1261
Physics, Astronomy & Cosmology / Re: Can we put an end to the nonsense of "duality"?
« on: 21/11/2015 23:45:46 »
You are, literally, beginning to see the light.
The following users thanked this post: Zer0
Show Posts
This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
1262
Physics, Astronomy & Cosmology / Re: What would happen in this scenario?
« on: 15/11/2015 09:14:41 »
If you double the force, you double the acceleration, regardless of the source of that force. Newton, I, "Principia", 1713 (Cambridge).
The following users thanked this post: jeffreyH
1263
Technology / Re: Negate the expansion of freezing water using small, compressible balls
« on: 12/11/2015 22:31:52 »
We do this to absorb the thermal expansion of oil in x-ray tube assemblies. The "absorber" is a small rubber bellows or ball filled with nitrogen that compresses as the oil expands.
This might work in principle with freezing water but you might need several balls as the water will freeze from the top downwards and thus trap a floating ball.
Alternatively put the water in a flexible bag inside a metal or glass bottle.
This might work in principle with freezing water but you might need several balls as the water will freeze from the top downwards and thus trap a floating ball.
Alternatively put the water in a flexible bag inside a metal or glass bottle.
The following users thanked this post: McKay
1264
Physiology & Medicine / Re: What makes us human?
« on: 12/11/2015 13:50:03 »
We are very little different from any other mammal. There is a presumption of limited interfertility, which partly defines a species (though some politicians are alleged to have tried mating with suidae, presumably to improve the manners and intellect of the political class) but the more obvious characteristic is the desire to record things that are too trivial to remember: in this, we seem to be unique.
The following users thanked this post: Jingle Jangle
1265
Physics, Astronomy & Cosmology / Re: Is the Copenhagen Interpretation correct interpretation of quantum mechanics?
« on: 12/11/2015 09:40:42 »
Try full screen and freeze frame. You will see that the particle never touches the divider. Indeed it can't, because it is being carried by the wave, not the other way around, and if the wave amplitude was zero between the particle and the divider, the particle would fall into the "soup".
It's very pretty, but it's just mesoscopic fluid dynamics and nothing to do with quantum physics.
It's very pretty, but it's just mesoscopic fluid dynamics and nothing to do with quantum physics.
The following users thanked this post: jeffreyH
1266
Physics, Astronomy & Cosmology / Can we put an end to the nonsense of "duality"?
« on: 10/11/2015 09:28:43 »
Consider a visible photon, emitted from a single event. Its energy is about 2 eV.
Now consider a wave spreading out from a point source. The energy density at any point a distance r from the source must be E/4πr2 eV/m2 where E is the original energy of the source event.
Now we detect our photon, a light year away from the star that emitted it. Ignoring a bit of red or blue shift, the detection event releases 2 eV. So if "wave function collapse" has any real meaning, all the energy that was dissipated over an area of 4π (light years)2 has instantaneously and simultaneously condensed on my detector. This means that some energy has travelled 2 light years in no time at all, and arrived in the right place, with no prior warning or loss.
So let's pretend that relativity is wrong and there is no upper limit to the speed at which information can travel. We still have an anomaly because some of the energy travelled only a very small distance, some travelled 2 light years, and yet it all arrived at the same time. How did it know how fast to travel, let alone where to go?
The simple fact is that "duality" is completely illogical. The world behaves as it does and we have to choose an appropriate model to predict it, but the model is not the reality, any more than you can grow potatoes on a map of Ireland.
Now consider a wave spreading out from a point source. The energy density at any point a distance r from the source must be E/4πr2 eV/m2 where E is the original energy of the source event.
Now we detect our photon, a light year away from the star that emitted it. Ignoring a bit of red or blue shift, the detection event releases 2 eV. So if "wave function collapse" has any real meaning, all the energy that was dissipated over an area of 4π (light years)2 has instantaneously and simultaneously condensed on my detector. This means that some energy has travelled 2 light years in no time at all, and arrived in the right place, with no prior warning or loss.
So let's pretend that relativity is wrong and there is no upper limit to the speed at which information can travel. We still have an anomaly because some of the energy travelled only a very small distance, some travelled 2 light years, and yet it all arrived at the same time. How did it know how fast to travel, let alone where to go?
The simple fact is that "duality" is completely illogical. The world behaves as it does and we have to choose an appropriate model to predict it, but the model is not the reality, any more than you can grow potatoes on a map of Ireland.
The following users thanked this post: Zer0
1267
Physics, Astronomy & Cosmology / Re: Is the Copenhagen Interpretation correct interpretation of quantum mechanics?
« on: 08/11/2015 18:30:12 »The following image shows the interference pattern build up over time for electons.The key here is "build up over time". A single electron can't provide an interference pattern because, unlike a wave, it is indivisible. What we actually detect, whether electrons or photons, is individual particles hitting the detector with a spatial distribution that looks like wave interference.
The following users thanked this post: jeffreyH
1268
Physics, Astronomy & Cosmology / Re: Why don't an atom's electrons fall into the nucleus and stick to the protons?
« on: 08/11/2015 13:41:09 »
A neat reference- particularly as it supports my preferred use of "indeterminacy" for Heisenberg's principle.
I still think it better to start from the observation that atoms have a finite diameter, therefore you can't assume that classical electrostatics will model it.
I still think it better to start from the observation that atoms have a finite diameter, therefore you can't assume that classical electrostatics will model it.
The following users thanked this post: jeffreyH
1269
Physics, Astronomy & Cosmology / Re: Is the Copenhagen Interpretation correct interpretation of quantum mechanics?
« on: 07/11/2015 01:00:29 »Quote
According to the Copenhagen interpretation, physical systems generally do not have definite properties prior to being measured,No. That is a misleading formulation. It is true that we don't know anything about a particle until it interacts with another particle. The fact that I don't know whether you are wearing a hat until I see you, has nothing to do with whether you are or are not wearng a hat: I can't draw an accurate picture of you until we have met, but that meeting doesn't determine your appearance because you must have put the hat on before we met.
Quote
and quantum mechanics can only predict the probabilities that measurements will produce certain results.Yes
Quote
The act of measurement affects the system,Yes
Quote
causing the set of probabilities to reduce to only one of the possible values immediately after the measurement. This feature is known as wavefunction collapse.No. What happened is what you measured. Waveform collapse is a mathematical model of what happens.
The following users thanked this post: jeffreyH
1270
Physics, Astronomy & Cosmology / Re: What is the largest possible rest mass of the photon?
« on: 07/11/2015 00:55:26 »
Science is the recursive application of the algorithm "observe, hypothesise, test". Philosophy is something else. It usually involves an incomplete observation, a wholly irrelevant hypothesis, and an excuse to do something bizarre or evil. Testing and recursive refinement are beneath the lofty intellect of a philosopher, which is why they tend to flock with those other arrogant purveyors of ignornace, priests and politicians. If you allow philosophy to infect science, you end up with such perversions as Nazi science, Lysenkoism, Maoism, ruin and starvation. Evolution is a scientific observation, creationism is a philosophy. There is no scientific justification for beheading infidels, but a powerful philosophy can sanctify it.
The overweening arrogance of philosophers is apparent from Evan's posting. As is the fatuous nature of philosophy
The overweening arrogance of philosophers is apparent from Evan's posting. As is the fatuous nature of philosophy
Quote
Photon, Elementary particle, Particle physics, Physics, Natural science, Science, Knowledge, Awareness, Consciousness, Quality (philosophy), Philosophy.It all makes sense until you get to "consciousness", a term which is never defined by its users: everything thereafter appears to derive its place in the thread, from a meaningless word. Philosophically, a photon must be a wave or a particle, so the properties of electromagnetic radiation depend on some notion of duality and observer-dependence...what utter rubbish! We scientists use the term photon to denote the cause of a number of linked phenomena: it doesn't "have to be" anything other than itself, and we admit that we don't have a unique mathematical description of all its properties. That is a far more mature, and far less arrogant and athropocentric way of looking at the universe.
The following users thanked this post: jeffreyH
1271
General Science / Re: Does UVC light sterilize only the surface?
« on: 06/11/2015 08:44:24 »
UVC is primarily a surface sterilant, though it can be used to sterilise thin layers of circulating water.
We use heavy cotton overalls for protection against UV therapy sources: penetration through a lab coat or jeans is almost negligible. Since any pathogens in a pillow will be distributed throughout the filling (where it's warm and moist) you really need steam, bleach, gas or gamma radiation, to have any useful effect.
Any sterilant (including UVC) will be extremely dangerous if it is effective - you are made of the same stuff as bacteria, but they are a lot tougher. Don't try any of this at home!
We use heavy cotton overalls for protection against UV therapy sources: penetration through a lab coat or jeans is almost negligible. Since any pathogens in a pillow will be distributed throughout the filling (where it's warm and moist) you really need steam, bleach, gas or gamma radiation, to have any useful effect.
Any sterilant (including UVC) will be extremely dangerous if it is effective - you are made of the same stuff as bacteria, but they are a lot tougher. Don't try any of this at home!
The following users thanked this post: earthliver
1272
Physics, Astronomy & Cosmology / Re: Can a photon be length contracted?
« on: 04/11/2015 22:31:04 »
If an object has no existence at rest, it cannot contract from its rest length.
The following users thanked this post: jeffreyH
1273
Chemistry / Re: Does burning candles improve air quality?
« on: 30/10/2015 16:18:56 »
No. High quality air contains only oxygen and nitrogen with a hint of water and CO2. Burning anything increases CO2, decreases O2, and adds soot and volatile materials to the mix, none of which is good for you.
"Cooks' candles" absorb strong odours but you are just substituting one chemical pong for another.
"Cooks' candles" absorb strong odours but you are just substituting one chemical pong for another.
1274
Physics, Astronomy & Cosmology / Re: What is the largest possible rest mass of the photon?
« on: 30/10/2015 09:53:09 »
The lowest possible frequency is any number greater than zero. However as Evan says, the lowest detectable frequency depends on the length of your antenna and your patience. As the earth's magnetic field drifts and reverses every billion years or so, there's at least one known photon out there with a lower frequency than sunspots, but you'd have a tough job to find it.
The following users thanked this post: jeffreyH
1275
Physics, Astronomy & Cosmology / Re: Is there one fundamental energy?
« on: 27/10/2015 08:21:21 »1276
Physics, Astronomy & Cosmology / Re: Could you become a God by traveling at the speed of light?
« on: 26/10/2015 21:32:47 »
Could you become a God by traveling at the speed of light?
No. Or possibly Yes. But since you can't travel at the speed of light, don't waste too much time on the subject.
No. Or possibly Yes. But since you can't travel at the speed of light, don't waste too much time on the subject.
The following users thanked this post: Mohammad Alkenni
1277
Geology, Palaeontology & Archaeology / Re: When during human evolution did the first scientist appear?
« on: 25/10/2015 20:52:58 »
No. Evolution is about what the cell did next, not how it came into existence in the first place.
The following users thanked this post: chris
1278
Geology, Palaeontology & Archaeology / Re: When during human evolution did the first scientist appear?
« on: 22/10/2015 23:59:10 »
In 1983 I watched a gorilla at Chessington Zoo discover the principle of universal gravitation. He had two apples, one considerably larger than the other, one in each hand. He dropped them and noticed that they hit the ground at the same time. He repeated the test, twice, then changed hands and did it again. Perfect null experimental technique: observe, repeat, change one parameter.
On the presumption that gorillas don't read books or have much of an oral tradition of scientific knowledge, this chap discovered, by the application of best scientific practice and in the space of five minutes, what took humans several million years and and a fair bit of bloodshed. Indeed there is no historical evidence that Galileo actually did his "leaning tower" experiment, and if you read some of the bizarre submissions to this forum, it's quite clear that very few humans appreciate even the simplest principles of scientific investigation. Of course the gorilla didn't have to shake off centuries of superstition and the threat of excommunication, which gave him a huge advantage over Bruno et al.
Having seen birds, rats and chimpanzees deduce causal relationships from observation, and having marvelled at the gullibility of humans (including verbatim acceptance of garbage like Genesis) for many years, I fear that scientific thought in homo sapiens is something of a rarity compared with other species. Worse: when it appears, the herd generally tries to stamp it out, always preferring consensus and superstition to the demonstrable truth - unlike blue tits.
On the presumption that gorillas don't read books or have much of an oral tradition of scientific knowledge, this chap discovered, by the application of best scientific practice and in the space of five minutes, what took humans several million years and and a fair bit of bloodshed. Indeed there is no historical evidence that Galileo actually did his "leaning tower" experiment, and if you read some of the bizarre submissions to this forum, it's quite clear that very few humans appreciate even the simplest principles of scientific investigation. Of course the gorilla didn't have to shake off centuries of superstition and the threat of excommunication, which gave him a huge advantage over Bruno et al.
Having seen birds, rats and chimpanzees deduce causal relationships from observation, and having marvelled at the gullibility of humans (including verbatim acceptance of garbage like Genesis) for many years, I fear that scientific thought in homo sapiens is something of a rarity compared with other species. Worse: when it appears, the herd generally tries to stamp it out, always preferring consensus and superstition to the demonstrable truth - unlike blue tits.
The following users thanked this post: Ophiolite
1279
Chemistry / Re: Could a solar powered cooling system be used to collect water from the air?
« on: 16/10/2015 17:41:30 »Assume a coefficient of performance of about 2. Your 150W refrigerator can therefore shift about 300W of heat. Condensing 1 gram of water requires about 2300 joules of heat to be extracted, so you can condense 300/2300 = 0.13 gram per second. If the water content of air is about 5% you need to pass 20 x 0.13 = 2.6 gram of air per second over your condenser - about 2 liters/second. You can probably achieve this with a 2W fan, which won't impose a significant load on your power supply.
The following users thanked this post: chris
1280
Physiology & Medicine / Re: Urinating on the moon.
« on: 15/10/2015 22:58:10 »
A pee tube is built into any pressure suit intended for long-term wear. Short-term you use a nappy (diaper).
Glider pilots suffer from cold: a flight of more than 3 hours becomes a test of bladder control and moral fibre as much as airmanship. So some gliders have a venturi waste tube attached to a rubber cup (known in less PC days as the "Polish microphone" - well, it was invented in Poland) but a fighter test pilot, accustomed to having proper personal plumbing in his office suit, attached himself to a glider venturi with a transparent polythene bag. The other thing glider pilots suffer is sunburn. The experiment was well publicised in the 1970s and I don't think has been repeated.
Glider pilots suffer from cold: a flight of more than 3 hours becomes a test of bladder control and moral fibre as much as airmanship. So some gliders have a venturi waste tube attached to a rubber cup (known in less PC days as the "Polish microphone" - well, it was invented in Poland) but a fighter test pilot, accustomed to having proper personal plumbing in his office suit, attached himself to a glider venturi with a transparent polythene bag. The other thing glider pilots suffer is sunburn. The experiment was well publicised in the 1970s and I don't think has been repeated.
The following users thanked this post: chris