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Fireworks on the Ground

  1. Jul 5, 2005 #1
    Has anyone ever set off a really big professional-grade star burst style firework on the ground, in a desert somewhere? Maybe at the Burning Man festival?

    I am thinking you could stand within 30 feet of the epicenter in a plexiglass enclosure, with ear protection, and be unharmed. What would an entire 20-minute fireworks show look like when experienced from almost ground 0?
     
  2. jcsd
  3. Jul 5, 2005 #2
    You might want to wear sunglasses too.
     
  4. Jul 5, 2005 #3
    Elwood: "It's 30 feet to ground 0, we've got a Plexiglass bubble and a pair of earplugs, it's dark, and we're wearing sunglasses." :cool:

    Jake: "Hit it."
     
    Last edited: Jul 5, 2005
  5. Jul 5, 2005 #4

    honestrosewater

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  6. Jul 5, 2005 #5

    cronxeh

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    Dear BicycleTree..

    what is the point of this idiotic experiment?
     
  7. Jul 5, 2005 #6

    honestrosewater

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    Yeah, I'm home with nothing to do. :rolleyes: There's much more to the article, BTW.
     
    Last edited: Jul 5, 2005
  8. Jul 5, 2005 #7
    To watch professional-grade fireworks go off all around you. It would be awesome.

    No, I'm just kidding. It would be done just to piss you off.


    If you're willing to sacrifice a little coolness, you could elevate the fireworks to a tower ten feet or so off the ground and have a whole field full of plexiglass viewing bubbles, two hundred people watching white phosphorous flares arching over them, streaking past them, and fissing down among them. In the fireworks that explode to hundreds of feet wide--the type that seemingly cover half of Plymouth Harbor--I wonder just how fast the sub-fireworks exit from the original explosion. That would probably determine the thickness of the Plexiglass.

    Regulations might be a problem, but you could probably get an exception made if it were clear you are making proper safety precautions for viewers.
     
  9. Jul 5, 2005 #8

    Moonbear

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    Heh heh, that's an understatement. Just try to get an insurer to provide a policy for that. I expect regulations of such displays require insurance before permits are issued.
     
  10. Jul 5, 2005 #9

    Danger

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    Forget acrylics—they'd melt. Maybe not all the way through, but enough to make them unusable in future and quite possibly enough to release toxic chemicals to the interior.
     
  11. Jul 5, 2005 #10
    Hmm--you could have the plexiglass sprayed with water or clear oil. Hopefully the trickles wouldn't interfere with the viewing. Maybe there is some solid heat-resistant transparent substance that you could coat the plexiglass with. Some reduction in transparency is OK--you can just wear lighter sunglasses to make up the difference. If you had a rounded bubble, the fireworks could never be in contact with the plexiglass very long.
     
  12. Jul 5, 2005 #11

    cronxeh

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    plexiglass viewing bubbles.. interesting

    consider this however: melting point of most plastics is from 310 degrees F (Noryl) to about 621 F (Teflon). Ah but those arent transparent! The ones you want are transparent plastics, and Acrylic has a continuous service temperature in presence of air of about 180 F max. Coefficient of linear expansion for Acrylic is 1.3 * 10^4. It ranks pretty good with other transparent plastics - at about 92% light transmittance - you may also consider Perspex (92% light transmittence, continuous service temp 180F); or better yet-

    Polycarbonate aka Lexan (91% light transmittence, continuous service temp 475F - will start deflecting at 539F, coeff of linear expansion 3.9 * 10^5 );

    PALSUN or PALTUF polycarbonate (89% light transmittence, continuous service temp 248 F)

    Now the firework components:

    Red strontium salts, lithium salts
    lithium carbonate, Li2CO3 = red
    strontium carbonate, SrCO3 = bright red

    Orange calcium salts
    calcium chloride, CaCl2
    calcium sulfate, CaSO4·xH2O, where x = 0,2,3,5

    Gold incandescence of iron (with carbon), charcoal, or lampblack

    Yellow - sodium compounds ( sodium nitrate, NaNO3; cryolite, Na3AlF6)

    Electric White - white-hot metal, such as magnesium or aluminum, barium oxide, BaO

    Green - barium compounds + chlorine producer, barium chloride, BaCl+ = bright green

    Blue - copper compounds + chlorine producer, copper acetoarsenite (Paris Green), Cu3As2O3Cu(C2H3O2)2 = blue
    copper (I) chloride, CuCl = turquoise blue

    Purple - mixture of strontium (red) and copper (blue) compounds

    Silver - burning aluminum, titanium, or magnesium powder or flakes

    How hot do those burn?

    Kelvin Celsius Color
    750 480 faint red glow
    850 580 dark red
    1000 730 bright red, slightly orange
    1200 930 bright orange
    1400 1100 pale yellowish orange
    1600 1300 yellowish white
    > 1700 > 1400 white (yellowish if seen from a distance)

    So from 750 Kelvin (red) to 1700 Kelvin (white) - thats about 890F to 2600F

    You see.. the sucky thing is.. 890F > 475F. That is where those coefficient of expansions come into play - you can even calculate a double integral of the time it would take for a flare to pass through an n inches thick transparent plastic bubble and cook them alive inside.
     
    Last edited: Jul 5, 2005
  13. Jul 5, 2005 #12
    Hmm... sounds like chicken wire in front of the plexiglass might be the only way to go. Unfortunately that would interfere with viewing. :frown:

    It's not as bad as it seems, though. Most of these things would be moving at probably something like a hundred miles an hour when they hit the plexiglass. They'd bounce right off with hardly enough time to get it warm.
     
    Last edited: Jul 5, 2005
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