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Lurid Archive
14:32 / 11.06.03
NOT because the light bounces off them and affects them but because our consciousness affects the outcome directly - Quantum

Given the nature of the thread, it should be pointed out that this is but one interpretation of QM. I don't *think* it is standard amongst physicists.

It also proved the existence of sixteen dimensions (at least) that Einstein theorised

Are you sure you mean "proved" here? I'm not sure that that statement would be uncontroversial in physics circles.
 
 
.
15:12 / 11.06.03
I thought there were 11 dimensions nowadays? Speaking of which, here's a question- if there are 11 dimensions, "where" are the others aside from the four we understand? Is "where" even the correct term?
 
 
tom-karika nukes it from orbit
17:39 / 11.06.03
grant- Five fundamental forces or fields in physics (Note I have lumped togther the force and it's associated field, so Electricity includes Electric Fields):

1. Gravity (The effects of mass on other mass)

2. Electricity (The effects of positive and negative charge)

3. Magnetism (These last two are linked together somethimes, as electromagnetism)

4. The Weak Force (This force turns an 'Up' Quark to a 'Down' Quark or vice-versa, and so is responsible for Beta nuclear decay. Pretty badly understood and very hard to measure)

5. The Strong force (This can't be observed outside the nucleus of an atom, but must be there or the thing would fly to bits. As we can't be in the nucleus of an atom, it is unobserved. It's really strong, as it overcomes the electromagnetic force between the protons in the nucleus. At the miniscule distances between the charges in the nucleus, the repulsive force is very strong)

The 'Holy Grail' of modern physics is often said to be a theory to explain how these five interact. The interaction of electricity and magnetism is quite well understood. But the way gravity interacts with certain aspects of them according to special relativity is pretty well in conflict with what happens on the sub-atomic level, where the Weak Force and Strong Force come in to play. Quantum Mechanics and Relativity cannot both be right.
 
 
tom-karika nukes it from orbit
17:55 / 11.06.03
Actually, having another look around text books, the fundamental forces are more usually grouped as four, electricity and magnetism together. I also realise the Quantum added a list of the fundamental forces on the end of one of his posts, and I've sort of repeated the same point. Sorry.

Now, can I ask a stupid question which I can't find the answer to anywhere?

What is the 'Agent' of a magnetic field? Like the good old photon is the 'agent' of an electric field, and the hypothetical Graviton is the agent of a gravitational field, what is the agent of the force that exists between two magnetised lumps of iron?

Or am I being incredibly stupid, and the magnetic and electric fields are simply the same thing, and both are transmitted by way of photons?
 
 
grant
19:01 / 11.06.03
Photon = light (from photo, a form of phos, the Greek word for "light".)

Electron = electromagnetism (from elektron, the Greek word for amber - which the Greeks would rub to generate static electricity.)

If you wrap an electrified wire around a hunk of iron, it becomes a magnet, so I'd guess the fields are the same...

Whether or not there's an actual difference between an electron and a photon is a whole 'nother thing.
 
 
—| x |—
20:01 / 11.06.03
“And, of course there is wave-particle duality, that says electrons exhibit behaviour of both waves and particles.”

I was under the impression that this wave-particle duality was applicable to any and all things, but it is more that most often things interact with one and other (are commonly measured or observed in ways) that produce particle-like phenomena or characteristics over wave-like ones.

“…so if you did get to the speed of light the universe would end.”

Hmm…I’m not so sure it is as “apocalyptic” as you make it sound, Q. As far as I’m aware it is not so much that the universe ends per se, but more that all the light in the universe (thus, what can be seen of the universe) becomes compressed to a point at light speed—time stops moving. However, we could decelerate from light speed (if we could go light speed), and the universe would re-emerge out of the point of light that was what we could see of the universe when we were traveling at c.

Another fundamental difference between Classic mechanics and Relativity is that in the Classical picture, like Q notes about a “clockwork universe,” it is assumed that there is a central point to space and that there is a universal clock ticking away a constant universal time. Put differently, in the Classic picture there exists an absolute frame of reference. Relativity undermines this and says that there is no absolute frame of reference, but only relative ones. Thus, on the Classic picture events that happen simultaneously appear that way to all observers; however, on a Relative interpretation events that happens simultaneously will appear so only to certain observers in certain frames of reference while to other observers one event will precede the other.
 
 
—| x |—
20:10 / 11.06.03
WRT so-called "fundamental forces":

Like has been noted there was a time when electricity and magnetism were seen as separate forces, but have been unified in a more complete theory. Now, it seems to me that there has also been research towards showing that the electromagnetic force unites with the weak force at higher temperatures-energies to become the electroweak force. It is also theorized that at even higher (much, much higher) energies that this unites with the strong force to give the Strong-electroweak force. The grail, like has been noted, is to show that gravity will unify with this strong-electroweak force.

However, I don't think QM has the resources to do this since gravity is seen as a function of a so-far undiscovered particle called the graviton. I think that Relativity with gravity being curved and bent space is a better way to understand gravity, but this is irreconcilable with the QM view. Sigh, send in the strings!
 
 
tom-karika nukes it from orbit
20:59 / 11.06.03
I beleive that we cannot currently reach the energies required to make the electroweak force in quantities large enough to observe within the error of the instrumentation used, but it has been observed, unreliably. I'll see if I can get a link, but I may be some time... Seems like we need a bigger particle accelerator.

On the question of graviton observation, or at least measurement of their speed, there is a thread here. The problem with gravity is that it's such a weak force, we can't measure it at levels small enough to see an individual 'quanta'. Photons, on the other hand can be counted- you can detect individual gamma ray photons arriving from the background radiation with a simple Geiger-Muller tube.

Posted by grant:

Whether or not there's an actual difference between an electron and a photon is a whole 'nother thing.

Well the fundamental difference is that the electron has a measurable mass and a charge and an energy, whilst the photon has only energy. But electrons can be seen to obey the same mechanical model as photons, as they are so small. So you can diffract electrons just like photons. Somewhere I have an old New Scientist article about diffracting big molecules like Bucky Balls to some extent.

Oh, and did you know that if I were to drive a double decker bus through the Marble Arch at 10 billion m/s, it would diffract to the point of being a whole ten centimetres wider? (Forget that the bus would be violating relativity, this is just to demonstrate how badly quantum mechanics scales up.)

Right, another question- If photons (and electrons...) can exist everywhere at the same time (in order to obey the rule that they try all paths between points to find the best way of getting there) then how come we need more than one?
 
 
tom-karika nukes it from orbit
21:09 / 11.06.03
I've got some links: electroweak force link, and a good link about detecting the Higgs Boson.
 
 
Quantum
08:09 / 13.06.03
Gravitons are incredibly difficult to detect, but Gravity Waves might be easier (and are the cool new theory on the block I think)

If photons (and electrons...) can exist everywhere at the same time (in order to obey the rule that they try all paths between points to find the best way of getting there) then how come we need more than one?

Wah! My brain! We don't need more than one, and it's possible there is only one photon. Because they are time symmetrical, the photon could zoom from the sun to your eye back to the sun (backwards in time), to Alpha Centauri and back, etc. as well as potentially existing everywhere at once.
Although photons do get absorbed when they hit dark things, so maybe that's why we need more than one.
And they're waves too so we could say they're all one wave...
My head hurts.


NOT because the light bounces off them and affects them but because our consciousness affects the outcome directly - Quantum
Given the nature of the thread, it should be pointed out that this is but one interpretation of QM. I don't *think* it is standard amongst physicists.

Yeah, it's standard- the collapse of the wave function is an effect of observation (Schroedingers cat in a box)

It also proved the existence of sixteen dimensions (at least) that Einstein theorised

Are you sure you mean "proved" here? I'm not sure that that statement would be uncontroversial in physics circles.

I was wrong here, memory failed me. It was 11 dimensions, but I did mean proved although perhaps 'found evidence for' might be better- the Math implies eleven d. Also I might be wrong twice, Einstein may have done that math.
 
 
—| x |—
08:28 / 13.06.03
This 11 dimensions, I believe, is required for certain formulations of string theory, yes? Other formulations use 10 dimensions, and there might be some theories that rely on less. As far as I am aware, yes, these dimension exist as a product of the maths; however, they are also required in an attempt to unify these various forces we observe.

I was also under the impression that E was concerned with four dimensions, and that Minkowski helped out with much of the math.

As for there being only one photon, a friend and I used to talk about this a long time ago--we would speculate about there being this one photon that was chasing itself around two poles ("light-dark," "positive-negative," etc.). As to it being absorbed when hitting "dark matter," I'd speculate that since that matter is itself the one photon, it merely absorbs and emits itself in order to a) maintain and perpetuate its manifestation as that particular piece of matter, and b) so it could continue on its timeless journey of interacting with itself through the whole of time.

Kinda' neat but I've no idea how one would go about proving this!
 
 
Quantum
10:23 / 13.06.03
Not 'Dark Matter' but dark matter, like a black sock or your retina. Which isn't made of photons, but quarks (which make protons and neutrons i.e. atomic nuclei) and electrons, bound together into atoms, combined to form molecules, which stick together to make things like socks.
Photons are little bits of light (or other EM radiation), currently physics says there's loads of different subatomic particles. The idea that there's one thing zooming back and forth in time to make up everything has to include the notion that the thing changes, or else it's an even more fundamental particle than the ones we have now.
Thing is when you get smaller than the Planck length ideas like particles get dodgy, everything seems to be a counterintuitive froth of probability. Which is one thing in a way. (I think the universe is one thing, all of the diversity we see is imposed on it by us, the notion of individual things being separate is a human fallacy. But I'll save my buddhist philosophy for the Magick)
 
 
—| x |—
17:49 / 13.06.03
Yes, that is why I put 'dark matter' in quotes because I wanted to convey that I meant things like socks and such and not theoretical "dark matter." I knew I should of merely rewritten the sentence.

Certainly contemporary physics recognizes a virtual zoo of particles; however, these might turn out to be the differing sides of a photon depending on its velocity, its relations to itself at a particular time and location in spacetime, the curvature of the space it traverses from t1 to tx, etc.. I mean, what do we know about photons really...

[an aside for you Q, if you have a somewhat "Buddhist" philosophy, then I am having an even harder time understanding your difficulties in the thread about "things" since the "things iff relations" view I am developing is heavily influenced by a Buddhist outlook on phenomena!]
 
 
Lurid Archive
17:33 / 14.06.03
NOT because the light bounces off them and affects them but because our consciousness affects the outcome directly - Quantum

Given the nature of the thread, it should be pointed out that this is but one interpretation of QM. I don't *think* it is standard amongst physicists.

Yeah, it's standard- the collapse of the wave function is an effect of observation (Schroedingers cat in a box)

Yes and no. You are equating observation with consciousness in a way that may be valid, but has its problems and is certainly not mainstream amongst physicists. If it were, one would have that the universe didn't hve any wave function collapse before humans arrived - so stars couldn't work, for instance. Perhaps one can fix this by the existence of a conscious being that observes things now and again. Regardless, it isn't what physicists accept. From wikipedia again,

However, in contrast to some incorrect popularizations of quantum mechanics, it is not believed that the measurement process involves consciousness. It can be demonstrated that the collapse of the wave function occurs when the wave function encounters a non-conscious measurement instrument. In fact, this characteristic of quantum mechanics has practical uses in quantum cryptography.

There are definitely unanswered questions, and I'm not saying I have the answers, merely that one should be careful in delineating the "facts".

Similarly, with the 11 dimensional stuff. As far as I can tell, cosmology is largely wild speculation.
 
 
—| x |—
19:25 / 15.06.03
“Similarly, with the 11 dimensional stuff. As far as I can tell, cosmology is largely wild speculation.”

I think this isn’t quite correct. Yes, eleven dimensional theories might be used for some cosmological purposes; however, this is not merely the only use. It seems to me that various formulations of string theory are jockeying for the position of “the physics of tomorrow.” This means that it might be the case that “11 dimensional stuff” (or 10 dimensional stuff, or 8 dimensional stuff or etc.) will be the cornerstone of upcoming contemporary physics and not merely a device in some cosmologies.
 
 
Quantum
10:42 / 16.06.03
Observing a phenomenon does not require consciousness (instruments can do it), but what I said was "..our consciousness affects the outcome directly". The wave function is collapsed not ONLY by conscious observation, but by things INCLUDING conscious observation. That's accepting in mainstream physics isn't it?

cosmology is largely wild speculation.
That's certainly true. I think because we're stuck in one place with a fixed view of things colossally far away, it's difficult to say much about them without deducing, inferring and assuming rather a lot from very little information.
 
 
Panic
14:23 / 16.06.03
I swear I'm not planning something.

I'm just curious. This was prompted by a movie scene in which someone tosses a toaster into a jacuzzi.

Water conducts electricity, yeah? So, if the current were strong enough, could it be conducted through a much, much larger volume of water with sufficient force to affect organisms in the water? Or is there some voltage (or amperage, I'm never sure) to volume ratio at which the current begins to dissipate?

No, seriously, I'm not planning something.
 
 
grant
14:54 / 16.06.03
Someone else can give a more specific answer, but basically, you'll get a spherical volume of electrified water that's more intense the closer to the source you get, unless it finds something conductive to ground into, in which case it'll form a nasty ol' circuit. I remember that from scuba classes (lightning is a big deal in Florida beach dives).
 
 
Bomb The Past
15:04 / 16.06.03
Water conducts electricity, yeah?

'Fraid not, water on its own doesn't conduct electricity. But before you start installing the aforementioned toaster in your jacuzzi, bear in mind that salt water is conductive and humans, being sweaty creatures might get fried as a result if they stray too close. AFAIK, salt water is a pretty shitty conducter though, so just adding loads of salt to the water probably won't work either.
 
 
Less searchable M0rd4nt
15:55 / 16.06.03
It's quite true that pure distilled water is an insulator and does not conduct electricity. However, most water just isn't that pure; even the water that comes out of your tap contains plenty of impurities such as dissolved minerals, chemicals involved in water treatment, et cetera. Electrons can hitch a ride on these impurities, allowing current to flow. That's why you should't take radio into the bathroom while you're bathing or touch electrical sockets with wet fingers. As Dead Flower points out, the minerals naturally present in human sweat help condution. Electricity and water are a lethal combination.

Even a body of water such as a lake will conduct electricity, as illustrated by the rather unsporting practice known as telephoning fish. Here the author describes how the elecrical generators found in old hand-cranked telephones can be used to stun fish:

...these old phones were being thrown away and resourceful people tried to find ways to unutilized the parts in other ways. One of the most famous ways is to shock or stun fish. This was done by attaching 2 wires to the Mag and dangling the wires off both sides of the boat while the Mag was being cranked. This would not kill the fish but temporary stun them. Sometimes the fish would wake right up as soon as you quite cranking the Mag. As the fish were stunned they would float to the top of the water and someone could count or even scoop up the fish.
 
 
Smoothly
10:21 / 23.06.03
Either this thread has been hijacked, or it should be moderated to be called 'Rather intelligent science questions'. People are asking about unified forces, wave/particle duality, relativity, fucking Schrodinger!.....and still the iron filings fly.
It's not very encouraging you know.

So to get back on track, somebody tell me: how do fizzy drinks get fizzy? If you bubble a gas through a liquid, how does some of it get 'stored' and released a few little bubbles at a time, rather than all at once?

Put even more stupidly, why does a freshly opened can of coke go 'Fizzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz....', rather than 'Flubble'?
 
 
Quantum
12:19 / 23.06.03
High pressure CO2 dissolves into the liquid, so as long as it stays in a pressurised container it'll stay dissolved. As soon as the pressure outside the liquid decreases (you open the can of pop) the CO2 forms bubbles around the irregularities in the can and makes streams of bubbles (look in a pint of lager to see this happen, the streams of bubbles come from the same spot on the bottom of the glass).

It's the same principle as rain or snow actually, except upside down. Stuff condenses out of a medium (fizz from pop, rain from clouds) and falls down/floats up.

If you chuck a sweet into someone's beers it'll fizz like a bastard and then go flat, because the CO2 has something to condense around (like raindrops condensing around bits of dust). Sherbet or sugar is especially effective in a bottle of beer (whoosh!)
 
 
Smoothly
14:08 / 23.06.03
Cheers Q.
I didn't know that water vapour in the air needed dust to coalesce into rain (I assumed it had to do with hitting the right temperature or pressure or something) so while that isn't the ideal analogy for me in this case, you've educated me beyond the call of duty.

So dissolved gases change state in contact with little particles in the liquid, or on the container, and turn into little bubbles. And so lots of little particles, like sugar, make lots of little bubbles. I assume that big particles, like marbles, don't create big bubbles. Is there a simple reason why Dissolved Gas + Small Particles = Bubbles?

Also, why does shaking a can, or clunking the top of an open beer bottle with the bottom of another, have such a dramatic effect? Does it energise the dissolved gas somehow - make it more inclined to condense?
 
 
Warewullf
12:55 / 24.06.03
Excellent thread! Me needy help!

I'm working on a story and I need a bit of technical help. I've tried researching this but just can't find the answer.

Scenario:
A jeep, buried in snow up to the roof. The sunroof open so there is air getting in. It's absolutely fucking freezing outside. Is it hot or cold in the jeep?
(I'm thinking there may be an igloo effect, but I'm not sure.)

What if the jeep's heater is on? Would it be able to work under that much snow?
 
 
grant
13:59 / 24.06.03
On why shaking a can makes the fizz go all at once: because agitating a supersaturated solution will make the solute come out. I think.
Which is sort of a fancy way of saying that if you stir a soda, it'll bubble more. Duh.
So, to be less tautological, the same thing will happen with, say, iced tea with way too much sugar in it. You heat up the tea, dump in sugar until no more will melt into it (supersaturated solution), then cool it down. Hit sharply with something, and the sugar will drop out of solution until you've reached the maximum sugar level for that temperature.

As for why that happens, you'll have to get into Brownian motion and all that molecular stuff. Hotter or more-pressurized liquids will dissolve more stuff than cool, low-pressure liquids because the molecules move around more, so they stick onto other molecules more.

--------------

On the size of bubbles: this seems to depend on the density/viscosity of the liquid... we used to have this little device for charging your own sodas at home. It used similar CO2 cartridges to the kind that BB guns use. If you carbonated plain water, you'd get club soda (big bubbles), but if you carbonated water + flavor syrup, you'd get little bubbles. Actually, now that I think of it, you can see the same thing happen when you do one of my favorite things: get a can of that liquid fruit juice concentrate and a bottle of club soda and make yerself some cran-raspberry soda. The bubbles go from big to small as the syrup dissolves in the liquid.

By the way, in the case of beer (and some kinds of soda, like home-brewed ginger beer), the compressed CO2 comes from yeast, not canisters of gas. The yeast eats sugar and, in essence, farts. "Creates gas as a byproduct of digestion" is the nice way to put it. The bottles the beer is brewed in have to be really solid, airtight things or else the beer will be flat.

---------------

In the jeep, it will be warmer than the air outside, because you've got a few heat sources (human bodies) under a layer of insulation (snow, and the jeep itself). Whether or not the heater will work is really a question for mechanics, but I'll venture a guess... I don't think jeep heaters are electric; I think they use the radiator/manifold to warm the inside of the vehicle. Which means that the engine would have to be running to use the heater.

There are two problems with this in your scenario --
1. The snow is up to the roof, and it's basically airtight (I think - I'm more familiar with cars than I am with snow). It would probably plug up the exhaust, keep new air from getting to the air intake, and the engine wouldn't run, just backfire and stall out.
2. The snow, up to roof but not airtight enough to choke the engine, would make a nice chamber to collect carbon monoxide. After a couple hours, anyone below roof level would be dead from CO poisoning.
This would be gotten around if the jeep had an electric heater, which would run until the battery died. Might be possible to run the engine for a few minutes every hour to recharge the battery, but it wouldn't be easy, and there'd still be the risk of monoxide poisoning stretched out over time.
 
 
grant
14:01 / 24.06.03
Also, if the sunroof is open all the way, you're going to lose all your heat. It rises, y'know.
 
 
Linus Dunce
19:29 / 24.06.03
I don't think any autos have electric heaters, do they? Though some have electrically-heated seats, so maybe they do. But you'd need to keep the engine running all the same because heating elements use a lot of juice, more than you could recharge in a few minutes' fast running. You could maybe solve the carbon monoxide problem and air intake problems with some hosepipe that happened to be to hand, but I think you'd have problems keeping the radiator/cooling fan clear of snow to stop the engine overheating and seizing up in its own little igloo.

I reckon your best bet is to wrap the characters in whatever blankets and stuff they have to hand and blocking the sunroof as much as possible but with a gap for air circulation. You wouldn't need a large hole to breathe -- people manage fine normally in traffic jams with the windows all rolled up.
 
 
Quantum
07:48 / 25.06.03
In a traffic jam the engine is running the air conditioning or fans, and the vents aren't full of snow. The engine won't work and the ventilation won't work because the jeep is buried in snow, they'll have to open the sunroof a crack for sufficient ventilation.
The igloo effect might work, although I reckon they'll be pretty cold because they don't have a fire (unless they start one?) and the metal frame of the car will conduct heat away quickly.
I reckon have the characters get cold and start a fire using whatever is to hand, then choke on the plastic fumes and have to put it out and stay cold. Although you might not be so cruel..
 
 
Warewullf
11:12 / 25.06.03
Excellent help, guys, thanks!

I think i'll go with the no heater/wrapped in blankets/small airhole idea.
 
 
Smoothly
11:46 / 25.06.03
Good work on the fizz questions grant. I reckon I understand now. And I'm going to try tapping sugar out of a super-saturated solution, you can fucking count on it.
 
 
knickers
18:58 / 25.06.03
Way back when I was forced to do GCSE Physics, my teacher gave us a crap explanation of this, but none of us could understand it: why can you hear sounds coming through a wall, but can't see light coming through?
 
 
tom-karika nukes it from orbit
20:35 / 25.06.03
Sound and light are completely different.

Light is an electromagnetic radiation. It consists of photons, particles with energy and no mass. If they hit the wall, they interact with the wall, bouncing off it or heating it up. Some photons DO go straight through the wall, things like radio-frequency photons are good for this.

Sound is vibrating molecules. Molecules vibrating in the air become vibrations in the wall, and then vibrations in the air on the other side. This is with normal every day matter, with mass and made up of atoms that move around. No photons involved

So sound and light have very little to do with each other, except that we usually model them both as a nice curvy waves.
 
 
grant
20:53 / 25.06.03
The first part of the answer is: you *can* see light through it, if it's a wall made of glass or horn or thin plastic or cloth.

The way I understand it, the second part of the answer has to do with the size of sound waves as compared to the size of light waves (the amplitude), with both being compared to the size of them molecules the wall is made of. Sound waves are big enough to make the molecules move... thus, to be carried across those molecules into the next room. Light waves are much, much smaller. Like, if you zap a tube half-filled with water with a loud, low pitched sound (volume=amplitude, pitch=frequency), you can actually see the waves travel along the tube. Lightwave amplitudes are measured in nanometers.

Hmm. It might also have to do with the *kind* of waves that make up sound as opposed to light.



It's a compression wave, carried through molecules (the little dots on that image). Light is carried by, well, subatomic particles - photons. I have no idea if ideas like "compression" make sense at that level.

Somebody else can probably give a more accurate explanation.
 
 
grant
20:57 / 25.06.03
Geez, somebody already did.

Sigh.
 
 
knickers
21:41 / 25.06.03
Thanks. I pretty much understand now.
:-)
 
  

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