Reply With QuoteMore than what? Where would you like us to begin?Originally Posted by seren
Yup. Gold star for Matt.
Ever seen a pic of it? It's fascinating!
More than what? Where would you like us to begin?
Be skeptical of the things you believe are false, but be very skeptical of the things you believe are true.
Yeah did a bit of Space Science as part of my Degree. Comes in handy for witty retorts when someone say "It's not rocket science"
Start at the very beginning (it's a very good place to start).
Explain, in more than one sentence, what is fire and why does it behave the way it does. Please.
And also -jet lag. It's supposed to be worse going one particular way- firstly, is that true, and if so, which way's bad and which way's good- going with the earth's rotation or against it? I find coming back from Asia a lot easier than going.
Snaffling sheep from the flock of woo
-bobdezon
Fire is hot partially ionised gasses undergoing a self perpetuating rapid oxidation reaction.
When you burn wood it isn't actually the solid wood that burns. The heat from the flame causes outgassing from the wood - it is those flammable gasses that burn. That is to say they undergo an exothermic oxidation reaction (exothermic = it releases heat energy) Typically the products of these reactions are carbon dioxide and water. These will tend to smother the reaction unless they are removed and replaced with fresh oxygen. This will tend to happen by convection. Turbulent convection current result in flickering flames. In a yellow flame not all the available carbon is oxidised. The yellow that you see is hot soot. If more oxygen is added to the mix then all the carbon is oxidised releasing more energy. As such you get a hotter blue flame.
For what it's worth, in my limited experience of transatlantic flights travelling west (with the sun) is much easier than back home (against the sun)
I have heard that our circadian rhythms if left to their own devices wihtout external cues will average out to 25 hours a day. This might partially explain why it is easier to extend our day (as we do when travelling west) than compress our day. Certainly I heard of some productivity benefit to roating shift work where shift workers are asked to advance their shift by 8 hours every week rather than other schedules tested.
I watched those BBC progs analysing the credit crunch. They said some of the people who 'securitised mortgages' came from NASA! Now we can all see what rocket scientists can really do ...
OK. You have something that can be oxidised (fuel) in the presence of oxygen. In most cases nothing happens at room temperature because there is a potential barrier to get over before the fuel and oxygen molecules can start to dissociate and so recombine as something like water and carbon dioxide. Heating gets over this barrier and the oxidation starts. If the oxidation releases enough energy to keep the temperature up above this ignition point, the fire continues without any further heat input, and generally results in a net heat output.
Flames happen because the heating makes the air in the burning area less dense, so it rises and is replaced with cooler air from outside at the bottom. This keeps the fire supplied with fresh oxygen. This rising air carries some of the burning material with it. If it is something that gives out visible light when burning, the flames are visible, e.g. yellow flames from burning soot from wood, coal or hydrocarbons - unless there is so much oxygen that the carbon burns completely at the start and there is no soot to see.
As far as I know, the human daily cycle is a lot better at adapting to a longer gap between days than a shorter one - though I suppose you could try skipping a whole day when going the other way. I think people deprived of day/night cues typically free-run on a cycle of about 25 hours.And also -jet lag. It's supposed to be worse going one particular way- firstly, is that true, and if so, which way's bad and which way's good- going with the earth's rotation or against it? I find coming back from Asia a lot easier than going.
Be skeptical of the things you believe are false, but be very skeptical of the things you believe are true.
On a point derived from jet lag.
If we went into space like Star Trek how could/would this effect our systems, sleeping patterns, menstral cycles etc.
Would the problems be different moving instantaneously from one system to another (SG1).
PS
I personally have a stargate, it doesn't work, maybe no-one else has built theirn yet.
Last edited by polomint38; 22nd January 2009 at 04:38 PM. Reason: spelling - sorry
______________________________
You need an excuse? Just drink
skbuncks
her cheese slid off her cracker many moons ago
floppit
I had a stargate once...green it was.
I think fire is plasma, but then the descriptions given don't sound very plasma-y, so what is plasma and is fire plasma?
Plasma is a bunch of separate nuclei and electrons, where the temperature is too high for them to join together as atoms. Since fire is a chemical reaction, and chemical reactions require atoms or molecules, a plasma can't be a fire in the usual sense.
You can have something called a "plasma flame" or "plasma torch" but these are not flames in the chemical sense, just streams of ionised gas which have been heated with something like an electric arc.
Be skeptical of the things you believe are false, but be very skeptical of the things you believe are true.
I have a friend who's PhD was on infinity - he tried to explain it to me once (something to do with snooker balls IIRC) but either beer or my small brain -perhaps both prevented any real grasp of what he was talking about. He went on to work in the insurance business which should worry us all!
"No statement should be believed because it is made by an authority." Robert Heinlein
And I thought it was David Bowie's fault!!
"No statement should be believed because it is made by an authority." Robert Heinlein
That was about the sum of my knowledge and the hotel analogy is about as far as I can get my head around. You should try the "Science of the Discworld" books, well written and a Pratchett story woven throughout. Infinity was covered in the third one IIRC
Defendants might as well have said: Beneficent creatures from the 17th dimension use this bracelet as a beacon to locate people who need pain relief and whisk them off to their home world every night to provide help in ways unknown to our science.
Judge Frank Easterbrook commenting on the Q-Ray bracelet
"For Gods sake you're an American! Stop thinking of the consequences and blow something up" - Stan Smith, American Dad!
That's an interesting question. I suppose we'd have to fake "days" and "nights" or something.If we went into space like Star Trek how could/would this effect our systems, sleeping patterns, menstral cycles etc.
What is the ingredient in bubblegum that makes it different (ie makes it make bubbles) to chewing gum?
Snaffling sheep from the flock of woo
-bobdezon
As far as I'm aware it's not so much a different ingredient as a different variety of the same ingedient - originally a type of latex rubber called chicle but now a synthetic rubber with similar properties. (I had to look that up)
Latex comes in many varieties with different physical properties.
Physical properties like stiffness, hardness, brittleness, elasticity and plasticity can be determined by how the long hyrdocarbon chains loosely bond with one another.
Brittleness is how much strain (deformation) a material can take before it fractures. Both chewing gun and bubble gum will engage in plastic flow. When subjected to a certain stress (force/cross section) they will deform by a huge amount and not snap back to their origninal shape. After a certain amount of plastic flow both will fracture but that amount is much greater in bubble gum than chewing gum.
If I had to guess I'd say that the reason for this on a molecular level would be that bubble gum had longer hydorcarbon chains than chewing gum but that would just be a guess.
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