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Physics, Astronomy & Cosmology / Re: Can a mass be lifted with force less than its weight ?
« on: Today at 12:44:38 »
The weight of an object is defined as the force required to lift it. So the question is absurd.
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Just Chat! / Re: Theories to start a new world.
« on: Today at 09:53:23 »You just don't ask questions like "is there a record player on the island and a small power station that provides a standard British mains electrical socket?"DID was first broadcast in 1942. The "given" was a wind-up gramophone and
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an infinite supply of gramophone needleswhich suggests that the originator, Roy Plomley, was a mathematician. A physicist would have insisted on a semi-infinite supply with an initial condition of n> 0 and a minimum amplitude of 1.
I'm not sure how religion satisfies loneliness, but I do see it providing purpose.No shortage of purpose here - we are going to export "civilisation", however we define it. Which raises an interesting question: if we are going to a habitable planet, it is reasonable to assume it already contains a balance of flora and fauna. To what extent are we entitled to alter that balance?
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New Theories / Re: Origin of magnetic force
« on: Today at 09:40:04 »
But it builds up again when you open the switch (1:30). And it is always the same sign, So there's something else going on here.
And the baffling question is why an alternating current should induce a unidirectional movement of static charge.
I'm not sure what you mean by this. Do you refer to the corrugated plastic plate?At 5:13 you lift the plastic plate, thus potentially redistributing charge between the cans (your body capacitance is very large compared with the cans). If you used two sheets of plastic the charge disturbance would be less.
Where do you want the plate to move to?
And the baffling question is why an alternating current should induce a unidirectional movement of static charge.
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Physiology & Medicine / Re: Can I utilise a telescope to enable me to see in the dark?
« on: Today at 09:30:44 »
Which is why you could use a prime lens of about f/0.3 to collect the light and squeeze it all through the pupil of your eye.
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Just Chat! / Re: Theories to start a new world.
« on: Yesterday at 23:17:36 »
Apart from the need for society, which would anyway be satisfied by being cooped up in a space ark with likeminded individuals, I seriously doubt whether the average dog or rat could make a living by persuading others to worry about ceasing to exist, or the origin of the universe. And even when groups of other species fight each other, it seems to be mostly about territory or food, not what they think the other guy's mother did on Sunday.
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Question of the Week / Re: QotW - 24.12.12 - Is there any way to harness nuclear energy other than steam?
« on: Yesterday at 22:52:47 »
My father worked for the UK Central Electricity Generating Board from 1945 (coal) to the late 60s when power reactors were diversifying from the original Magnox design. His comment on the entire program was "a very complicated way to boil water".
His favorite boiler actually used slurry pumped out of coal mines and coal washing facilities.
His favorite boiler actually used slurry pumped out of coal mines and coal washing facilities.
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Physiology & Medicine / Re: Can I utilise a telescope to enable me to see in the dark?
« on: Yesterday at 22:43:14 »
Light-gathering efficiency is roughly related to the ratio of pupil diameter to focal length. Conventionally we use photographic jargon: the f-ratio of a lens is f/d and the smaller the number, the bigger the entrance pupil. The human eye has a maximum pupil of about f/3.5. The largest practical lens is about f/0.3 which will give you a gain of about 30 but a very shallow depth of focus and quite likely all sorts of distortion.
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Just Chat! / Re: Theories to start a new world.
« on: Yesterday at 18:12:23 »
Virgin birth, water into wine, feeding 5000 people with half a loaf, walking on water....is "gospel truth" not an oxymoron?
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New Theories / Re: Origin of magnetic force
« on: Yesterday at 09:51:26 »
The ohmic interfaces may well be dictating the nature and quantity of the critical charge carriers, which is why I asked.
What is not clear is why the cans acquire a charge differential in the first instance.
As usual, I am hugely impressed by your experimental ingenuity and dexterity, but not by your critical review of the results.
1. Did you repeat all three scenarios? Were the differences statistically significant?
2. What happens if you use two sheets of dielectric and only move the top sheet?
3. What happens if you use two separate sheets of dielectric, one for each can?
Practical electrostatics is much more difficult and prone to all sorts of errors than electrodynamics!
What is not clear is why the cans acquire a charge differential in the first instance.
As usual, I am hugely impressed by your experimental ingenuity and dexterity, but not by your critical review of the results.
1. Did you repeat all three scenarios? Were the differences statistically significant?
2. What happens if you use two sheets of dielectric and only move the top sheet?
3. What happens if you use two separate sheets of dielectric, one for each can?
Practical electrostatics is much more difficult and prone to all sorts of errors than electrodynamics!
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Just Chat! / Re: Theories to start a new world.
« on: 08/12/2024 21:24:48 »That's a nice reply and can have the best answer award.Perhaps we need to have a "nicest answer" or "future diplomat" box, since however civilised and gentlemanly it was, it didn't actually address the question!
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New Theories / Re: Origin of magnetic force
« on: 08/12/2024 21:13:14 »
Just for once the chatbots seem to be right.
What thickness of Al foil were you using? Was it pure Al? The resistance measurement seems remarkably high.
What thickness of Al foil were you using? Was it pure Al? The resistance measurement seems remarkably high.
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Physiology & Medicine / Re: Can I utilise a telescope to enable me to see in the dark?
« on: 08/12/2024 21:09:12 »
Night vision goggles or monoculars use electronic image intensification to present a clear if somewhat noisy monochrome image from photon intensities well below the human threshold of detection. Features are recognisable under conditions known as "veiled starlight". The noise and granularity of the image is due to the fact that unlike a camera (or even the human eye) the intensifier responds to single photons: there is no integration period so movement is detected in real time.
In practice these devices are usually coupled with telescope optics for military and zoological purposes but the intensifier element works just as well with a wide-angle lens.
In practice these devices are usually coupled with telescope optics for military and zoological purposes but the intensifier element works just as well with a wide-angle lens.
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Just Chat! / Re: Theories to start a new world.
« on: 08/12/2024 10:29:19 »Insulting every religion is something I'm not sure we can do.There is no need for us to do so. Most of them insult all the others, and all of them claim to be at least better than all the others. Unlike detergents, there is no objective test of any of them, but current events in the Middle East and Myanmar demonstrate how they can destroy civilisations.
Last night I attempted to bring a taste of civilisation (live music) to a group seated in a place where they appear to worship a Roman instrument of torture - a huge illuminated crucifix. Strange things, people.
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New Theories / Re: Where does quantization of energy of electromagnetic radiation come from?
« on: 07/12/2024 16:25:03 »we see a smooth increase in frequency of the emitted radiationi.e the emitted spectrum is not generated by a quantum process, which would imply a discontinuous spectrum.
The photocell however will only react when a specific frequency is reached, indicating quantisation.So use a thermocouple detector instead.
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New Theories / Re: what is temperature?
« on: 07/12/2024 16:19:40 »
The result of vibration is thermal energy.
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Chemistry / Re: Shrink ray or growth ray, how could they work?
« on: 07/12/2024 16:16:50 »What we have a real opportunity to do, is to change the di-electric or practical ε in the environment around the atoms.We might substitute other atoms or dopants but this won't merely alter the bulk size of our target, but its chemistry and physics - in other words you will be making a completely different object.
Consider a protein molecule surrounded by water. If you substitute liquid hydrogen sulfide for the water you might indeed cause the protein molecule to shrink, but the mouse that works by the interaction of proteins with water will cease to do so. Or to take a simpler example, changing the dopant of a semiconductor will alter the effective density of the electron cloud of the parent material, but p- and n-doped substrates have very different functions.
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Question of the Week / Re: QotW - 24.12.12 - Is there any way to harness nuclear energy other than steam?
« on: 07/12/2024 10:14:15 »
The trick with a beta energy source is charge separation. Consider a metallic beta source surrounded by a conducting sphere with an air gap. Even at 500 keV, beta radiation is mostly absorbed in a few millimeters of copper, so you now have a self-charging capacitor C. V = Q/C, so the available voltage between the source and the absorber can be anything from zero to 500 kV depending on the ratio of beta activity to current drain.
This technique has the advantage over plutonium thermoelectric generators that it doesn't need a cold sink. PuTEGS work OK in space where you can radiate heat to the 3K background, or in the human body where you have 70 - 100 kg of water at a constant 310K, but if you want the simplest possible source of, say, 100 volts, with a wide range of operating ambient you might consider a beta capacitor.
This technique has the advantage over plutonium thermoelectric generators that it doesn't need a cold sink. PuTEGS work OK in space where you can radiate heat to the 3K background, or in the human body where you have 70 - 100 kg of water at a constant 310K, but if you want the simplest possible source of, say, 100 volts, with a wide range of operating ambient you might consider a beta capacitor.
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New Theories / Re: How close are we from building a virtual universe?
« on: 07/12/2024 09:55:52 »How do you define bad people?Those whose actions harm others.
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Chemistry / Re: Shrink ray or growth ray, how could they work?
« on: 07/12/2024 09:51:36 »
Problem is that you can't alter ε0 as it is a quantity derived from observation. You can immerse your subject in a dielectric d with a different value of εd but the volume occupied by the constituents of an atom is filled by vacuum 0, not d.
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New Theories / Re: Where does quantization of energy of electromagnetic radiation come from?
« on: 07/12/2024 09:42:39 »
The question here is "where does quantisation of the energy of emr come from". If you accept that it is possible to generate emr of any arbitrary frequency, then it is clear that the energy is not necessarily quantised and the answer is that in many but not all cases it is generated by a quantum process.