire a plug- knowing what UK mains voltage is- having a decent appreciation of the relationship between power, voltage and current- knowing what the earth wire does- having any concept of what a three phase supply is On a serious note, I really do believe that people that can't do the above shouldn't be allowed within 100 feet of any theatre - spectating or working! Link to comment Share on other sites More sharing options...
Jemma Posted July 1, 2003 Share Posted July 1, 2003 - how an analogue dimmer works- how a 12V DC PSU works- how a balanced line works- to explain the concept of a loudspeaker's impedence- to talk through programming a lighting desk - without it being in front of them- the difference between an RCD/RCCB, an MCB/MCCB and an RCBO; and the difference between type B, C and D MCBs and therefore discuss what circuit protection you might want on a theatre lighting systemFirst five questions, no problem at all. Good training means I can turn my hand to most things. However, the following five - who cares?!? (Not me, even though I enjoyed 'A' level Physics) Grateful to those of you who do, though, to stop things from blowing up! Guess asking these an easy way to sort out those of us who will go down the Stage Management route and those who prefer their LX & Sound toys. . . Link to comment Share on other sites More sharing options...
NickLee Posted July 1, 2003 Share Posted July 1, 2003 not least of which, he was unable to program the board with a few simple scenes that then needed to be transferred onto submasters. this is worrying as he was the venues (only) assistant tech and the board was a sirius 48. oh dear! :PProgramming a Sirius (especially the effects) makes you GLAD - so glad - that most desks nowadays have monitors +keyboards attached... N. Link to comment Share on other sites More sharing options...
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