It doesn't matter. If the current is pulsed, it is not a constant current, and the average power will not in general be equal to the product of voltage times average current. If you don't know the actual waveform of the current and voltage in a circuit, there is no way to calculate the average power. We are so used to dealing with cases where the waveform is known--either because it's constant or because it's sinusoidal--that we forget this (or are never taught it).
Besides this, an ordinary multimeter will not give any useful information about a signal consisting of brief current pulses. It is just not designed for that. The output will not be any kind of "average" current.
The fact that this guy does not understand these issues pretty much invalidates his claims. He does not know how to measure the power consumed by his motors, and there is every reason to believe (based on thermodynamics) that the actual power consumed is greater than he claims. Until he can produce a correct power measurement, there is no reason to give his claims any further attention.
Anyway, the volts and amps at the input terminals of the motor will always equal the power input whether measured at an instant or averaged over a period. By definition!
This is simply not true. Average power is in general not equal to the product of average (or RMS) voltage and current. This works only for the special case where the current and voltage are sinusoidal and in phase.
P(t)=V(t)*I(t) holds only for instantaneous power, voltage, and current.
I am a physicist, and this is exactly correct. One does have to be careful, though, about what one means by "power" in an AC circuit. You are thinking of average power. When the voltage and current are in phase, the average power is the product of the RMS current and voltage. P(t)=V(t)*I(t), on the other hand, always holds for instantaneous power, voltage, and current.
or a stopwatch; and wait for the driving battery to go dead, then estimate based on the battery capacity
Battery capacity is not constant, independent of current. Most batteries will deliver fewer ampere-hours if the load draws higher current. One could still estimate an upper limit, of course. I bet it's way more power than he claims.
As long as he's using a constant voltage supply, the average input power can be calculated from the average current, which is what a standard multimeter will show if the current is fluctuating quickly and periodically
This statement is wrong several ways. First, you probably mean RMS ("root mean square") current, not "average current". The average current in an AC signal is of course typically zero. AC multimeters display RMS current and voltage.
Second, you cannot in general calculate average power from RMS (or average) voltage and current, even if the voltage happens to be constant and the current is somehow time-varying. The familiar P=VI formula is for instantaneous power, i.e. P(t)=V(t)*I(t). It happens that if the current and voltage are in phase (i.e. the load is purely resistive) then the average power is the product of the RMS voltage and current. This is a special case.
Third, it is not that hard to get even a good multimeter to read a time-varying current incorrectly. They are designed for low frequency signals. If your current is time varying with even moderately high frequency (e.g. >1000 Hz) most multimeters will not correctly read even the RMS current. A poor multimeter might not even give an accurate RMS current for a low-frequency but non-sinusoidal signal.
This is not the first time someone has produced a free energy device scam based on the faulty assumptions that P=VI holds for average values and a multimter always gives an accurate 'average' voltage or current, regardless of how complicated the waveform of the signal is.
What drives me crazy about this trend toward forcing users to pick "hard" passwords, is that it's all becuase of Unix's stupid 8-character maximum limitation. A long password can be both much easier to remember and more secure than an 8-character password with numbers and symbols in it.
It's worse with websites, though. Many websites copy Unix's limitation. Unfortunately, some will apparently accept a longer password during password creation, but will then reject that password when the user attempts to log in. This leads to all kinds of fun trying to remember which password you used on a given site, and whether it has to be truncated to 8 characters or not. Argh.
No, but you're assuming in your post that chamomille has absolutely no inherently soothing ingredients, that somehow it works even though it shouldn't. Few people are arguing that. A lot of "homeopathic remedies" have been studied and shown to have substantial medical evidence supporting them and how they work. Many have been studied and shown to have no medically redeeming characteristics whatsoever.
Don't confuse holistic and/or herbal medicine with homeopathy. I wouldn't have objected to including herbal medicine in the same category as acupuncture. Many herbal medicines probably do have a pharmacological effect that could be studied scientifically.
Homeopathy is something else altogether. This is essentially a magical practice in which an herbal or mineral extract is diluted repeatedly until none of the original substance remains. Adherents believe that diluting the extract with water increases its potency. A typical homeopathic dose doesn't even contain a single molecule of the original extract. Homeopathic medicine is just plain water.
Is it possible there is something going on here that science misses? Sure. Is it likely? No. It is much more likely that this is just snake oil being sold to the unwary. Worse, homeopathy has acquired an air of legitimacy through good marketing and confusion with other forms of holistic medicine (herbal supplements, etc.)
Hmmm. Would you have an easier time believing that plain water makes your son's teeth feel better because of the placebo effect?
The issue with homeopathy is that the traditional method of preparation involves diluting the original substance to the point where none of it remains. A dose of 30X homeopathic chamomile contains no chamomile whatsoever. At that dilution, you would need, on average, about 7800 gallons of solution to have just one molecule of the original chamomile extract.
I don't have a problem with the idea that chamomile might have useful pharmacological properties. I happen to enjoy chamomile tea, myself. As a scientist, however, I find it rather hard to believe that a vial of water can somehow "magically" pick up and amplify properties from chamomile in the way that homeopathy supposes.
You're definitely correct and acupuncture is a great example. You can make similar points involving homeopathy and myths involving vaccines.
Actually, no. One can make a pretty good scientific case that homeopathy shouldn't work. This is different from acupuncture where there is no clear scientific explanation for why it might work and the "traditional" explanation doesn't seem to make sense from a scientific perspective, but there might be something else going on that we don't know about.
That assumes that there is 'truth'... which may be a rather large assumption.
Actually, you're right, and that is one of the few fundamental assumptions that underlie all science. The scientific method presumes that there is actually an objective reality ("truth") that can be observed. The existence of such a thing is not and probably cannot be proven.
It is not clear in quantum mechanics that an "observer" is necessarily a conscious mind. A number of researchers are investigating just what constitutes an "observation". Many of the working hypotheses simply require the "system" being observed to become entangled in state with a sufficient amount of other stuff.
The so-called "many worlds" view gets around the whole question in another way: every possibility happens. The observer is in a state composed of a probability distribution of possibilites too, with each possible configuration of the observer entangled with the corresponding possibility of the "system". In every possible state, the observer observes a single, definite outcome. The observer is just not "in" any one of those states but is in all of them at once (with a probability distribution of course). If you are the observer, you notice nothing different from your everyday experience: every observation appears to have a definite outcome despite what I have described. (The arguments behind this approach are complicated and I cannot do them justice here.) Note that this particular description of the "many worlds" approach is not commonly used but is equivalent to the more common descriptions.
When something happens that could have had more than one outcome, only ONE of those possibilities actually occured. What quantum mechanics allows is to figure out how likely each of the possibilities is to have occured. But ONLY ONE possibility has occured whether anyone observes it or not.
This is certainly not the conventional interpretation of quantum mechanics among physicists. What you propose would be a hidden variable theory. It has been proven by some rather famous theoretical and experimental work that the only way a hidden variable theory can be compatible with the observed data is if it is non-local, i.e. it allows particles to interact instantaneously no matter how far apart they are. For various reasons this is not a popular idea with physicists. It doesn't agree well with Relativity, and tends to produce "inelegant" theories that don't work any better than conventional quantum mechanics.
The conventional interpretation is that when quantum mechanics predicts a probability distribution of possible results, it is not meaningful to talk about only one of those possibilities having occurred, in the absence of an observation. Opinions differ on whether an observation actually causes the system to "collapse" into one of the possible states, and what the exact definition of "observation" is.
NB: an "observation" does not necessarily have to involve a conscious mind.
A green laser is much more visible than a red one because your eye is MUCH more sensitive to green light than it is to red light. ALL laser pointers should be green.
The only cool property I can think of for a blue laser is that due to its higher frequency the beam can be focused more tightly, allowing more dense optical storage, etc. Someday soon we will use enhanced DVD's that are read by a blue laser diode.
I spent a lot of time when I was 6-12 years old reading my parents encyclopedia's and old college textbooks from cover to cover. I can still recall a lot of things (over 20 years later) that I read when I was a kid that have stuck with me, without further exposure or reinforcement.
Your children will spend a lot of time surfing the net, and will learn and retain just as much as you did (maybe more).
The "tea is different!" confusion generally comes up because caffeine can also be called theine -- it's the same chemical, though.
One also occasionally encounters 'guaranine' as an ingredient in trendy fruit juice cocktails. This is just another name for caffeine--named after the guarana berry which naturally contains caffeine.
Do you really have any concept how powerful a laser it takes to even make something warm, much less be "dangerous" to anything other than your eyes? We're talking LASER DIODES here, not xenon/argon lasers.
Do you really have any concept how powerful a laser it takes to project a large raster-scanned image on a screen, that is bright enough to see in a lit room?
A few watts, properly focused, is easily enough to burn combustible materials (not to mention eyes).
Granted it may still be dangerous to the human eye, whether it's scanning or not, but so are laser pointers, and they're a bit easier to aim at someone's eyes.
Personally, I think most of the laser pointers on the market should be illegal. Most of them are class III lasers, easily able to damage a person's eye. Not something that should be in the hands of children, anyway.
Yeah, because THAT's not an unbelievable, overly elaborate way of trying to be malicious.
I'm not worried Al Queda is going to attack the Empire State Building with modified laser projectors strapped to sharks. I'm more worried about what a teenager with a soldering iron could do...
Are you a James Bond Supervillain or something?
No, just a laser physicist. But thanks for asking. Bwahahaha.
There are blue laser diodes on the market now too, I believe. They're probably still too expensive.
I don't actually expect laser projection displays to go anywhere. The advantage of a laser for projection is its high brightness (intensity in a small area). That's great for vector display where you want to "draw" bright lines. When you use a scanning laser for a raster display you lose this advantage, though. You need the same amount (intensity) of light with a laser as you would with ordinary projection. Unless the laser is more energy efficient than the ordinary projector, you're better off with the latter.
There are also safety/legal issues with laser projection. Any laser bright enough for a large projection display is dangerous if it stops scanning. The projectors of course have interlocks that shut off the laser if the raster scan jams or stops, but such a system could fail or be defeated by someone with malicious intent.
Jimbo Wales (founder / benevolent dictator of Wikipedia) was recently approached by a major publishing company about the possibility of a printed version of Wikipedia.
He should read up on what happened to Eric Weisstein's Mathworld website. In short Weisstein licensed a publisher to produce a printed "snapshot" of the website. After the book came out the publisher sued him and had his web site shut down for a year because it was infringing the book's copyright.
They understand the physics behind the overall rate of expansion of the universe, or at least they think they do. Knowing the current rate of expansion and its derivative is probably sufficient to predict the future outcome, assuming the theoretical model is correct. Of course, there are some questions about the basic model and it is not clear how they will be resolved in the end.
The guy who was high bidder this morning at least had among his past purchases a pilot's carry-on bag, a wooden model of a twin engine Cessna, and some sort of "pilot training on CD" software.
Interesting point. I wonder if it's legal to build a Faraday cage inside the walls of your theatre to block cell phone signals. You're not actually jamming anything, after all...
Are you sure they didn't just post a copy of the bill that fooled the cashier? Who would be dumb enough to stick an actual counterfeit that was good enough to fool a cashier up in a place where someone could just take it?
Could be Soft Errors caused by Alpha particles though - depends on the technology used in the flash - unlikely, but possible...
Why alpha particles? Alpha radiation is really easy to block. I find it hard to believe that any would penetrate the shielding around the electronics, much less the electronics themselves.
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Besides this, an ordinary multimeter will not give any useful information about a signal consisting of brief current pulses. It is just not designed for that. The output will not be any kind of "average" current.
The fact that this guy does not understand these issues pretty much invalidates his claims. He does not know how to measure the power consumed by his motors, and there is every reason to believe (based on thermodynamics) that the actual power consumed is greater than he claims. Until he can produce a correct power measurement, there is no reason to give his claims any further attention.
This is simply not true. Average power is in general not equal to the product of average (or RMS) voltage and current. This works only for the special case where the current and voltage are sinusoidal and in phase.
P(t)=V(t)*I(t) holds only for instantaneous power, voltage, and current.
I am a physicist, and this is exactly correct. One does have to be careful, though, about what one means by "power" in an AC circuit. You are thinking of average power. When the voltage and current are in phase, the average power is the product of the RMS current and voltage. P(t)=V(t)*I(t), on the other hand, always holds for instantaneous power, voltage, and current.
Battery capacity is not constant, independent of current. Most batteries will deliver fewer ampere-hours if the load draws higher current. One could still estimate an upper limit, of course. I bet it's way more power than he claims.
This statement is wrong several ways. First, you probably mean RMS ("root mean square") current, not "average current". The average current in an AC signal is of course typically zero. AC multimeters display RMS current and voltage.
Second, you cannot in general calculate average power from RMS (or average) voltage and current, even if the voltage happens to be constant and the current is somehow time-varying. The familiar P=VI formula is for instantaneous power, i.e. P(t)=V(t)*I(t). It happens that if the current and voltage are in phase (i.e. the load is purely resistive) then the average power is the product of the RMS voltage and current. This is a special case.
Third, it is not that hard to get even a good multimeter to read a time-varying current incorrectly. They are designed for low frequency signals. If your current is time varying with even moderately high frequency (e.g. >1000 Hz) most multimeters will not correctly read even the RMS current. A poor multimeter might not even give an accurate RMS current for a low-frequency but non-sinusoidal signal.
This is not the first time someone has produced a free energy device scam based on the faulty assumptions that P=VI holds for average values and a multimter always gives an accurate 'average' voltage or current, regardless of how complicated the waveform of the signal is.
It's worse with websites, though. Many websites copy Unix's limitation. Unfortunately, some will apparently accept a longer password during password creation, but will then reject that password when the user attempts to log in. This leads to all kinds of fun trying to remember which password you used on a given site, and whether it has to be truncated to 8 characters or not. Argh.
Don't confuse holistic and/or herbal medicine with homeopathy. I wouldn't have objected to including herbal medicine in the same category as acupuncture. Many herbal medicines probably do have a pharmacological effect that could be studied scientifically.
Homeopathy is something else altogether. This is essentially a magical practice in which an herbal or mineral extract is diluted repeatedly until none of the original substance remains. Adherents believe that diluting the extract with water increases its potency. A typical homeopathic dose doesn't even contain a single molecule of the original extract. Homeopathic medicine is just plain water.
Is it possible there is something going on here that science misses? Sure. Is it likely? No. It is much more likely that this is just snake oil being sold to the unwary. Worse, homeopathy has acquired an air of legitimacy through good marketing and confusion with other forms of holistic medicine (herbal supplements, etc.)
The issue with homeopathy is that the traditional method of preparation involves diluting the original substance to the point where none of it remains. A dose of 30X homeopathic chamomile contains no chamomile whatsoever. At that dilution, you would need, on average, about 7800 gallons of solution to have just one molecule of the original chamomile extract.
I don't have a problem with the idea that chamomile might have useful pharmacological properties. I happen to enjoy chamomile tea, myself. As a scientist, however, I find it rather hard to believe that a vial of water can somehow "magically" pick up and amplify properties from chamomile in the way that homeopathy supposes.
Actually, no. One can make a pretty good scientific case that homeopathy shouldn't work. This is different from acupuncture where there is no clear scientific explanation for why it might work and the "traditional" explanation doesn't seem to make sense from a scientific perspective, but there might be something else going on that we don't know about.
Actually, you're right, and that is one of the few fundamental assumptions that underlie all science. The scientific method presumes that there is actually an objective reality ("truth") that can be observed. The existence of such a thing is not and probably cannot be proven.
The so-called "many worlds" view gets around the whole question in another way: every possibility happens. The observer is in a state composed of a probability distribution of possibilites too, with each possible configuration of the observer entangled with the corresponding possibility of the "system". In every possible state, the observer observes a single, definite outcome. The observer is just not "in" any one of those states but is in all of them at once (with a probability distribution of course). If you are the observer, you notice nothing different from your everyday experience: every observation appears to have a definite outcome despite what I have described. (The arguments behind this approach are complicated and I cannot do them justice here.) Note that this particular description of the "many worlds" approach is not commonly used but is equivalent to the more common descriptions.
This is certainly not the conventional interpretation of quantum mechanics among physicists. What you propose would be a hidden variable theory. It has been proven by some rather famous theoretical and experimental work that the only way a hidden variable theory can be compatible with the observed data is if it is non-local, i.e. it allows particles to interact instantaneously no matter how far apart they are. For various reasons this is not a popular idea with physicists. It doesn't agree well with Relativity, and tends to produce "inelegant" theories that don't work any better than conventional quantum mechanics.
The conventional interpretation is that when quantum mechanics predicts a probability distribution of possible results, it is not meaningful to talk about only one of those possibilities having occurred, in the absence of an observation. Opinions differ on whether an observation actually causes the system to "collapse" into one of the possible states, and what the exact definition of "observation" is.
NB: an "observation" does not necessarily have to involve a conscious mind.
Index Name: 1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl- (9CI)
Other Names: Caffeine (8CI); 1,3,7-Trimethyl-2,6-dioxopurine; 1,3,7-Trimethylxanthine; 3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione; 7-Methyltheophylline; Alert-Pep; Cafeina; Caffein; Cafipel; Guaranine; Koffein; Mateina; Methyltheobromine; No-Doz; Refresh'n; Stim; Thein; Theine; Tri-Aqua
Formula: C8 H10 N4 O2
Structure: Picture here
"I'm sorry, man. I'm just talkin' outta my ass."
The only cool property I can think of for a blue laser is that due to its higher frequency the beam can be focused more tightly, allowing more dense optical storage, etc. Someday soon we will use enhanced DVD's that are read by a blue laser diode.
Your children will spend a lot of time surfing the net, and will learn and retain just as much as you did (maybe more).
One also occasionally encounters 'guaranine' as an ingredient in trendy fruit juice cocktails. This is just another name for caffeine--named after the guarana berry which naturally contains caffeine.
Do you really have any concept how powerful a laser it takes to project a large raster-scanned image on a screen, that is bright enough to see in a lit room?
A few watts, properly focused, is easily enough to burn combustible materials (not to mention eyes).
Granted it may still be dangerous to the human eye, whether it's scanning or not, but so are laser pointers, and they're a bit easier to aim at someone's eyes.
Personally, I think most of the laser pointers on the market should be illegal. Most of them are class III lasers, easily able to damage a person's eye. Not something that should be in the hands of children, anyway.
Yeah, because THAT's not an unbelievable, overly elaborate way of trying to be malicious.
I'm not worried Al Queda is going to attack the Empire State Building with modified laser projectors strapped to sharks. I'm more worried about what a teenager with a soldering iron could do...
Are you a James Bond Supervillain or something?
No, just a laser physicist. But thanks for asking. Bwahahaha.
I don't actually expect laser projection displays to go anywhere. The advantage of a laser for projection is its high brightness (intensity in a small area). That's great for vector display where you want to "draw" bright lines. When you use a scanning laser for a raster display you lose this advantage, though. You need the same amount (intensity) of light with a laser as you would with ordinary projection. Unless the laser is more energy efficient than the ordinary projector, you're better off with the latter.
There are also safety/legal issues with laser projection. Any laser bright enough for a large projection display is dangerous if it stops scanning. The projectors of course have interlocks that shut off the laser if the raster scan jams or stops, but such a system could fail or be defeated by someone with malicious intent.
He should read up on what happened to Eric Weisstein's Mathworld website. In short Weisstein licensed a publisher to produce a printed "snapshot" of the website. After the book came out the publisher sued him and had his web site shut down for a year because it was infringing the book's copyright.
They understand the physics behind the overall rate of expansion of the universe, or at least they think they do. Knowing the current rate of expansion and its derivative is probably sufficient to predict the future outcome, assuming the theoretical model is correct. Of course, there are some questions about the basic model and it is not clear how they will be resolved in the end.
Did he buy any box cutters?
Interesting point. I wonder if it's legal to build a Faraday cage inside the walls of your theatre to block cell phone signals. You're not actually jamming anything, after all...
Are you sure they didn't just post a copy of the bill that fooled the cashier? Who would be dumb enough to stick an actual counterfeit that was good enough to fool a cashier up in a place where someone could just take it?
It also probably waited a while to be launched, and it took seven months just to get there.
Why alpha particles? Alpha radiation is really easy to block. I find it hard to believe that any would penetrate the shielding around the electronics, much less the electronics themselves.