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rachthepirate
82006.  Wed Jul 26, 2006 6:40 pm Reply with quote

Tas wrote:
When I used to practise Archery, we used to have exploding flour casks set behind the targets when we were doing our shows. Hit the bullseye an BOOOOOM! Little explosion and a fair bit of flame! Brainiacs exploded a pallet of the stuff, and if brought back some fond memories.

(Incidentally, flour and flour-dust are thought to have been a major contributory factor in the initial fire that started the Great Fire Of London in 1666).

:-)

Tas


That is a great idea! I shall have to propose it to the company of archers I shot with. How awesome!!

 
dr.bob
82044.  Thu Jul 27, 2006 4:18 am Reply with quote

Celebaelin wrote:
Quote:
so when the lamp is turned on it emits a dim red/pink light to warm the sodium metal and within a few minutes it turns into the common bright orange/yellow color as the sodium metal vaporizes.


orange/yellow? Talk about sitting on the fence :)

Interesting to know why they start off with a pinkish light, though. I'd always wondered about that.

Celebaelin wrote:
If you look at the picture would you say that was yellow or orange?


I would say it was orange.

I would also say that it doesn't look the same colour as most sodium lights that I've seen. Mind you, given all the possible effects on colour in the process to taking a picture, developing a picture, and displaying it on the web, that might not be too surprising.

Must make a note to go and look at some sodium streetlights and double check what colour they are. At least, I will do later in the year when it actually starts getting dark again :)

 
samivel
82055.  Thu Jul 27, 2006 4:58 am Reply with quote

Isn't it possible that some are yellow and some are orange?

 
Tas
82069.  Thu Jul 27, 2006 6:10 am Reply with quote

Quote:
That is a great idea! I shall have to propose it to the company of archers I shot with. How awesome!!


You have to be VERY careful in ultra-dry conditions such as are prevailent these days.

:-)

Tas


Last edited by Tas on Thu Jul 27, 2006 7:26 am; edited 1 time in total

 
Celebaelin
82077.  Thu Jul 27, 2006 6:50 am Reply with quote

samivel wrote:
Isn't it possible that some are yellow and some are orange?

Well, yes but only in that there are two sorts of sodium lamps.

LPS Lamps (Low Pressure Sodium), also known as SOX Lamps (Sodium OXide), which

Quote:
...produce a virtually monochromatic light in the 589 nm wavelength. As a result, objects have no color rendition under a LPS light and are seen only by their reflection of the 589 nm light.


This (589nm) is the Sodium D-line which this site describes as yellow

http://cc.oulu.fi/~kempmp/colours.html

This image shows the Na-D 589nm colour and I'd be happier to call that orange



but whether you think it's yellow or orange it is definitely only one colour.

Calling it yellow/orange puts me in mind of Lloyd George

Quote:
'He has sat on the fence so long, the iron has entered his soul' -- Lloyd George on Sir John Simon


but there are also High pressure sodium (HPS) which

Quote:
...are smaller and contain some other elements (for example, mercury), produce a dark pink glow when first struck, and produce a pinkish orange light when warmed up. These lamps produce continuous spectrum light (not monochromatic)

http://en.wikipedia.org/wiki/Sodium_vapor_lamp

Under HPS lamps you can distinguish the colours of objects (with some difficulty I suspect), under LPS lamps you can't.

 
Ian Dunn
152448.  Thu Mar 01, 2007 3:22 am Reply with quote

Can I ask a question?

We had a bottle of ginger beer in our fridge, and the fridge was so cold that the ginger beer began to freeze. Then yesterday, the ginger beer exploded. The explosion was so powerful, it broke the specially strengthed glass it was lying on. Luckily, no-one was around when the bottle exploded.

I'd like to know why the ginger beer blew up, and if any other fizzy drinks can explode when chilled.

 
strukkanurv
152452.  Thu Mar 01, 2007 3:47 am Reply with quote

I remember many years ago when I was a kid....okay, okay, I know I'm still a kid...anyway, my mother had some ginger beer given to her by a friend - it wasn't quite ready & needed to ferment or whatever it does. One night we kept hearing these funny dull popping & banging noises. The next morning, we discovered a huge puddle over the kitchen floor & discovered the beer had forced the tops off all the bottles in the cupboard.
I recall it was classed as some sort of plant, but just looked like sandy sediment in the bottom of a bottle.

 
smiley_face
152463.  Thu Mar 01, 2007 4:47 am Reply with quote

Ian Dunn wrote:
Can I ask a question?

We had a bottle of ginger beer in our fridge, and the fridge was so cold that the ginger beer began to freeze. Then yesterday, the ginger beer exploded. The explosion was so powerful, it broke the specially strengthed glass it was lying on. Luckily, no-one was around when the bottle exploded.

I'd like to know why the ginger beer blew up, and if any other fizzy drinks can explode when chilled.

The solubility of gases in water (which is what ginger is primarily made of) varies with temperature. At higher temperatures, the solubility is higher, thus when you chill the ginger beer, the solubility falls, the gases can no longer be dissolved in the ginger beer and so they "outgas" into the bottle. This means that there is more gas in the bottle than there was before, so the pressure builds up, and *bam!* you get an explosion.

 
dr.bob
152465.  Thu Mar 01, 2007 4:48 am Reply with quote

Not to mention the fact that water expands when it freezes.

 
smiley_face
152467.  Thu Mar 01, 2007 4:50 am Reply with quote

dr.bob wrote:
Not to mention the fact that water expands when it freezes.

And, rather confusingly, when it heats up. Bloody hydrogen bonding over-complicating matters!

 
Archie
152473.  Thu Mar 01, 2007 5:11 am Reply with quote

Ian Dunn wrote:
Can I ask a question?


Yes you can. In fact, it's positively encouraged.

 
grizzly
152557.  Thu Mar 01, 2007 8:09 am Reply with quote

Quote:
I recall it was classed as some sort of plant, but just looked like sandy sediment in the bottom of a bottle.


Would you be referring to the yeast (a type of single-celled fungus)?

 
Lucifers_Lady
228965.  Thu Nov 08, 2007 5:41 pm Reply with quote

.


Last edited by Lucifers_Lady on Fri Apr 04, 2008 1:53 pm; edited 1 time in total

 
Jenny
229306.  Fri Nov 09, 2007 2:05 pm Reply with quote

Ah yes the bombardier beetle - the creationists used to think of this one as their best friend in a defence against the wicked evilutionists. Some of them still do, I believe.

 
Jerrythesheep
951285.  Thu Nov 15, 2012 9:30 pm Reply with quote

@ smley_face

Sorry but the solubility of most gases in water decreases with rising temperature. Warm soda will fizz and bubble much more than cold soda. Henry's Law states that the solubility of a gas in a liquid is dependent on the partial pressure of the gas above the liquid. The warmer the liquid, the higher the kinetic energy of the molecules, the more likely bonds between solvent and gas molecules will be broken. Alternatively, the formation of bonds between gas molecules and solvent molecules will be exothermic. Heat can be thought of as a product of the reaction and Le Chatalier would predict that the solubility reaction would move to the left (free gas and solvent), releasing gas as the temperature rises. That is why when you draw a glass of cold water for your bedside table at night, in the morning it usually has bubbles in it as the water temperature has risen to the room's temperature.

 

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