Saturday Morning Science Experiment: Melting steel with the sun

Remember the satisfying sizzle of ants under a magnifying glass? No? Is that just me, then? Whatever, haters.

ANYway, the same science responsible for frying ants is at work on a larger scale in this clip from James May's "Big Ideas" series. What you've got here is a solar furnace, a carefully arranged array of mirrors that catches heat from the sun and reflects it, focusing it to point—effectively taking a lot of disparate, comfy sunbeams and gathering them together in a tight bundle. By their powers combined, the reflected beam can reach temperatures of 3,500 °C (6,330 °F). Watch in wonder and terror as the beam turns a hot dog to char and melts steel.

Thumbnail courtesy Flickr user gi, via CC


  1. Yes I remember the ants…their tiny cries haunt my dreams, and the odor of their sizzling proteins shall be with me always.

  2. The story said that the Archimedes more than two thousand years ago used this principle to burn enemy ships.So he first discovered this,at the same time he was the first to create weapons of mass destruction.

    1. Mythbusters tried that a couple times. It barely caught the ship on fire, and it wouldn’t stay on fire for long.

  3. Let’s hope the ants don’t unite and wage preemptive war against us after they get wind of this doomsday weapon.

  4. Okay, the puns on this one could go on forever, considering the number of words that start with ant-. :-)

  5. You’re all missing the point:

    The 2-Second (Solar-Cooked!) Hot Dog.

    (Get Sabrett and Nathan in a bidding war.)

  6. Y’know, fooling around with this kind of tech is what destroyed ancient Atlantis! Right, Chief?

  7. I’m pro-getting-James May to tell us more about interesting science stuff. From Top Gear to his toys show and this James seems like a genuinely likeable sort of fellow, a more specialized variation of Stephen Fry.

    So you know, screw the ants I’m more pro-James.

    1. Please don’t compare Stephen Fry and James May. Stephen Fry is an intellectual and a writer among many other things. James May is just an entertainer.

      1. There are so many things wrong with that, I don’t know where to begin. I guess in the order that you presented them.

        Being an intellectual: what do you mean by that, exactly? claims that as a noun, it means “a person who uses the mind creatively” Both qualify, but there’s no real cachet to that. It just means they’re not dribbling morons. Big whoop. Even if either or both are Mensa members, that’s not difficult and doesn’t make the member any better a person.

        Being a writer: both are authors with about ten books each to their credit. Again, there’s no magic badge of awesomeness that you get from writing stuff. If there were, I’d be glowing magically from my BoingBoing comments alone. There are great writers, and lousy ones. There are great people, and nonentities. There is no relationship between those two sentences.

        Being an entertainer: strange that all three traits you chose are shared between both people. Both trip the light fantastic on stage and screen. So what?

        Sounds to me like the differences you’ve tries to outline tell us more about yourself than either of these people: they reveal unabashed snobbery. Are you sure your name’s not Clarkson?

  8. That’s not James May. That’s Jeremy Clarkson. Yeah, I love him, just because he’s so unabashedly sarcastic and yet always so enthusiastic at the same time.

    Spot the sausage continuity error.

    The melting steel sound feels like a Foley effect to me.

    1. That is very definitely James May. If it were Clarkson, they’d have tried to put him in front of the beam.

      I like JC, for what it’s worth.

      1. GeneralSpecific wrote: “That is very definitely James May. If it were Clarkson, they’d have tried to put him in front of the beam. I like JC, for what it’s worth.”

        Oh… my… goodness. After two comments like that, I had to go and watch it again, to “prove you wrong”. My mouth dropped open: even from the first second of the voice, it’s unquestionably JM, not JC.

        I was wring, and apologise to anyone I misled (hopefully nobody).

        But the scary thing is, before that, I’d have *bet my life* that I’d watched and listened to JC. Very strange, and not a little worrying.

        I think I just broke my mind.

    2. No, the fellow in the video up there – with the long hair – is James May not Jeremy Clarkson. James is one of the co-presnters (usually the nerdy one) on Top Gear. He generally is a bit of a nerd, more interested in the internal workings of a transmission than how much torque it can withstand delivering to the wheels etc.

  9. Mythbusters might have gotten it wrong. They concluded that it took a long time to get a fire started, and conditions had to be optimal. But Sicily has brilliant sunshine for most of the year, highly flammable pitch was used to make ship hulls waterproof, and there’s the element of surprise: if the soldiers have to focus their shields on one spot for 15 minutes, they can.

    Of course the problem is that the invaders have many more than one ship: if you can set only one or two of the ships on fire you just piss them off. And Rome wound up conquering Syracuse.

  10. Mythbusters didn’t get it wrong. This requires quite precise focus. Not that difficult on a stationary object but lets put that object on rolling seas. Then lets think about that ship trying to get away when a bright light hits them and it is pretty implausible.

    1. More to that — for the myth to be real, they would have needed to focus on an object a significant distance away. This is much, MUCH harder than focusing on something only a few feet away.

    2. Greek fire, a completely different WMD of classical antiquity, has never been fully understood. It’s generally assumed that it only worked under very specific conditions, both atmospheric and strategic.

  11. @Joe the Mythbusters tested the concept in the context of ancient technology, which meant many limitations in construction.

  12. Funny story: reminds me of the time I meant to use my x-ray vision to see through someone’s clothing, and accidentally…


  13. There are ways (within the technological reach of Archimedes) to aim a mirror to direct sunlight onto a distant target. Mythbusters didn’t use those techniques, and they failed.

  14. I’m surprised no one’s tried to call it a “green laser” yet. Green as in ecologically friendly, not 532nm. Regardless, it does get my inner pyromaniac awfully excited. A similar sort of device could be used to drive a steam-powered device in situations where an open flame may not be practical.

  15. Sweet. James May has a new science show :googles:

    btw this is my favorite James May science bit, by far. Somehow Top Gear talked the US Airforce into letting James May into the stratosphere @ 80,000ft in a U2 Spy Plane Trainer:

    Nobody will deny Top Gear has a flair for the dramatic, but damn if they don’t make good TV. May’s stuff tends to be less funny, but much more interesting than Clarkson’s.

  16. It seems to me that obviously Archimedes must have been able to reproduce the effect to some degree otherwise he wouldn’t have known about it. It’s like saying Archimedes just took a wild guess one day that he could create pictures on a screen with electrons. 2000 years later he would have been correct. The myth started in the 2nd century by Lucian so someone somewhere managed to catch something on fire using reflections. None-the-less it would have been great psychological warfare. Would you want to go to war with a city that claimed to have magical weapons only to have one of your ships hulls inexplicably catch on fire?

  17. …You know, normally I don’t get into the MAKE scene like the rest of the BB crowd seems to, but this is one project I may just undertake. Except I won’t be melting steel. Instead, a much more fun and deserving target would be wasps and wasp nests. Anything to have *real* fun nailing the little bastards that I happen to be hyperallergic to.

    Think of it as a home-tech anti-aircraft weapon toy that’d be more fun to play with than a Johnny Seven OMA…

  18. I noticed in the video the “steel” did not turn red then white before melting, but instead stayed metallic coloured throughout the heating…

    Which is weird. As far as I know, steel doesn’t do that.

    But aluminum does. Or, in this case, aluminium.

  19. So you basically could use this to boil water, to make steam, to turn a turbine, to make electricity, with zero emissions. No need for coal.

  20. Why not have a huge glass built in the sky that can scan an entire country, burning everything with the concentrated beam.

      1. Argh! Orbiting solar stations would answer all our power needs for millennia to come, with effectively no environmental impact. But uses like this…

        This is why we can’t have nice things :(

  21. Ah! Use it to separate hydrogen, store it, and run a hydrogen economy. Now ain’t that confusin’!

    Ooooohh James May, Jeremy Clarkson – first in line for my beaming atrocity spree. The former ruins the weekend papers with his vague and lazy writing, if he ever actually writes anything, and the latter … ruined jeans for 10 years.

    And they’re both antiquated. I spit.

  22. Anon @ 37.

    The steel is soaked in and reflecting way more light than it would be emitting from black body heat. That is the concentrated sunlight bouncing off the steel is way brighter then the glowing orange emitted from molten steel.

    The camera stopped down and stopped down and stopped down some more for that shot. It was cool looking and very different than what I would have expected.

    The after shot does look like melted steel not aluminum.

  23. Re: Archimedes & the ships – He may have thought of the concept and wrote about it, but it’s doubtful that it could have been put into practice. A parabolic mirror concentrates sunbeams at its focal point, so to use it as a weapon one would have to bring the mirror to the correct distance from the target for ignition to happen. Outside the focal point, not much would happen. Now, maybe mirrors could be set up to set fire to ships that came too close — but the sun’s movement across the sky would constantly change the location of the focal point, again limiting its practicality.

    I did read a few years ago of a parabolic mirror mounted on a servomotor to follow the sun, which was used to run a Stirling engine hooked to a storage battery. (The “hot” chamber of the Stirling engine was suspended in or near the focal point.) Under clear skies, it generates more electricity than it takes to run its own motor and power an AC all day long. Theoretically, one could use this to keep one’s house cool in the summer and eliminate the electric bill.

  24. Mythbusters did get it wrong because it has been done before.

    “This contention was dealt with in 1973, when a Greek engineer undertook his own experiment to get to the bottom of Archimedes’ death ray. He assembled 70 soldiers, each holding a 5-feet by 3-feet (1.5-m by 0.9-m) mirror. The concentrated beam reflected by the mirrors set a row boat 160 feet (49 m) offshore aflame. It is possible, then, that Archimedes’ death ray could have worked.”

    source: NPR

    In fact, it takes very little research to find other documented successful experiments.

  25. i see that everyone just sees this as a giant toy, or a weapon. well, israel has been using this technology for almost years, and they’re producing electricity with it.

    you keep on burning ships.

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