Science Trivia Questions

Discussion in 'Science' started by HereWeGoAgain, Jan 29, 2018.

  1. Derideo_Te

    Derideo_Te Well-Known Member

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    Baking soda?
     
  2. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    Not thunder but you're going the right direction.

    The lower limit for human hearing is about 20 Hz. Brain waves when awake range from 3.5 to 14 Hz and higher, but mostly under 20 Hz. And interestingly there is a transition from theta to alpha waves at 7.5 Hz.

    You might say that 7.5 Hz is the center frequency, which is really interesting.
     
    Last edited: Feb 13, 2018 at 5:25 AM
  3. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    F = dP/dt --> the rate of change of momentum is equal to the force applied. As soon as you let go, the momentum, hence the velocity begins to change. But mamooth got it - thermodynamic motion; the motion of atoms and molecules due to temperature. This can for a tiny fraction of second, counter the force of gravity by providing a net upward momentum.

    Not trains.

    And the rest you mentioned have been answered. :) There is a list at the top of the previous page.
     
    Last edited: Feb 13, 2018 at 5:33 AM
  4. truth and justice

    truth and justice Well-Known Member

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    Thunder is mostly in the 100 HZ range but can occur below 20hz . After a quick search, so cheating a little bit, came across a book (nearly 1000 pages long!) about the physics of cloud formation where it describes hailstone spin being in the range of 9 HZ which gives rise to the unique shape of hailstones though appears to be based on theory rather than measurement.
     
    Last edited: Feb 13, 2018 at 5:47 AM
  5. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    Haha, maybe to be fair I need to narrow it down a bit. It is an electromagnetic phenomenon. Just as are brainwaves.
     
  6. mamooth

    mamooth Well-Known Member Past Donor

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    Perhaps the stroke/return stroke cycle in a lightning strike?
     
  7. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    Not the lightning...

    I think those frequencies would be a little higher than those in question.
     
  8. Pycckia

    Pycckia Well-Known Member

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    I would say bicycles. They return much more of the potential energy gained going uphill than walking.

    How about roller skates? Or ice skates (but I don't know they can be considered a common form of transportation.)
     
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  9. Pycckia

    Pycckia Well-Known Member

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    Aerodynamic lift caused by the reduced air pressure caused by the hot coffee heating the air above it.
     
  10. Pycckia

    Pycckia Well-Known Member

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    According to this web site it requires .6 kcal to walk one mile at 2 miles/hr
    and .32 kcal to bike one mile at ten miles/hr.

    http://www.runningtools.com/energyusage.htm

    One gallon of gasoline is 32,000 kcals.

    If a car engine gets 50 m/gal, it takes 160 kcals/m,
    so bicycling is indeed about 600 times more efficient.
     
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  11. WillReadmore

    WillReadmore Well-Known Member

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    Cool!

    I'm not good with calories - it seems like there are some tricky elements there that I haven't bothered to figure out.

    I'm not doubting your result, though. Your answer is far better than was mine.
     
  12. Aleksander Ulyanov

    Aleksander Ulyanov Well-Known Member

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    Maybe, but the bicycle isn't Candy Apple Red and can't go 100mph while carrying 2 girls
     
  13. WillReadmore

    WillReadmore Well-Known Member

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    <major flashback to teen years>
     
  14. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    Bicycles it is! It is the most efficient form of transportation.
     
  15. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    Already answered: Thermodynamic motion but not for the same reason. Random biases in the motion of particles can result in an upward momentum for a fraction of a second.
     
    Last edited: Feb 13, 2018 at 5:58 PM
  16. Pycckia

    Pycckia Well-Known Member

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    And slightly more efficient than in line skates which is slightly more efficient than ice skating, it turns out.
     
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  17. HereWeGoAgain

    HereWeGoAgain Well-Known Member

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    Question 13: What is this phenomenon?

    [​IMG]
     
  18. Pycckia

    Pycckia Well-Known Member

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    Mushroom cloud.
     
  19. Pycckia

    Pycckia Well-Known Member

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    A professor once asked on a test

    "How can you determine the height of a building using a barometer."

    There are at least 8 different ways to do this. Which ones can you think of?
     
    Last edited: Feb 13, 2018 at 7:41 PM
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  20. politicalcenter

    politicalcenter Well-Known Member

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    The "green flash" seen sometimes at sunset over the ocean.
     
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