Episode 46: Archimedes’ Death Ray

Air Date: January 25, 2006

REVISITED: An array of bronze mirrors can set a wooden ship on fire. (From episode 16)


The large scale array simply took too long to light the ship on fire. On top of that the ship only ignited when it was stationary and positioned at less than half the distance described in the myth. The myth was plausible at a smaller scale, however. Flaming arrows were fired from a ballista at the ship, but to little effect. The most effective (and plausible with Archimedes-era technology) method of lighting the ship ablaze was through the use of molotov cocktails.

(This myth was revisited again in President’s Challenge.)


  1. Ninja says:

    I remember reading online a guy who made a solar ray. It consisted of mirrors positioned at precise angles onto one focal point. This allowed him to burn/melt things very easily, with a massive amount of heat. This was only man sized, so maybe if it were upscaled this could work. Unless this was what the MBusters did. I haven’t seen this particular episode.

    • kenn says:

      maybe they left out the oil used for lighting their way at night if this oil was store on deck then perhaps the feat was possible

    • art pluim says:

      Did you guys ever think that Archimedes might have had parabolic mirrors? A shield flipped over minus the straps might be just that. I would predict that a single parabolic mirror would set a sail ablaze. Same principle as a solar cooker.

      • Roger Pedersen says:

        Most shields weren’t metallic in the back, they were wooden. Only with metal plates partially or fully covering the front..

        Study how shields were made, there are quite a few commonalities when it comes to most shields from the Roman Scutum to the Spartan Hoplon..

  2. Hotspur says:

    It worked. The mbusters used a hokey substitute that looked like a disco ball cut open and pasted on a satellite dish for an equivalent. Good science. I don’t recall what the substitute target was.

    I was expecting a different outcome because I saw the experiment successfully performed (on PBS I think). They used highly polished shields such as existed and concentrated the ray on a replica Roman ship built to scale out of authentic materials.

    All this took place in the Syracuse harbor.

    It worked just fine.

    • TLB says:

      Archimedes knew all about parabolas. From his Wikipedia entry:

      Archimedes is generally considered to be the greatest mathematician of antiquity and one of the greatest of all time.[2][3] He used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi.[4] He also defined the spiral bearing his name, formulae for the volumes of surfaces of revolution and an ingenious system for expressing very large numbers.

  3. jamoecw says:

    they also keep on thinking that the ship was moveing, it was a seige not a naval battle. period seige strategy had stationary ships mounted with seige artillary firing at the walls and defenders. also the boats would be closer than a bow shot due to the fact that they were firing up at the defenders, which meant they would have to be closer due to the arch. on top of this they did not test against the ropes, wich are not white and are made from fibers which catch fire much easier than wood.
    also the ray did burn the wood at the original range, which means that even their array would be quite capable in a seige, if they targeted the decks in order to eliminate the soilders operating the equiptment, or even catch fire the equiptment itself.

  4. michael says:

    Lots of archeological facts and possabilities left out I have to side with your sceptics. Not busted to us.

  5. Robert B says:

    Did the team take into account the time of year and the latitude that Archimedes’s was at when he used his death ray? If that info is available. Also, at that time where not the ships sealed with a pine tar or a pitch that would probably light quicker than bare wood. I really like this episode.

  6. Another Michael says:

    What about aiming at people. Not very polite these days, but hé, in those days it was war. Moreover, there is much more to burn than sail and timber. Rigging, barrels for instance.

  7. Glenn says:

    Even taking into account flaws in the shields, distance, etc, a properly trained unit of the army (easy to consider with the Greeks) could focus 100+ polished shields at one point. This can be accomplished by proper military training: The first soldier in the line starts by casting the light from his shield on the ground at his feet, then moving the shield until the lights rests on the target. Immediately after the next soldier in line does the same, and the next, and the next. It would only take a second or two for each soldier. In no more than a minute they could effectively magnify the light hitting the ship by 50 times. And there is no point in trying to hit the ship at the water soaked waterline. Better to set fire to the dry, easier to burn ropes, sail, and material on the deck.

  8. William R Alcorn says:

    Have u thought of simply a realy larg flexable matter such as a trapalean poshined on its side faceing the sun with a mirror like pain or better yet crome that when pulled from the center it creates a cone of light like a magnafieing glass will at a certan distance from the object it witch you are trying turn burn so it can be a consintrated beam of light?
    key piont pull from the exact senter of the trapalean. please for give my spelling

  9. john says:

    Not only plausible but most likely confirmed!
    In 1973 a serie of tests was run by a greek engineer dr. Ioannis Sakkas.
    He used 50 bronzed mirrors on a smal boat.
    In about 2 minutes it was in flames.
    A greek professor Evanghelos Stamatis said he had no doubt that Archimedes used solar power to destroy the Roman fleet.
    Most likely he used polished bronze shields.
    This was described in a book published around 1976 by the Reader’s Digest Association Ltd London

    Greetings from Texel, Holland

  10. David says:

    john you are wrong!!!! the way the arcamiedies would burn roaman ships is to first use thier catipalts to cover the ship an sails in flamabal luiquid like oil then have thier archerars fire flaming arows at them burning the ship and th men would jupout and fley so that is ay jhon is wrong!!!!!!

  11. Geoff says:

    David why are you such a mature member of the community? As for wrong, your first post is what is wrong with kids today and why parents need to be able to beat their kids when it is needed.

  12. Daburto says:

    I would love to see the Mythbusters recreate Dr. Ioannis Sakkas’ experiment, as it apparently succeeded in accomplishing exactly what Archimedes allegedly achieved. Surely Adam and Jamie cannot be satisfied to allow a Greek engineer in 1973 to achieve something that they haven’t been able to.

  13. ashley says:

    A friend and I are trying to use mirrors to set a piece of paper on fire for a physics project. Do you have any advice for us? I read your report on the mirrors for the ship and wood. I’m just not sure if our experiment will work.

  14. Doug says:

    Just saw on episode re-run. What was that useless monstosity they built? A little research on the word “concave” may have been in order. May have led them to Nimrud lens

    • Chris says:

      I agree – the curve was wrong – should have concentrated the sunlight onto a centre point – not dispursed it

  15. John says:

    Sorry guys, this is rubbish
    Adam Hart-Davis carried the experiment out in a matter of minutes on British TV

    And Jamie, you are quite correct, Archimedes did use a much simpler explanation than the outrageous rig the Jamie built, he used polished shields with lots of trained soldiers, not idiots trying to have fun.

    Most of your stuff is interesting, this is just plain wrong

    • ton says:

      Could you give me a link? I want to know how they manage to coordinate and aim at a moving target from far away.

  16. Richard says:

    The Archimides death ray IS FEASIBLE. I just watched the Mythbusters episode 16 where MB could not get the collection of mirrors to focus the sunlight properly. I am watching Discovery Science in Ukraine and amazingly the next day (Jan 27th, 2009) I watched, on the same channel, an Australian guy successfully focusing the sun’s rays using an almost identical set up, to provide solar power for ‘Megapolis’ – the series about future megacities. One of their biggest problems was precisely far to much heat from the sun ray focuser which resulted in all sorts of things catching fire! MB needs to revisit this as it definitely looks plausible. Richard

  17. Johnboy says:

    Adam Hart-Davis (what the ancients did for us ,BBC) created a minuture array of mirrors and a miniture ship. Set it on fire perfectly.

  18. skeptic says:

    it could have been 1 million polished bronze shields too..

    little did you realized that the time, economical and technical constrains back in those days wouldn’t allow them to even have lots of polished bronze shields?

  19. Haziq says:

    Mythbusters! I love wat u do!!!I wanna be a future mythbuster!!!

  20. Alan Small says:

    You claim this busted but you never did it with the resources available to this genius. He had a legion of well trained, professional soldiers.
    rimming a large round shield with leather, laying down a round sheet of bronze or copper then attaching a center hand grip would produce a a slight parabolic shape that would focus light 100s of yards away. A legion of soldiers (not a bunch of giggling volunteers) all concentrating on maintaining their individual reflected light on the target (not one huge array).
    Go to VMI or West Point and get disciplined soldiers and plenty of them thrn try it as Archimedes would have really done it before you arrogantly declare a far more brilliant man than yourself “busted”.

  21. Mike Smith says:

    There was an alternative energy programme in UK hosted by James May which showed a mirror array pointing towards a water tower which instantly turned the water into steam to drive a turbine and generate electricity. I believe it was in Europe (poss France) but definately worked. So Archimedes myth is very plausible.

  22. Luc Botes says:

    This won’t work for you but anyway. Imagine a whole city holding up 2 metre mirrors. Surely this would work. Somebody has exaggerated about good archimedes was.

    • Luc Botes says:

      This won’t work for you but anyway. Imagine a whole city holding up 2 metre mirrors. Surely this would work. Somebody has exaggerated about how excellent Archimedes was.

  23. love says:

    system error on this: greek ships were covered in tar or bitumen. much easier to ignite than just naked wooden planks.

  24. m0nkey says:

    though i think arcemides soz about the spelling waz a great man who desrves respect but i dont think that the death ray waz real az it haz to be so spithic lik location, time, heat i mean wat if the romans ataced in the middle of the night then wat ur stuffed arnt u

  25. yankyourchain says:

    On “World’s Toughest Fixes” with Sean Riley, episode “Solar Power Plant”, they set a block of wood on fire instantly with a half-meter parabola mirror. Distance was short, but goes to show that precision is everything.
    Trouble is to get the mirror and ship aligned – nearly impossible.

  26. Phil says:

    I agree,.. this isn’t terribly effective if the invading army attacks at night. However, what about something as simple as “multiple refraction”?

    For example,.. instead of having 100 soldiers trying to focus their shields at a ship a few hundred yards away,.. what if those same soldiers stood with their backs to the ships and focused their individual shields at a single concave shield only a few yards away (and about 10 ft higher.) This way, all of the light from the individual shields could be easily magnified and amplified into the one larger shield. Then you would need only point the single larger shield at the ship you wished to destroy. And because the shield is elevated, the “death ray” would pass over the heads of the soldiers, thus keeping them from harm.

    I think Archimedes would be smart enough to figure something out as simple as “multiple refraction”.

    Just a thought,…

  27. ali says:

    mythbusters don’t know much about physics.
    the one year i took in physic prooved many myth’s plausible.
    this one is plausible if they used slightly curved mirrors, they used flat without even considering it.

  28. mojo 306 says:

    archimedes would have been smarter than that he would have tried to light the sail on fire. and was that wood treated?

  29. klang says:

    What struck me when watching this, was that the mirrors they used were modern glass…ie perfectly flat, where assuming the myth is true the mirrors would have been of the glass available then – look at glass made as recently as Victorian times – each piece is flawed, thicker in some areas than others. I feel this would have made the mirrors much more likely to focus the sun, as they would have been acting more like reflective magnifying glasses. I would love to see the experiment again using glass like this.

  30. John says:

    With regards to the ship used for all the experiments, there are some period items missing. When any navy of the time was sailing they carried various materials on deck (straw, flax, etc) especially because they carried live animals with them to slaughter for food (no refrigeration 2 millennia ago).

    Both of these materials are readily flammable at much lower temperatures than those generated during the last experiment. Stacked straw and flax tend to generate internal heat. So it is more likely that the contents of the ship were targeted rather than the hull of the ship itself.

    Bronze mirrors (from the insides of shields) have a number of things working against them to be used as efficient mirrors, but focusing reflected light from a number of shields onto a sender (concave aiming mirror) would have been more likely (simple).

    Egyptians and other races used the same method to light underground chambers with great efficiency (no electricity) because burning oils in an enclosed area was a problem due to the eye and lung irritation.

  31. Dillon says:

    Why didn’t the rocket scientist’s large scale adjustable focus death ray get rebuilt and tested? I was really looking forward to it when the voicover said it had been raised from the dead, but they never showed it being tested.

  32. Shawn says:

    This “concave aiming mirror”dose not exist.There is no mirror ,with any shape,that will take light coming in from all different directions,and reflect it back in one single direction,or to one single focal point.A hundred shields,reflecting their light on a concave mirror(parabolic,hyperbolic,whatever)will have a hundred different focal points. I designed,built,and now use a solar cooker that is based on 36 ,8″x8″ mirrors ,all mounted on universal joints.It will catch cardboard on fire in less than 2 minutes.I can adjust the focal point to any point I want. Although I can use my cooker to eliminate tent caterpillars 30′ up,I have never set one on fire.The point is,I got rid of them. I have also been lucky enough to have been a rower on the Greek trireme “Olympias”.I was a Thranite ,which means I sat in the top of 3 rows of rowers and was very exposed. I think all that was needed to knock out a ship would be the reflections of a hundred or so shields all pointed at a few of the rowers near the stern.As for the myth,it could be an embellished war story which is at the same time possible.

  33. Jeff says:

    If each soldier held their shield backwards, each one would generate a focused beam due to the concave surface. When the concentrated beams overlap the effect would increase exponetially compared to flat mirrors which only reflect 97% of light at best.

  34. Hoshi_Reed says:

    The “death ray” hotel uses the same principle on accident. There is a hotel in Las Vegas, Nevada called the Vdara. that they built the building in such a way that the windows reflect the light and focuses it on the pool area. The guests get more then a tan if they stay too long. Given that a ship has pitch to seal the boat and has gunpowder and other flammables on deck… with determined soldiers who are disciplined I’d say that burning a ship is not that hard.

  35. Jay says:

    As i watched the revisited Archimedes Solar ray, i was wondering why Mythbusters chose the test run with small Mirrors, and then switch to Large rectangular mirror. The Sequence in which the volunteers aim at the ship’s sail is way off, and not stable. aiming at the sail in sequence, one or two at a time to get their aim in place, then more can follow to aim at the spot, and so on… that way, the sail get aim correctly and heat can be build up as each person aim correctly. as for the large mirrors, I’d say consider smaller size as in a circular shield, to get a focus circle onto the sail. And again, aim at the sail one at a time, to aim it correctly for maximum heat!

  36. Jim says:

    Hey you guys:

    What are you thinking of re: Archimedes’s Sun Ray?

    The Greeks came up with the parabola, right?
    The first parabolic mirror was Greek, right?

    The first parabolic mirror concentrated light, right?

    500 parabolic mirrors would concentrate a lot of light, right?

    If the Greeks turned their sheilds around and polished the concave side of the shield it could have produced a parabolic mirror, right?

    Les Stroud started a campfire in South
    Africa by polishing a Coke Can bottom, which is concave, with a bit of cocolate candy bar, making it slightly parabolic mirror, right?

    Brad Pitt used the back of convex shields in “Troy,” right? (concave surfaces)

    Polish the concave sides of the shields to parabolas and then shine them on the ships is my recommendation.

  37. Susan Clark says:

    This was successfully performed here in the UK by Adam Heart Davis. Mythbusters weren’t using the correct sort of mirror and they didn’t focus the sunlight to a small enough area. When performed correctly the energy from the sun is like a pin point of a laser beam. I still love Mythbusters! They Rock!

  38. Remco says:

    no offense but using solar rays would have been pointless. at the time there were several far more effective, cheap, lightweight and garanteed ways to set a ship ablaze, independed of clear weather conditions. amongst them were air powered ‘cannons’ capable of spraying a large quantity of flaming oil well within its current sea siege distance (an easy 20 meters: keep in mind that ships had to get real close to perform any type of siege attack and roman siege vessels used to link up to enemy boats in order to synchronize themselves to the enemy vessel. they used heavy walkways with large nails attached to them, much like a claw, large towers and mostly arrows. dont confuse every old ballistic weapon with the ones youre used to seeing in items on ancient weaponry. stick to the ones that the romans could have actually been using at sea during that specific time period: during that time a ‘quick’ siege on water would easily take around 16 hours).

  39. dirk says:

    First of all, lighting a ship with many mirrors, would make it practically impossible to do any aiming by soldiers on the boat as they would be looking into the sun al the time. This makes the ship vulnerable to enemy attacks. As the ship would have flamable material for catapulting on board/deck, that would be the stuff to aim on with solar heat. Not the thick wooden sideboards or the sails.

  40. Malcolm says:

    Both times mythbusters have tested this myth, they havent used precise methods of alligning the mirros to a single focal point in order to capture the heat at a single point. Basically love to see them retest this myth with this actually being achieved.

  41. Mike says:

    Nearly every kid burnt things with a magnifing glass. When used on a larger scale, say tied to a mast, a parabolic lens could definately burn into a wooden hull. Especially if you had mirrors to help aim light into the lens.

  42. bikemike says:

    In india , there is a ancient method of polishing both copper and brass into silver mirror surface.
    The tequnice has been around for thousands of years.

  43. James C. says:

    Am I the ONLY person in the world (including the US president) who noticed that Mythbusters didn’t actually test the real “Archimedes Death Ray” myth, and so couldn’t have busted it one way or the other? The REAL myth is that a flammable liquid known as “Greek fire” was spread on the water, and then the beams of light were used to combust the flammable liquid, and so burn the ships. How could they possibly miss this? Why didn’t they test the original myth, or was it too technically difficult? Am I the only person in the world who actually reads?

  44. MR C says:

    hi all i am an inventor, the truth to this mystery is very sinister indeed. Obama is a lire and of course the idea was perpetuated as many giant mirrors. obviously the fact remains that i had also reconciled the hidden message. the smaller the mirrors the greater the power. end story.

  45. MR C says:

    now that i think of it, the invention that comes to my mind a solar dish powered by a few led light. out put will be way more then energy used i guarantee it… can then boil water! on a few volts only.. use a jewel thief circuit in connection to the led lights positioned at the focal point.

  46. Daniel says:

    Interesting dates:
    glass bottles and utensils 3000 BC
    parabolic history 380 BC
    Archimedes — 287 BC – 212 BC

    If Archimedes was only as smart as am 8-year-old his death-ray would be more of a huge magnifying glass.

  47. nathan says:
  48. Ascension says:

    Problem: Jamie is on the ship in his suit and saying “it is very hot….. all the mirrors are shinning …… I’d call it busted…..”

    Observation: I count maybe ten mirrors actually reflecting the sun (( They are the dazzlingly bright ones )) the rest of the mirrors are reflecting blue sky…. thus no heat.

    So Obviously the Mythbusters are doing more bogus science yet again pawning it off as proof positive… Or Busted as the case may be.

    Proof: We use an array of mirrors aimed at a tower to boil salt. Which in turn boils water —> creating steam —> spinning turbine —> creating electricity.

    1st step: Each mirror, ((size used in the revisit will work)) has a hole drilled trough it’s center for the holder of the mirror to sight through.
    2nd: on the mirror side a black X is placed around the eye hole.
    3rd: A sighting stand, ((a stick on a weighted stand with a clamp on top)) is placed five feet from the mirror. On this stand is a six inch circle of white, with a two inch circle cut out of its center.
    4th the mirror holder sights the ship both through the mirror hole and the white circle ring. Directs the sun beam to cast the X shadow on the ring of white.
    5Th: this ensures the fullest amout of sunlight is targeted at the ship which is sighted through the rings.

    Since each mirror holder must target the ship separately each has their own sighting ring.

    To avoid cutting holes through the center of so many large mirrors, start with ten mirrors and work your way up.

  49. ZGMF1017 says:

    It’s obvious they needed:
    A) Smaller Mirrors
    B) A better way of angling said mirrors.

    The focus point of something like that implemented properly would be far smaller than the whole side of the ship they had.

    It’s been proven to work by Adam Hart Davis in What the Ancients did for us back in 2005.

    Not to mention a power station high up in the French Alps that uses such a technique to boil water to produce steam and thus create electricity.

    Myth busters need to occasionally go small and precise not over sized and awesome…

    On A side note, if anyone has seen the original Gundam anime series you might have heard of a super weapon called “Solar Ray” which uses a massive array of mirrors in space to focus on a specific point to melt enemies. However it only lasted for a brief period of time before the mirrors themselves where melted.

  50. Mark says:

    if the mythbustersresults can’t make a parabolic it’s normal that it will not work.
    in italy in the 90’s they made it right. heading towards a replica of a Roman ship (with the same materials that were used at the time) 24 polished metal panels in material similar to those used by sirausani as shields. After a few seconds the wood began to emit smoke and then burn.

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