Science
1 lurker |
36 watchers
Nov 2023
12:51pm, 15 Nov 2023
48,440 posts
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HappyG(rrr)
Television: How images can be captured and transmitted (either analogue or digital) and then rearranged as images on a screen. Vinyl: How can a groove in a vinyl disk capture sound which can then be reproduced with suc richness and fidelity using a needle bouncing along that groove (I don't really understand anything) Computer - what Fetch said. (Though that doesn't make any of these things any the less wonderful and impressive). Sound - analogue is easier to explain than digital. Sound is a wave, right. As in peaks and troughs in air pressure, which reach your ear and your ear drum detects and calls sound. The needle in the groove literally goes up and down in an analogue of the sound wave in the air. This is amplified electrically and output to a speaker, which is just a cone that punches the air in and out, in the same pattern that is etched in the groove. Digital is just taking the peaks and troughs in the wave and representing them as numbers e.g. -50 to +50, which is then encoded as 1s and 0s that digital systems need. TV. Same, but harder, cos light has to be split into Red, Green and Blue, detected in intensity and recorded (old days, tape, as an amplitude, same as description of sound above), now digitally as a a "value" representing the intensity. All the reproduced by outputting varying intensity of light at Red, Green and Blue dots on a screen. Used to be a moving beam of electrons fired at materials that fluoresces (phosphor?) and filtered as RGB, to combine in right combinations to give the original colour. Digital, same, but all values encoded into numbers, as 1s and 0s. Did people actually want dumb attempts at explaining stuff? Apols if not!  G
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Nov 2023
12:53pm, 15 Nov 2023
48,441 posts
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HappyG(rrr)
Meant to say, now LEDs turned on and off directly, no need for a gun of electrons (hence why it's not a big fat tube anymore!). G |
Nov 2023
1:00pm, 15 Nov 2023
19,934 posts
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Cerrertonia
Dio - my job is (kinda) doing design of CPUs. Back in the 1990s, we drew circuit diagrams to construct adders and things out of transistors and a really complicated design might involve tens of people to do and tens of thousands of transistors. Nowadays we have big libraries of pre-designed blocks, and software does a lot of the work and we can do designs with tens of billions of transistors. It's exactly like Fetch said - you just scale up until you take over the world.
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Nov 2023
1:23pm, 15 Nov 2023
993 posts
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Silent Runner
not the sealed air thing, it's conservation of momentum. When you jump or float up, you already had the same forward momentum as the plane, therefore you keep going forward at same speed as the plane. Newton's first law. G The sealed air bit is necessary too - if the plane was open at both ends, it'd be a very different experience for the passengers... In terms of forces, it's very definitely relevant whether the plane is sealed or not! In a vacuum it would make no difference, because, as you said, your forward momentum is conserved. Gravity is the only force acting and its direction of action is vertical, so it has no effect on your forwards/backwards motion. (I don't recommend trying to fly a plane in a vacuum, though ) If the plane is open to the air then you introduce a new force, air resistance (friction) and it's this that would cause you to be dragged out of / slammed against the back of the plane. |
Nov 2023
1:24pm, 15 Nov 2023
24,312 posts
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richmac
Television: How images can be captured and transmitted (either analogue or digital) and then rearranged as images on a screen. Vinyl: How can a groove in a vinyl disk capture sound which can then be reproduced with suc richness and fidelity using a needle bouncing along that groove (I don't really understand anything) The vinyl bit is the easy one, the needle is connected to what I'd call a potentiometer depending on how far up or down it is dictates what voltage goes through the equipment & produces sound. TV. After it's left Happy G's description & arrives the business end by wire it's magic but basically the signal of ones and noughts goes into a transmitter which translates it into RF by generating a magnetic field containing all the relevant information, this goes in a thing (or it did ) called a klystron amplifier, then into a thing that looks like an oil drum to combine it with any other signals you want to transmit, then down a vacum pipe called a feeder, up the tower/mast to where it's split into however many feeds that the tower has antenna's (usually 2) into the antenna where the RF is transmitted. Basically, magic. |
Nov 2023
1:24pm, 15 Nov 2023
82,633 posts
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Diogenes
Quite happy for the explanations, G, but the point I was clumsily trying to make is that I still find these simple things hard to comprehend, especially how people work them out in the first place. Thanks Cerrers, that's very interesting. As Ian Dury said, there ain't 'alf been some clever bastards. |
Nov 2023
1:26pm, 15 Nov 2023
2,485 posts
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MudMeanderer
It's not the sealed air thing, it's conservation of momentum. When you jump or float up, you already had the same forward momentum as the plane, therefore you keep going forward at same speed as the plane. Newton's first law. G The sealed air bit is necessary too - if the plane was open at both ends, it'd be a very different experience for the passengers... Not in terms of forces and being slammed against the back of the plane, which was the original question. In terms of breathing, of course, I completely agree! G That can slightly depend on the form of the aircraft you're in. If you're in something like a commercial airliner, and the contained air is largely moving at the same speed as the aircraft, even if it was open you'd probably not slow down quickly due to drag. However if you're in a light aircraft and essentially jumping into almost static air, the drag may slow you quickly. They apparently used to advise crew bailing from downed aircraft to dive at the trailing edge of the wing, as if they aimed behind it they could slow so quickly they'd hit the tail! |
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Nov 2023
1:29pm, 15 Nov 2023
48,442 posts
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HappyG(rrr)
not the sealed air thing, it's conservation of momentum. When you jump or float up, you already had the same forward momentum as the plane, therefore you keep going forward at same speed as the plane. Newton's first law. G The sealed air bit is necessary too - if the plane was open at both ends, it'd be a very different experience for the passengers... Not in terms of forces and being slammed against the back of the plane, which was the original question. In terms of breathing, of course, I completely agree! In terms of forces, it's very definitely relevant whether the plane is sealed or not! In a vacuum it would make no difference, because, as you said, your forward momentum is conserved. Gravity is the only force acting and its direction of action is vertical, so it has no effect on your forwards/backwards motion. (I don't recommend trying to fly a plane in a vacuum, though ) If the plane is open to the air then you introduce a new force, air resistance (friction) and it's this that would cause you to be dragged out of / slammed against the back of the plane. Absolutely, I was thinking of a vacuum. As both a vacuum and an unsealed plane at 8,000m both were somewhat moot! Agree, then, if open ends happened to be in the direction of travel (not sure how we got to this hypothetical example!) then there would be air resistance to take into account, which would retard your movement, relative to the plane. G
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Nov 2023
1:30pm, 15 Nov 2023
19,936 posts
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Cerrertonia
As Ian Dury said, there ain't 'alf been some clever bastards. Sixty years of lots of smart people around the world developing the ability to make silicon chips with hundreds of billions of components on, eighty years of lots of smart people working out how to design increasingly complex computers, eighty years of lots of smart people writing software, and all of it builds on top of what went before. |
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Nov 2023
1:33pm, 15 Nov 2023
48,443 posts
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HappyG(rrr)
Has everyone seen that (c) credit XKCD, used for illustration purposes only xkcd.com diagram about "dependency" on others in computer code?! Love it. G
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