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19-Year-Old Makes Homemade Solar Death Ray 317

Posted by samzenpus
from the archimedes-approved dept.
An anonymous reader writes "Concentrated solar power has the potential to generate immense amounts of energy — but it can also be amazingly destructive. American student Eric Jacqmain has assembled over 5,800 mirrors into his own parabolic 'solar Death Ray'."

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19-Year-Old Makes Homemade Solar Death Ray

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  • Mythbuster 3.0 (Score:3, Informative)

    by martijnd (148684) on Thursday February 03, 2011 @06:40AM (#35088622)

    Looks like the mythbusters can redo this myth one more time.

    • by captainpanic (1173915) on Thursday February 03, 2011 @07:52AM (#35088882)

      The whole point of the death ray is to be able to adjust the focus point.
      The Mythbusters tried to set a boat on fire... which was assumed to be an enemy boat passing along the coast.
      You can't reasonably expect the enemy boats to sail exactly at the focus point of your death ray... or to either come closer or go further away in case they are not at the focus point of your death ray.

      This 19-year-old hasn't made the focus point adjustable... so you can't set a moving target at a variable distance on fire with it.
      Any dish shaped thing with mirrors has a focus point - especially satellite dishes - so this isn't exactly rocket science.

    • by elrous0 (869638) *

      Every time someone (like the kids at MIT) thinks they've "proven" this myth, Jamie and Adam invite them on and they inevitably fail under real-world conditions (especially when they're forced to use ancient materials like polished copper).

      I don't know why people are so determined to believe this obvious myth/exaggeration as fact. Just because some ancient genius did amazing things doesn't mean that EVERY story about them is true.

      • I will believe the myths about Archimedes over the attempts of Jamie and Adam any day. They definitely are smart, but they are no Archimedes. This is a man who died as the result of refusing to leave the city as it was sacked by Romans because he was busy working on an equation. As such, any rumors of his greatness that we cannot currently prove, I will simply call it lost technology. There are so many things about ancient civilizations in human history that we know they did, but still can't figure out how
  • Stay in School (Score:4, Insightful)

    by jevring (618916) on Thursday February 03, 2011 @06:41AM (#35088626) Homepage
    This is what a science education lets you do. Stay in school kids!
    • I wonder if his parents would rather he were a little less resourceful if it would get them back the shed his 'invention' burned down according to TFA.
      • by jevring (618916)
        That shed is simply the cost of doing business. You can't make an omelet without breaking a few eggs (or sheds, as it were). =)
  • The 19-year old claims that his solar device has the intensity of 5,000 suns.

    Yeah right! Sure!

    • Yeah right! Sure!

      Yes indeed it has, so what is your problem with it? Go read TFA and go watch the movie ... sigh

      • My understanding is that you can't use reflection of the sun to heat up a point on earth any higher than the temperature of the sun, because then you get a reversal of energy transfer... effectively the hot point on earth starts emanating energy that is reflected back towards the sun.
    • by Fleetie (603229)
      The concentrated spot of light cannot even be quite 1 x the brightness of the sun. Never mind ">5000 times brighter". The laws of thermodynamics say so. You cannot focus an image of a light source so as to make the intensity at that focus more intense than the light source itself. Kudos for good execution of his idea, but that ">5000 times brighter" claim is just plain wrong.
    • The 19-year old claims that his solar device has the intensity of 5,000 suns.

      Yeah right! Sure!

      Doesn't he know no one will care until it's over 9000 ?

  • by MichaelSmith (789609) on Thursday February 03, 2011 @06:50AM (#35088656) Homepage Journal

    You could get a nasty case of sunstroke [blogspot.com] from that thing.

  • by thewils (463314) on Thursday February 03, 2011 @06:51AM (#35088660) Journal

    I mean the focus is close enough that he could kill anything anyway by smacking it over the head with the reflector. Be nice if the focus was a bit further away.

  • Solar power does not "generate" energy. Energy is liberated by conversion from mass through nuclear reactions in the Sun. Solar power collects and transforms radiant energy into heat and then into useful work, like burning something up.

    Well I did warn you, you didn't have to read it!

    • My thought exactly. This merely focuses sunlight. It doesn't generate any energy, or even convert it for that matter.
  • by intellitech (1912116) * on Thursday February 03, 2011 @06:56AM (#35088678)

    Like ~2,000 years ago [wikipedia.org]. Talk about an old story.

    • by dkleinsc (563838)

      Not quite. It's more like his enemies at that siege said he'd done that, and no one's been able to replicate it since, unlike almost every other crazy machine Archimedes figured out.

  • "The 19-year old claims that his solar device has the intensity of 5,000 suns."

    Surely it has the intensity of 5,800 x the amount of solar energy collected by a tiny mirror 93m miles away from the sun?

    Also lol @ it being destroyed in a shed fire -- I wonder how that came about? :-)

    • by c0lo (1497653)

      "The 19-year old claims that his solar device has the intensity of 5,000 suns."

      Surely it has the intensity of 5,800 x the amount of solar energy collected by a tiny mirror 93m miles away from the sun?

      It is the intensity [wikipedia.org] (in W/sqm) not the energy or power. Given that he uses 5800 small mirrors concentrating the radiation on 1 sq.cm... here you go.

  • 5800 mirrors, the size of fingernails. Glued on an already parabolic disc.

    Couldn't he just have spray canned it with some reflective paint??

    I imagined at least 10x10cm mirrors. Now that would have been "solar power".

    wake me up when he heating his house with this. This little satellite disc is kids stuff.

    • by mangu (126918) on Thursday February 03, 2011 @07:16AM (#35088756)

      5800 mirrors, the size of fingernails. Glued on an already parabolic disc.

      He used an old satellite dish.

      Couldn't he just have spray canned it with some reflective paint??

      Or glued aluminum foil over it. Or chrome plated it. He chose the most cumbersome way. Everyone who works cutting glass gets some nicked fingers from time to time, imagine cutting 5800 tiny pieces.

      I imagined at least 10x10cm mirrors. Now that would have been "solar power".

      True, if there had been 5800 10x10cm mirrors. For the same surface size, the smallest the mirrors are the better focus he will get. Ideally, the surface should have an infinite number of infinitely small mirrors, i.e. it would be a smooth parabolic surface.

      • by jovius (974690) on Thursday February 03, 2011 @07:34AM (#35088822)
        The tiny mirror pieces are from a mirror ball. Yes, I actually do go out sometimes.
        • Re: (Score:2, Funny)

          by Anonymous Coward

          The tiny mirror pieces are from a mirror ball. Yes, I actually do go out sometimes.

          apparently not since the seventies :D

      • by DrXym (126579)

        Or glued aluminum foil over it. Or chrome plated it. He chose the most cumbersome way. Everyone who works cutting glass gets some nicked fingers from time to time, imagine cutting 5800 tiny pieces.

        I have no idea how the guy stuck mirrors to the parabola, but I'd point out that you can buy mirrored mosaic tiles either loose or stuck to a net backing. So you might buy a 20x20cm square which has 15x15 tiles on it.

        So it's not necessarily that hard work - draw a cross in centre of parabola, apply glue to one quadrant, apply tile swathe over glue, tamp down, repeat for other quadrants, work outwards, wait to dry, death ray.

      • by asylumx (881307)
        You can buy those mirrors fairly cheap at a crafts store (Michael's, Hobby Lobby, etc)
    • Dude, 5800 mirrors is nothing. I hold in my hand a solar death ray device that has probably billions of nanomirrors on it, each carefully aimed to focus light at a point.
    • Couldn't he just have spray canned it with some reflective paint??

      In middle school back in the 70's my brother covered the underside of an umbrella with aluminium foil, turned it over, mounted a grate on the handle/shaft near the focus, and grilled hot dogs using sunlight. It can be made much quicker.

    • The light sharpener [cockeyed.com] is the much more serious version done on an old school 12 foot satellite dish that is actually closer to deserving mention on slashdot. The article is annoyingly laid out over more than 20 pages, but it is kind of cool what he was able to do with that much concentrated solar power. He also didn't try any better methods of depositing a mirror on the dish. He did small tests with tinfoil and they showed the tinfoil was clearly less reflective than the mirror. Of course the problem with the
  • by Capt James McCarthy (860294) on Thursday February 03, 2011 @07:18AM (#35088766) Journal

    He said it was destroyed in a shed fire. He must have left it near a window in the shed. Now that's funny.

  • In the Himalayas... (Score:5, Interesting)

    by slim (1652) <john@ha[ ]up.net ['rtn' in gap]> on Thursday February 03, 2011 @08:07AM (#35088944) Homepage

    In the Himalayas, parabolic mirrors around this size are commonly used to boil kettles of water for tea/cooking.

    It works at those altitudes, because the sunlight is more intense (less having been absorbed by the atmosphere), and because water boils at a lower temperature at the lower atmospheric pressure.

    http://en.wikipedia.org/wiki/Solar_cooker#Solar_kettles [wikipedia.org]

    • There's a whole DIY field of solar cooker [wikipedia.org] makers. With a simple box and a few feet of foil lined cardboard panels it's easy enough to do a slow roast meal, in a Michigan winter sunny day. For just a few bucks of material it's a fun build.
    • In the Himalayas, parabolic mirrors around this size are commonly used to boil kettles of water for tea/cooking.

      It works at those altitudes, because the sunlight is more intense (less having been absorbed by the atmosphere), and because water boils at a lower temperature at the lower atmospheric pressure.

      http://en.wikipedia.org/wiki/Solar_cooker#Solar_kettles [wikipedia.org]

      Screw the Himalayas. I was 12 when our year 7 (1st year of junior high for you Americans) science class constructed solar ovens out of aluminium foil, a large tin can, coat hangar wire and masking tape. They were good enough to cook sausages and eggs and this was at sea level. It wasn't lame but it wasn't exactly difficult for a 12 year old. A smart but not genius 8 year old could do it.

      The parabolic reflector is only one design. Just Google solar oven science project for kids

      http://www.crystal-clear-scienc [crystal-cl...ojects.com]

      • Screw the Himalayas. I was 12 when our year 7 (1st year of junior high for you Americans) science class constructed solar ovens out of aluminium foil, a large tin can, coat hangar wire and masking tape. They were good enough to cook sausages and eggs and this was at sea level. It wasn't lame but it wasn't exactly difficult for a 12 year old. A smart but not genius 8 year old could do it.

        I built a solar hotdog cooker when I was 8, from cardboard and aluminum foil. My parents thought it was a great idea. Today, I have to worry about how badly Children's Protective Services will over react.

    • I recall reading that the Spanish plundered gold and silver discs that were several feet in diameter in their conquest of the South American peoples. It was suggested that they were solar concentrators similar to the one demonstrated, since smaller ones are known to have been used in lighting ritual fires, the larger ones may have had a more practical purpose, including shaping stone.
  • Would it be possible to pass the focussed light through a lens to make a concentrated ray? Or would the lens melt?

    • Given the parabolic dish, it should already be pretty well concentrated at the focal point. If you wanted to move the focal point a bit, for whatever reason, you could place an appropriately sized lens a bit before the focal point, to either move it out a bit, or move it a bit closer.

      Whether or not it would melt would depend on how efficient the lens is. An ideal lens(100% transmission, no absorption, internal reflection, or other funny stuff) wouldn't even notice. A real lens, with less than 100% transm
  • by Wdi (142463) on Thursday February 03, 2011 @08:20AM (#35089002)

    These mirrors are pretty thick, and when glued on the surface of the dish, he actually ended up with the mirror surface being out of alignment, so the focus point is far more smeared than that of the original, precisely designed and aligned dish.

    The proper thing to do would have been to chemically deposit a very thin silver layer on the dish surface. This is actually not difficult to achieve. The mentioned spray paint or aluminum foil solutions are also better than his really, really crude approach.

    • by lwsimon (724555)

      No doubt. I built something like this from an old 8' satellite dish as a science fair project once. I used aluminum foil, and put a black steel tank of water in the middle. Pump water in, water turns to steam, which I used to power a Greek steam turbine (aeolipile) to prove the point.

      I was in fifth grade.

  • He bedazzled a satellite dish, mounted it on a wagon with a 2x4 a painted it silver? This made it on Slashdot?
  • As long as they hold very still at exactly two feet away from me. Would you place your head directly on the focal point of my rig? Thans, I appreciate it, it's a pain the ass to aim this thing.
  • by Dunbal (464142) * on Thursday February 03, 2011 @09:26AM (#35089316)
    Yeah, I used to burn ants with a magnifying glass too when I was much younger than 19. Solar death rays are pretty common at that age.
    • by Sockatume (732728)

      I see from your signature that you didn't really get out of that phase. ;)

  • Didn't Cockerham do this already?

    http://cockeyed.com/incredible/solardish/dish01.shtml
  • With a focal length of about 3 feet it's not exactly a death ray.
    The reason this works and what the mythbusters tried did not has to do with the F ratio.
    A lens (or mirror) with an F ratio of 1 will concentrate the sun enough to make a very small spot.
    One with an F ratio of about 100 or more, not so much!

    BTW, I wonder how that shed he stored the thing in burned down? Maybe it was facing a window facing the sun about 3 feet from a wall?

  • I was using a "solar death ray" when I was 9. It's called a magnifying glass. Great for killing ants.
  • I guess someone should have told him to point the death ray AWAY from the window.

One man's "magic" is another man's engineering. "Supernatural" is a null word. -- Robert Heinlein

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