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Chemistry / Is brass plating possible?
« on: 06/09/2013 20:15:24 »
Copper. Zinc, Silver, God, Chrome etc...elements.. Plating seems straightforward but brass is an alloy??
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Famous Scientists, Doctors and Inventors / Who invented television?
« on: 28/07/2010 03:00:22 »
The first ideas for scanning and sequential transmission of picture information for TV were from France but Alexander Bain (a Scot) invented the fax machine in 1846 which involved scanning and sequential transmission. Nipkow (German) had the brilliant idea of a simple disc scanner and patented a full TV system in 1884. Campbell Swinton (A Scot) proposed electronic TV in 1908. Baird (A Scot) developed TV based on Nipkow's
disc. EMI (UK) worked on electronic TV using Zworykin's (Russian working in the USA) camera tube.
disc. EMI (UK) worked on electronic TV using Zworykin's (Russian working in the USA) camera tube.
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Chemistry / Why does milk go off in a vacuum flask?
« on: 20/07/2010 22:00:55 »
It seems to go off quite quickly in a sealed container.
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Physics, Astronomy & Cosmology / What is the effect of solar activity on the ionosphere?
« on: 30/07/2009 22:42:56 »
.........Maxima why is there such a dramatic effect on the ionosphere?
It seems to become much more ionised. Solar radiation only increases by 0.1% . It might be a little higher in the UV region.
[MOD EDIT - PLEASE PHRASE YOUR POSTS' TITLES AS QUESTIONS, IN LINE WITH FORUM POLICY - THANK YOU - CS]
It seems to become much more ionised. Solar radiation only increases by 0.1% . It might be a little higher in the UV region.
[MOD EDIT - PLEASE PHRASE YOUR POSTS' TITLES AS QUESTIONS, IN LINE WITH FORUM POLICY - THANK YOU - CS]
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Technology / Is wireless power likely to become a reality, or remain a pipe-dream?
« on: 23/07/2009 22:57:20 »
This article seems to be full on inaccuracies and nonsense.
http://news.bbc.co.uk/1/hi/technology/8165928.stm
http://news.bbc.co.uk/1/hi/technology/8165928.stm
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Physics, Astronomy & Cosmology / What is the highest audio frequency which can be transmitted though air?
« on: 18/07/2009 19:39:50 »
It is possible to have acoustic waves to around 3 GHz in some media but maybe that is a restriction of the transducers and not the media?
Does air have a cut-off?
Does air have a cut-off?
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Physics, Astronomy & Cosmology / Why does the Moon look bigger when it is at a low angle?
« on: 17/07/2009 08:55:46 »
Why does the Moon look bigger when it is at a low angle?
I was on the M6 near Brum some weeks back at about midnight and the Moon looked enormous.
Is it the Ponzo illusion? There was a lot of large well lit buildings in view also.
I was on the M6 near Brum some weeks back at about midnight and the Moon looked enormous.
Is it the Ponzo illusion? There was a lot of large well lit buildings in view also.
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Physics, Astronomy & Cosmology / From what distance could you see the Sun with the naked eye?
« on: 17/01/2009 12:59:15 »How bright is it compared to the stars we can see from Earth?
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Technology / What is SIGSALY and how does it work?
« on: 07/11/2008 18:35:28 »
Anyone know how SIGSALY worked? I thought it was analogue - simple addition of noise and then subtraction at the receiving end but it looks as if it was 'digital'.
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Physics, Astronomy & Cosmology / What is the ionosphere and how does it affect radio communications?
« on: 07/11/2008 14:33:04 »
Does the D-layer never reflect signals? It absorbs MF (medium wave.. AM band) signals during the day when it is highly ionised. At night the ionisation disappears (no solar radiation) and signals are reflected by the E-layer. Seems strange that the D-layer has a large effect only up to around 2 MHz and as far as I know never reflects any signals.
Maybe some physicists out there can eplain the mysteries of the various layers. D E and F1 and F2. Is it to do with density at different heights? Are there A and B layers? Why does the level of ionisation effect different frequencies so differently?. Normally signals don't get reflected about 30 MHz but at periods of high sunspot numbers low-VHF can be received over short wave like distance.. BBC TV from London on 45 MHz (now shut down) for instance being receieved in South Africa or Australia. And at times FM band and higher frequencies refelect off the E-layer (unrelated to sunspot max),,Sporadic E. One theory was that the later was caused by thunder storms.
I am radio engneer but know little about the physics involved.
Maybe some physicists out there can eplain the mysteries of the various layers. D E and F1 and F2. Is it to do with density at different heights? Are there A and B layers? Why does the level of ionisation effect different frequencies so differently?. Normally signals don't get reflected about 30 MHz but at periods of high sunspot numbers low-VHF can be received over short wave like distance.. BBC TV from London on 45 MHz (now shut down) for instance being receieved in South Africa or Australia. And at times FM band and higher frequencies refelect off the E-layer (unrelated to sunspot max),,Sporadic E. One theory was that the later was caused by thunder storms.
I am radio engneer but know little about the physics involved.
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General Science / What is the probability of 5 presidents out of 43 being left handed?
« on: 25/10/2008 18:33:19 »
--------------------------------------------------------------------------------
4 out of 5 recent US Presidents have been left handers? Given that 1 in 10 of the population is left handed what is the probability of this? Say it was taking socks out of draw with the light off.. 1 White to 9 Black. What are chances of having 4 White and 1 Black.. I get 0.00045 ??
More accurately what is the probability that a continuous sequence of 5 presidents out of 43 has 4 left handers?
Mod edit - Formatted the subject as a question - please do this to help keep the forum tidy and easy to navigate - thanks!
4 out of 5 recent US Presidents have been left handers? Given that 1 in 10 of the population is left handed what is the probability of this? Say it was taking socks out of draw with the light off.. 1 White to 9 Black. What are chances of having 4 White and 1 Black.. I get 0.00045 ??
More accurately what is the probability that a continuous sequence of 5 presidents out of 43 has 4 left handers?
Mod edit - Formatted the subject as a question - please do this to help keep the forum tidy and easy to navigate - thanks!
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Technology / How can you cool things down in space?
« on: 31/08/2008 12:57:15 »
Trying to settle an argument. I reckon this a problem in satellites. Someone claims it isn't as space is cold??. No cooling air you see.
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Just Chat! / This morning we were informed that inflation in Zimbabwe was now 11.2 million %
« on: 20/08/2008 14:24:26 »
This morning we were informed that inflation in Zimbabwe was now 11.2 million % pa. This means,continued the correspondent, that something which costs £1 today will cost £10,000 next week.
Way out, surely.
Way out, surely.
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Technology / Do magnets on car fuel lines affect engine running and efficiency?
« on: 05/05/2008 18:04:53 »
You can buy magnets to attached to your car's fuel line. What is this supposed to achieve?
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Chemistry / Why is methane such a potent greenhoues gas?
« on: 03/03/2008 18:58:18 »
I asked elsewhere and nobody knows.
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Physics, Astronomy & Cosmology / How tall could you build a tower on the moon?
« on: 09/12/2007 18:10:08 »
Low gravity and no wind.
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Technology / Electric vehicles.
« on: 09/12/2007 18:00:07 »
Impractical with the technology we have today?
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Technology / The UK Gov think wind can supply all homes in the uk??
« on: 09/12/2007 17:58:29 »
I think the figures don't add up.
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