Cav
pfm Member
Please do not interrupt adults when they are talking...Tbf, you rarely do..
Please do not interrupt adults when they are talking...Tbf, you rarely do..
Well, I've got 1968 Oxford and Cambridge Joint Board A level physics, so obviously much harder than yours on all counts, and I don't remember any of that guff re permanent magnets. Is it true, I wonder?I can see how a conductor gets hot through the vibration, rather than the flow, of electrons. But I still don't see how the energy flow is through the surrounding fields, but only hurts people if they touch the conductor. That bit is weird.
Which brings me to a related topic which I think I've raised before, but for which I don't recall a satisfactory answer... To whit..
According to my 1965 Cambridge Board (The hardest obviously...) O Level Physics, plus my general layman's science knowledge.. 'permanent' magnets work by having all of their atoms/molecules aligned in such a way that they act, effectively as a 'lens' for the lines of force in the Earth's magnetic field, focusing them in much the same way that an optical lens focuses light waves. So... what happens when you remove a permanent magnet from the Earth's magnetic field? You take it out into deep space for e.g. Assuming you haven't taken it into a replacement magnetic field, does it still act as a magnet? Mmmm? Mmmmm?
Of course I could be talking bollox. It's that time of night and it has been known.. although very rarely...
Not currently.Yes but will he have any potential puns?
Well, I've got 1968 Oxford and Cambridge Joint Board A level physics, so obviously much harder than yours on all counts, and I don't remember any of that guff re permanent magnets. Is it true, I wonder?
Eitherway.. I'm looking to the intellectual PFM Gods of Physics for guidance in this matter.
The term "proved" has to be properly qualified:So experiment proved theory?
Well sort of. As @Mike Hanson writes, when testing a theory / hypothesis / conjecture (depending on how well an "educated guess" is known to work at predicting reality) mostly you are looking for a contradiction that disproves it - either generally or in a particular circumstance that establishes some limit on where it works.So experiment proved theory?
Those of us who noticed were nodding our heads at your clearly demonstrated comprehension.P.S. I'm a bit miffed that nobody seems to recognise Reluctance as a genuine electro/magnetic term. I'm a relative ignoramus and I've heard of it.. Try to keep up chaps!
The problem with theoretical physics is that experiment and proof are always lacking - if they were not, it would not be "theoretical".
I don't think any of my scientific predecessors were cretins. They didn't get it all right, but they built on what had gone before. Euclid came up with his model of geometry, OK it only works on a flat plane but it certainly works. The ancient Egyptians (I think) had Pi down as 3 from practical measurements. One ancient civilisation even had it at 4. Were they idiots? No, they were developing the model and building on it. In the same way *some* of modern science will be discredited but the vast majority of it is sound and will remain so. Ohms Law will remain true EVEN IF someone comes up with a special case where it doesn't. At that point nobody will throw away every electronics text and start again, they'll simply add an addendum that says (notwithstanding the Smith -Johnson anomaly of 2087). Even the much-quoted existence of wave particle duality does not discredit the science of how waves work and how particles do. Scientists learn from the past, question it and build upon it. They might have to remove bits of it that were a dead end, but they don't demolish the entire edifice and start again. In this they are like the cathedrals built in the Middle Ages, the stonemasons of the time didn't understand civil engineering and bits of their constructions don't quite work, but we don't tear them down. We recognise their limitations and build on them. The basics that still work, and the necessary modifications, such as the mini spires atop buttress attachment points that are needed to stop the wall being pushed off vertical, remain.Well it sounds like you have enlightened teachers. I think that studying the history of science should be compulsory for all scientists, as you go from thinking that our forebears were cretinous fools for believing that there are four elements (earth, air, fire, water), there's an aether, or that the world is flat etc etc, to realising you're on a continuum, and that future generations will have the same low opinion about us and our current theories and understanding. 'They used to believe that electricity travelled in what they called electromagnetic fields in the space around the wire, ha ha ha' etc
Atoms are almost entirely empty space so in theory we would expect to pass through solid walls and fall through floors but we don't. This behaviour can be explained using the Pauli Exclusion Principle and the uncertainty principle. This is an example of modern physics.
The universe is a strange place and I am beginning to think that everything that we observe in this physical Universe are all made from incredibly small vibrating waves.
DV
P.S. I'm a bit miffed that nobody seems to recognise Reluctance as a genuine electro/magnetic term. I'm a relative ignoramus and I've heard of it.. Try to keep up chaps!
I always thought that electrons "flowed" at varying depth around the skin of the conductor and not necessarily via the centre.
You may need to know something about how some types of cartridge work, or transformers to geddit.