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Thread: Archimedes' death ray re-created

  1. #1
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    Archimedes' death ray re-created

    or, things only MIT students would do:

    Archimedes Death Ray: Idea Feasibility Testing

    Ancient Greek and Roman historians recorded that during the siege of Syracuse in 212 BC, Archimedes (a notably smart person) constructed a burning glass to set the Roman warships, anchored within bow and arrow range, afire. The story has been much debated and oft dismissed as myth.

    TV's MythBusters were not able to replicate the feat and “busted” the myth.

    Intrigued by the idea and an intuitive belief that it could work, MIT's 2.009ers decided to apply the early product development ‘sketch or soft modeling’ process to the problem.
    Everything I need to know I learned through Googling.

  2. #2
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    Our 2.009 conclusion?

    Feasibility estimate confirmed!

    Sketch models rock!!

    Crop circles: MIT’s most ambitious hack? I actually watched this on the Discovery Channel years ago. Those crazy kids.

  3. #3
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    That might cause Jaime and Adam (and the producers of) the Mythbusters into re-trying this experiment -- with alot more mirrors next time!

  4. #4
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    They're going to be retrying it, according to my inside sources. (My friend from the MythBusters board Misha, who's going to be part of the experiment. He's a rocket scientist.)

    My argument has always been historical documentation. As in, there isn't any. Now, with most historical figures of the time, this means precisely squat, given how fragmentary records from the time are, but everything else everyone claims Archimedes did was documented within his own lifetime; this isn't.
    _____________________________________________
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  5. #5
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    It would be a cool build anyway. I would want one built to modern tolerences.

    Just to play with of course...

  6. #6
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    When I see very uneducated people in third-world countries roasting meat and other foods with little more than some cardboard, twine, and scraps of aluminum foil, I can certainly believe that Archimedes could invent a "death-ray" that's got a smooth enough surface to focus light within bow-and-arrow range (couple hundred yards).

    They had both copper and tin, and tin is soft, maleable, capable of being beaten into very thin sheets, applied over a frame, and highly polished using nothing more than vegetable matter (such as grass).

    I really don't think I'd be the one in the link to be standing next to the ship, however!!! Nosiree, not after seeing what kids do to ants with just a tiny magnifying glass!

    The only problem with this entire scenario is that that the boats were floating on the water. If they were manned, there's little doubt buckets using for bailing would have been put to immediate use.

    Then again, any attempt to put out of the fire may very well have resulted in the blinding ray being refocused... As the guy said in the link, "that’s hot!"

    And blinding.

  7. #7
    On the BBC series 'What the Ancients Did for Us' they built a small 'death ray' and used it to set light to a model ship, it was about a metre in diameter and composed of lots of tiny metal mirrors that could be individualy adjusted to a focus.

    It was very impressive.
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  8. #8
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    Archimedes was a righteous dude, who definitely doesn't get his due among the great unwashed. As, I'm sure, you smarty-pantses all know he set forth the first rules of orthographic projection, which is something I use everyday (of course, we have computers to do most of the legwork these days).

    I've always thought us autobody designers should get his birthday off, sort of like a national holiday. The only problem is I don't have a clue when it is. With my luck it's probably Christmas or sumptin'.

  9. #9
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    Even if the ship wasn't ignited wouldn't the glare be enough to blind everyone on board? It's rather hard to attack a target you can't risk looking at.

  10. #10
    I read a scifi story about the crowd at a football match being given silver backed leaflets as they went into the match and then at the moment the ref made a bad decision they all focused their beams on him and he went puff.

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    Quote Originally Posted by Frog march
    I read a scifi story about the crowd at a football match being given silver backed leaflets as they went into the match and then at the moment the ref made a bad decision they all focused their beams on him and he went puff.
    IIRC it was called "A slight case of sunstroke" By Arthur C. Clarke.

  12. #12
    Quote Originally Posted by captain swoop
    On the BBC series 'What the Ancients Did for Us' they built a small 'death ray' and used it to set light to a model ship, it was about a metre in diameter and composed of lots of tiny metal mirrors that could be individualy adjusted to a focus.
    Oh Yeah !! I remember seeing that one that was pretty impressive actually. they also did something similar in " What the Romans did for us" i remember as a kid i used magnifying glass to burn paper focusinng sunlight, that works too.

  13. #13
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    Quote Originally Posted by Laminal Cockroach
    Oh Yeah !! I remember seeing that one that was pretty impressive actually. they also did something similar in " What the Romans did for us" i remember as a kid i used magnifying glass to burn paper focusinng sunlight, that works too.
    True, but Archimedes didn't have a lens.

    People over at MythBusters (the board, anyway) have done the math, which indicates that there's a whole list of reasons it wouldn't work very well (like focal point, the one I understand), but they will retest it just to explain all of that. (I can't do the math myself, so I couldn't explain it very well. And if anyone goes over there to look for information, search for an old thread instead of starting a new one. Please. There's dozens of 'em.)
    _____________________________________________
    Gillian

    "Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

    "You can't erase icing."

    "I can't believe it doesn't work! I found it on the internet, man!"

  14. #14
    You in this Picture is that reflector meant to be flat or concave? Well its seems to be flat on the picture but how are they getting to reflect without the reflector having some kind of a curve

  15. #15
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    Concave. It'll reflect when it's flat - it just won't converge into a tight enough spot to burn wood.

  16. #16
    ABC News: Tests of Fabled Archimedes Death Ray Fail

    Their attempts to set fire to an 80-year-old fishing boat using their own versions of the device, however, failed to either prove or dispel the myth of the solar death ray. [...] The MIT team's first attempt [...] failed to ignite a fire from 150 feet away. It produced smoldering on the boat's wooden surface but no open flame. A second attempt from about 75 feet away lit only a small fire that burned itself out. [...] "We're not saying it can't be done," [Mythbusters' Producer] Rees said. "We're just saying it's extremely impractical as a weapon of war."
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  17. #17
    Quote Originally Posted by Gillianren
    True, but Archimedes didn't have a lens.

    People over at MythBusters (the board, anyway) have done the math, which indicates that there's a whole list of reasons it wouldn't work very well (like focal point, the one I understand), but they will retest it just to explain all of that. (I can't do the math myself, so I couldn't explain it very well. And if anyone goes over there to look for information, search for an old thread instead of starting a new one. Please. There's dozens of 'em.)
    They had real trouble aiming...

  18. #18
    The problem even if you did get it to work it is not reliable. Also remember the boat that was supposedly zapped by the death ray was in bow range. So while they are setting it up or aiming the mirrors one would think they are getting shot at. If I remember correctly this is why the Mythbusters busted it because it was not practical, not because it could not work.

  19. #19
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    Quote Originally Posted by mickal555
    They had real trouble aiming...
    That's because they didn't know how... Somewhere in the back of my mind, I remember seeing some technique where aiming a reflection can be done easily with a hole through the reflector. (I wish I remember) But it did not rely on seeing your own unique reflection on the target.

    So, given enough men (sorry ladies, but I think that's historically correct) I would think it would be plausible.

    But, I would also agree that it may have been meant to blind, and the resulting accounts were blown out of proportion.

  20. #20
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    Quote Originally Posted by Frog march
    I read a scifi story about the crowd at a football match being given silver backed leaflets as they went into the match and then at the moment the ref made a bad decision they all focused their beams on him and he went puff.
    Sort of begs the question as to why all football games aren't indoors under diffuse lighting, huh?

  21. #21
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    Quote Originally Posted by NEOWatcher
    That's because they didn't know how... Somewhere in the back of my mind, I remember seeing some technique where aiming a reflection can be done easily with a hole through the reflector. (I wish I remember) But it did not rely on seeing your own unique reflection on the target.

    So, given enough men (sorry ladies, but I think that's historically correct) I would think it would be plausible.

    But, I would also agree that it may have been meant to blind, and the resulting accounts were blown out of proportion.
    First, you're absolutely right about the men thing. Doesn't bother me to use the proper term.

    And, yes, you can use a hole through the reflector, but consider this: say you've got a hundred guys all trying to aim--how do they know which spot is theirs?

    And, finally, I do agree that it's possible that he made it to blind people. Since it wasn't recorded at all for so long, there was time for the story to grow. This is a point I've made several times. (Not here.)
    _____________________________________________
    Gillian

    "Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

    "You can't erase icing."

    "I can't believe it doesn't work! I found it on the internet, man!"

  22. #22
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    Quote Originally Posted by Gillianren
    Snip...And, yes, you can use a hole through the reflector, but consider this: say you've got a hundred guys all trying to aim--how do they know which spot is theirs?
    I did a little searching since my post, unfortunately, I can't find a nice concise description, but it looks like something every boy scout has learned at one point with signalling mirrors.

    Basically, you have an intermediate aiming point that you target. In the examples that I've seen, you hold your arm out, and aim the reflection at your fingertip. As long as you look from within the mirror (through the hole, and your fingertip is in line of sight to the target, then the entire reflection will continue on to the target.

    I'm sure they could have figured this out with something a little larger than a signalling mirror.

  23. #23
    Quote Originally Posted by NEOWatcher
    Basically, you have an intermediate aiming point that you target. In the examples that I've seen, you hold your arm out, and aim the reflection at your fingertip. As long as you look from within the mirror (through the hole, and your fingertip is in line of sight to the target, then the entire reflection will continue on to the target.
    Not quite. See this. It's short. I'll reproduce it:

    Simple Boy Scout heliograph description.

    Simply: Two silvered mirrors glued back-to-back with a small silvering-removed hole in the middle. Eyeball target through hole and align reflection of bright spot on cheek with target.
    That should eliminate the aiming problem of: which bright reflection am I controlling?
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  24. #24
    I used to play around with mirrors, reflecting the sun onto the house, when I was a kid. I'm sure, like with anything, you could develop the skill for pointing the reflection where ever you wanted to.
    You can start off the beam pointed at your feet and then move it off in the direction of the target.

  25. #25
    Quote Originally Posted by Frog march
    I used to play around with mirrors, reflecting the sun onto the house, when I was a kid. I'm sure, like with anything, you could develop the skill for pointing the reflection where ever you wanted to.
    You can start off the beam pointed at your feet and then move it off in the direction of the target.
    But, that is the problem of: when you have 50 people controlling mirrors, which of the 50 bright spots is the one I am controlling?
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  26. #26
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    I'm pretty sure I could burn paper with a 10 inch telescope mirror. The trick would be getting a mirror with a long focal length and then getting the target to hold still at just the right distance.

    maybe a large telescope mirror with a focal length of a hundred feet, mounted on a cart so the range to target could be adjusted?

  27. #27
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    I have an idea, I don't know if it is possible. You have the mirror attached to an aiming device. This aiming device has two parts, mechanicaly linked, but not directly, it uses gears and whatnot so each part doesn't move the same as the other parts. On end has a crosshair on it, and a person manipulates this to point at the target. The other part has a filtered scope that a person looks through and keeps pointed at the sun, so that as the scope tracks the sun across the sky, the mirror moves the correct amount to keep the reflection hitting where the crosshair is pointed. While the scope is being held on the sun, the crosshair end can be moved to aim, which causes the mirror to move in order to keep the reflection pointed at the new target under the crosshairs.

  28. #28
    Quote Originally Posted by 01101001
    But, that is the problem of: when you have 50 people controlling mirrors, which of the 50 bright spots is the one I am controlling?
    well maybe it would work if you had 1000 people doing it.

  29. #29
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    Quote Originally Posted by 01101001
    Not quite. See this. It's short. I'll reproduce it:
    That should eliminate the aiming problem of: which bright reflection am I controlling?
    Could be, since I can't remember... but either way could be a solution.

    Or for the totally absurd - everyone has a slightly different colored reflection...

  30. #30
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    People, I can't believe you're arguing about this. Even if the mirrors were little more than partially-polished copper sheets stretched/hammered against a wooden paddle, given a couple thousand of the local citizens standing along the shoreline and directed towards a pre-selected spot on the ship, the job would have been done!

    This isn't rocket science, folks.

    It's simple physics.

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