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Science questions not worth a thread I: I'm a moron!

Discussion in 'Science & Technology' started by The Imp, May 4, 2010.

  1. gay_Aleks

    gay_Aleks communism will win.

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    Say, will wireless electricity ever be able to replace the current way we're transporting electricity (i.e, lots and lots of cables)?
     
  2. SS-18 ICBM

    SS-18 ICBM Oscillator

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    A robot activated by tactile feedback. Next.
     
  3. Tarquelne

    Tarquelne Follower of Tytalus

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    I came across a forum with a bunch of Venusian the other day. In an odd coincidence, they were discussing why helicopters won't work on Earth.

    NASA - Helicopters on Mars
     
  4. timtofly

    timtofly One Day

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    So if the motor stops the blades keep turning, but without enough push back the helicopter will start to spin also?
     
  5. uppi

    uppi Deity

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    No. There will be some special applications for wireless power, especially at very shot range. But for most of the electricity transport cables are much superior than what could ever be achieved by wireless power.
     
  6. brennan

    brennan Argumentative Brit

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    Not unless we can develop almost perfectly efficient ways of turning electrical energy into something else and back again, which seems unlikely.

    Using long distance AC infrastructure we don't even move the electrons themselves, just provide an extended electric field. It's incredibly efficient.
     
  7. El_Machinae

    El_Machinae Colour vision since 2018 Retired Moderator

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    Wireless is really inefficient, because remember that it transmits as a sphere, or even if it's focused, it loses 'density' at the square of the distance traveled. It would then transmit as a cone. So, unless your receiver was giant, you lose a great portion of the energy put into the transmission.

    I mean, we can think of some applications, but wires are just too awesome. You get some much distance out of them!
     
  8. Loppan Torkel

    Loppan Torkel Deity

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    There's also smaller drag. It could spin a lot faster given same energy and the rotors could be made of lightweight, folded material, like sails. ..and there's less gravitational force on Mars...

    http://www.esa.int/Our_Activities/Technology/Dropship_offers_safe_landings_for_Mars_rovers
     
  9. Loppan Torkel

    Loppan Torkel Deity

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    So, it's clear cut? No choppers on Mars, or is this a case of assuming it because it's presumed?
     
  10. Cutlass

    Cutlass The Man Who Wasn't There.

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    There would have to be some other form of aerial transportation. Helicopters just aren't that efficient aerodynamically.
     
  11. Kyriakos

    Kyriakos Alien spiral maker

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    Is that why wires are cylindrical? (due to the afforementioned tendancy of electrical currents to expand spherically?). Cause - as is known for around 2400 years now - Sphere+Cone=Cylinder, all of the same diameter.
    Other way to form the question: why weren't wires built as right-angled parallelepipeda, etc (basically, instead of an extending sphere forming a cylinder, you would have an extending cube) :)
     
  12. Michkov

    Michkov Emperor

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    I'd guess it has more to do with the way wires are produced rather than any advantage in geometry.
     
  13. uppi

    uppi Deity

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    One probably could make the argument that surfaces are always messy, so the conductivity in the bulk might be higher than near the surface. That would mean that the surface compared to the cross section should be minimized, so you want a cylinder.

    But I don't think the effect is big enough to notice for any wire of practically relevant size. Ease of fabrication is indeed the most important property of cylindrical wires.
     
  14. Cutlass

    Cutlass The Man Who Wasn't There.

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    I'm taking a lot of water to work to drink these days. Personally I think buying pre bottled water is an utter waste. So I bring a jug of it from home. But I got curious; how does the purity of my water stand up? I have a dehumidifier in the basement, and the water I'm using is condensed from the air. I expect there's a bit of dust in it, because the air in the basement is somewhat dusty. But overall how pure could I expect it to be?
     
  15. timtofly

    timtofly One Day

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    The point of distilling water is keeping it in a sealed container to keep it free from dust and bacteria that could be airborne. Most bottled water is not distilled, unless it states that it is distilled. Using a dehumidifier is a way to bring out water from the moisture in the air, how it is collected would be the issue. If it is allowed to be re-contaminated or not protected from bacteria growth which may be found in such conditions it would not be any different from tap water. A dehumidifier is not normally designed to produce drinking water due to the possible risks of microorganisms, airborne contaminants, and heavy metals such as copper and aluminum from the dehumidifier itself. If you had a way to boil that water and distill it, it would not be wasted, but then you could just run tap water through a filter as well. Even using the same container over and over without giving it the proper cleaning will eventually breed harmful bacteria.

    Wire is fabricated by "drawing" it through an opening. A drilled opening would have been the default method. I think it may have been possible to make a triangular opening or even an opening with more than 3 sides or surfaces. The default drilling method would be cylindrical. I wonder if any one has ever tested the efficiency of wire that is anything other than cylindrical?
     
  16. gay_Aleks

    gay_Aleks communism will win.

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    What about wireless electricity that is only limited to a certain area?

    For an example, the PC gets power from cable, but the peripherals would get power from wireless?
     
  17. El_Machinae

    El_Machinae Colour vision since 2018 Retired Moderator

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    'Optical fibre' made out of thin air

     
  18. Loppan Torkel

    Loppan Torkel Deity

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    Drinking too much distilled water isn't good for you in the long term since it seeps minerals out of your body (or so I've heard). I have no idea how potent this is or how pure your water gets, but just fyi..

    edit: nvm, it seems fine to drink it... :p
     
  19. dusters

    dusters Emperor

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    How to explain string theory to 10 year old girl in less than 100 sentences?
     
  20. madviking

    madviking north american scum

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