Man unveils 30-year-old "instant water boiler" invention

Ninety-two-year-old Peter Davey of New Zealand says he invented a unique water boiling gadget 30 years ago. He claims it uses sound waves, not a heating element, to boil water in seconds.
Picture 5-54Davey noticed as he played the saxophone at home that everything resonated at a different frequency.

"The glasses will tinkle on one note. Knives and forks in the drawer will tinkle on another note and I realised that everything has its point of vibration," he said. "In the same way, a component in the ball is tuned to a certain frequency."

A retired engineering professor, Arthur Williamson, was invited to look at the boiler in action. He said:

"I don't know enough about sound to know whether you can transfer that amount of energy via soundwaves. I doubt it," said Williamson.

He did remember an alternative kettle years ago that had two perforated metal plates inside. The power ran between the plates, through the water. "The resistance through the water provided the load. I wonder if it isn't working like that? Without taking it to bits, you can't tell."

Someone, please, take it to bits. Link


  1. That’s interesting; hitting water with waves of its resonant frequency are how a microwave works. Could sound waves really carry as much energy as photons?

  2. I am no expert, but I could see the water molecules being excited by a specific frequency and being heated via collision. That would have to be one high frequency to work so fast, though.

  3. However it works, it does appear to work.

    Interesting how they didn’t seem to know how to end the article & just started talking about his house.

  4. Who looks at a tea kettle and thinks “This could be a bit more sonic”?

    (sorry, obligatory Doctor Who quote)

  5. As long as you can transfer enough energy to raise the vapor pressure of the liquid to atmospheric pressure, it doesn’t matter how quickly you do it. All you need is a method of near-instantaneous energy transfer. To wit: the microwave, or better yet the hydrogen bomb… of which this item is neither, since those transfer energy via EM waves, and not sound waves, which are physical pressure oscillations.

    I doubt he’s using only sound to do it. Low frequencies would probably just disturb the water a lot. The higher you go, the potential is there for a smoother energy transfer to the water (like the sonic mixers in #8 AM’s link), but if high sonic frequencies cause water to boil, then every pregnant woman getting an ultrasound is boiling her baby!

  6. “the device looks oddly like a bent desk lamp, with a metallic ball at the end instead of a lightbulb. When plugged into the power supply, and the ball is lowered into water, it boils the liquid within seconds — even as little as a tablespoonful.”

    in other words, a heating element

  7. My money says he’s essentially put a resistor inside a cup of water. Sort of like one of these.

    That said, you could in fact heat water by moving it around. Lord Kelvin observed that water at the bottom of a waterfall is warmer than it is at the top. This is because in the microscopic sense, temperature is velocity.

    That said, I tend to doubt the velocity of the speaker is high enough to heat the water, but I could be wrong.

    The sonic refrigerator works on principles of physics which are well understood. It’s friggin’ sweet, but not a mystery as to how it works. Well, it is to me, but I haven’t really read the papers, but I think it’s basically pumping on a coolant, just in a fancy way. By sonic they mean ~60 Hz, not something crazy high (I read that far).

    A couple more points:
    @1 Sound waves are the mechanical jostling of particles against each other, collisions of particles are actually how heat is most efficiently transfered (for example, the space shuttle has a hard time bleeding off heat because it is in vacuum). Also, microwaves work near the resonant frequency of water, 2.45 GHz happened to be unassigned to anything else so they operate there so as not to interfere communications and the like. I’m too lazy to look up the resonant frequency of water.

    @2 Microwaves operate in the gigahertz. You are not going to mechanically drive something in the gigahertz without being pretty damn badass.

    @6 It only matters how it works in that he is claiming to have discovered a new physical principle. It would be nice if he showed us the guts so we could know what’s actually going on.

  8. Tht Wllmsn fllw s n gnrnt ssht. f crs t’s pssbl! Ultrasonic welders have been around for years and generate great amounts of heat in order to melt and fuse plastics. Has anyone done a patent search? He must have one.

  9. @Imhotep –

    Really, do you want to turn this into name calling?

    Actually I did do a patent search. Couldn’t find one held by this dude, I looked in both the USPTO database and IPONZ.

    Ultrasonic welding is based on generating friction between two pieces of polymer, causing them to heat up. The frequencies involved are tens of kilohertz, well below the resonant frequencies of water that other people were speculating about.

    I’m skeptical of explanations of this that use frictional heating. If that works, why can’t I warm water in my blender?

    See, we don’t need to resort to name calling.

  10. There are 2 ways in which this device could work:
    1) It makes the water look like it is boiling
    2) It actually boils the water

    In case 1, ultrasonic waves create cavitation, or rapidly expanding and collapsing vacuum bubbles. You can see a really cool example of this here:

    It could also work like an ultrasonic mist maker and give the illusion of steam production( .

    In case 2 it might actually work, I have heard reports of the water around ultrasonic humidifiers feeling hot where the sound focuses. Then again this could be a sensory illusion due to the high-power ultrasound(which can tear apart cell walls). I also found this report on using focused ultrasound to heat a spot up to 120 C in seconds to kill cancer cells.

    Of course, it is dubious if the device could actually focus ultrasound.

    If all else fails and this device does not actually heat the liquid up, it could at least be used to stir stuff up and possibly enhance flavor, as high energy ultrasound devices called sonicators have been used to emulsify, produce colloids, eliminate crystallization in honey, or potentially make the best damn coffee in the world.

    More information on this device is definately needed.

  11. Simple electrical coils that you immerse into your cup have been around a long time. But they take time to heat the water to it’s boiling point. But his device boils water in seconds. Given my crappy record you’d think I’d learn but… I guess not… I think he is doing exactly what he says he is. Using finely tuned harmonic sound waves to rapidly heat water.

  12. Water. It heats up for several reasons. The stove? The microscopic hammer hits times ten billion of the bottom of the pan, combined with invisible infrared heat given off, which effects the vibration of it’s bonds, which quickly dissipate as heat.

    A microwave oven is a modern marvel. It uses a similar frequency to your cell phone, only with a HUGE transformer and (without a circularly rotating tray), areas of heaven or hell. A microwave oven hits exactly the ROTATIONAL excitation frequency of the boomarang-shaped water molecule. So what does it do? Rotates around like crazy, hitting every other neighbor molecule, and what happens when you “add energy” to an unwatched pot of water? It BOILS.

    Want to try the worst food ever? Scrambled eggs in a microwave. Add salt and olive oil first. It wont help the texture, only the taste. Packing peanuts or unpopped pop corn come to mind.

    In THIS case, because it’s sound…but first I digress…the Sun is also like a drum, vibrating with audio waves, and so is in some sense that I forget is the entire universe…but indeed you could heat a small vessel using sound waves, as long as the frequency of waves exactly match the sound (or a multiple of it) wave spacings.

    This is not perpetual motion. It’s kind of cool, and could be used for one or in parallel, several expressos in a row, and actually work, but isn’t that what simple fire is for?

  13. @ noen

    Then what is the harmonic frequency of water? Propose an experiment to measure it or a way to calculate it. Or point to a reference where they do.

    I think you’re confusing the fact that water does have vibrational resonances, but they are generally in the IR or so, which is a relatively low frequency from the point of view of optics is still orders of magnitude higher frequency than sound.

    If water had acoustic harmonics, they’d be easily measured.

    @ morehumanthanhuman

    What’s this about sonication and coffee? Where can one get a taste?

  14. @ NikFromNYC

    The microwave isn’t actually at the exact rotational frequency of the water, just close.

  15. I’m sure he’s intelligent enough and it was only a demonstration, but the image looks like he could burn himself shortly with a glass of boiling water.

  16. this is possibly what kurt is referring to
    “The device looks oddly like a bent desk lamp, with a metallic ball at the end instead of a lightbulb. When plugged into the power supply, and the ball is lowered into water, it boils the liquid within seconds — even as little as a tablespoonful”

  17. safe, commercially viable resistive heating elements heat relatively slowly. Elements with little shielding would work faster – and be more dangerous.

    mmmm… magnetostriction?

  18. “…even as little as a tablespoonful”

    A small amount of water is easier to boil than a large amount. especially as little as a tablespoon.

  19. two plate electrodes a millimeter apart and a pinch of salt surreptiously dropped in – or painted on the sphere?

  20. classic stage magic; it isn’t really happening, all the “witnesses” and “reporters” are in on it or dupes.

  21. My first though was, as AM mentions above, something related to either Resonant Macrosonic Synthesis (RMS) or thermoacoustics.

    I’d done a piece for WIRED ten years ago about the RMS torpedo-shaped resonance chambers that Macrosonix used to create significant overpressures (that could be used as clean compressors, powder pulverizers, and other applications).

    One quote I remember from Tim Lucas came from the NPR All Things Considered piece that had originally alerted me to this technology. In that piece the technology was presented as being “the loudest sound ever generated” (though not heard, since it was generated inside the torpedo-shaped chamber). When asked what it would sound like, were it possible to be inside the chamber, Gregory Swift (at the Los Alamos National Laboratory) had replied, “If you were able to somehow find yourself inside the small resonating cavity of this device, hearing loss would be the least of your worries. Your hair would catch fire.”

    And this points to the thermoacoustic nature of what might be happening to anything that’s inside a shape that’s resonated in this manner. Lucas had done a great deal of research at the Los Alamos National Laboratory, in the Thermoacoustics Laboratory, experimenting with differently-shaped resonance chambers.

    He found that cones and torpedo shapes allowed the sound inside to be driven to resonance. Esentially like a laser, but with sound waves instead of light waves. Previously, greater amounts of energy introduced into resonance chambers had resulted in the collapse of the waves (instead of being driven to resonance), and this resulted in the energy being given off as heat (hence, thermoacoustics).

    Perhaps something like this is happening here.

  22. Nine times out of ten, if the inner workings of someone’s invention are a secret, there’s something fishy going on.

  23. or a sphere within a sphere, the water quickly heated by a conventional element to boiling, dropping from a center point (can’t see if there is a hole in the sphere) and unboiled water being drawn up a capillary space between the nested spheres by difference in relative pressure,flash boiling,drawing more water up…..

  24. Tefal offer a kettle that provides hot (not boiling) water for teas and coffees in three seconds. From the notes provided at Amazon, it seems to pipe water through a hollow spiral heating element. Not quite the same tech as that from the gent above, but an interesting innovation nonetheless, and in the marketplace now.

  25. NikFromNYC:

    You can make great scrambled eggs in a microwave. I do it all the time. So do most of the cafes I know of. You just have to know HOW.

  26. Another day, another crackpot on the internet.
    There’s not enough info in the article to debunk this, but in general:
    The problem of boiling water is not how to get the energy into the water (microwaves or submerged resistors work quite well), but how to get enough energy. A wall socket only delivers so many Joules per second, and heating an amount of water from room temperature to boiling takes a set amount of Joules, no matter how you transfer them.

    If I had a gun to my head (which I don’t) and had to make a guess, I’d say that this device vibrates with enough energy to cavitate, which creates bubbles of gas (water vapour) in the liquid. To the casual observer, this makes it look like the water is boiling. I’m betting the poor retired professor didn’t get to use his own thermometer.

  27. new variation on the lazyweb:

    1) get an idea
    2) promote it as if it already works, including coverage on BoingBoing
    3) have the comment-thread commenters do all your R&D
    4) profit!

    step 4, as always, is optional

  28. The basic laws of thermodynamics still apply here.

    1 kilowatt-second of energy will heat 1 liter of water 0.24°C. The article says it boils water in “seconds”, so let’s be conservative and assume that it takes 30 seconds. Let’s also assume that the glass in the picture holds .5 liters of 25°C water. Assuming 100% efficiency, it would take 5.2kW to boil that water in 30 seconds. A household outlet, by comparison, is usually rated for 2kW.

    Therefore, I must conclude that he is agitating the water (using ultrasound), and not actually making it boil.


    After watching that video, I have to revise my calculations. There is only about .25 liters of water in the cup, but the water “boils” in just 5 seconds. Therefore, were he actually boiling it, it would take 15.6kW.

    What it looks like in the video is that the device just has holes which he is forcing air through. Note that the device is suspended from a copper pipe, and that the power cord looks a lot like a thick rubber hose. Also note that all the bubbles come from the gap between the metal sphere and the black metal cap over it.

  30. @Jakethesnake,

    You can actually heat water with a blender. It’s a pretty basic thermodynamics problem. What you need is a perfectly insulated blender cavity. Then, all the work done by the blender blades will go towards heating the water. Unfortunately, you don’t have a whole lot of power going through those blades, nor do you have a perfectly insulated blender, so it’ll take a long time.

  31. video seems to show some vapour (steam or just fine droplets?) above the glass at the onset of insertion. Bubbles look like forced air. He holds the device and regulates the height by hand instead of just plopping it in. A simple float-ball valve in the head of the device to avoid tell-tale hissing? “Cable” is big enough for conductors and air both. What is the ballon one device’s base where cable enters for? At no time does anyone else handle it.
    No view of other end of power cable.

  32. @ Scuba SM
    I realize you can heat water in the blender – I was trying to make a point that if agitating water were an efficient way of heating it, we’d be using blenders as tea-kettles.

    Or something like that. I was tired.

    But we agree on thermodynamics at least.

    @ Zan
    Good point about the power needed. Your numbers look good, they should put a stop to any debate about if he is in fact boiling water. My money says it won’t however.

  33. JakeTheSnake, yes you can heat water with your blender. This is similar to the experiment Joule performed to confirm the First Law of Thermodynamics.

    Zan, you forgot the latent heat of vaporization. The correct value comes closer to 130 KW for a 5 second full boil of 250 g of water (with the approximation of a constant specific heat for liquid water and no superheating).

  34. @ Bzishi, You’re also a bit off with the point about the latent heat of vaporization, if you take that into account, you’ll calculate how much energy it takes to turn the water into steam.

    And, yes, I know you can heat water in the blender. I’m pretty sure I said as much. But thanks for reminding me that it was Joule who performed the experiment, I think it is still an impressive achievement and it’s good to remember why a unit is named after him.

  35. JakeTheSnake:

    Oh yes, I see what you mean. I always take it too literally when someone talks about boiling water. Most people don’t literally mean that they have boiled off water when they talk about boiling water. They only mean that the temperature has been raised to 100 C.

  36. Takuan, why so violent, you’re usually so nice. Besides, everyone cracks when subjected to the comfy chair!

  37. Tak-kun,

    Write him a note. Peter Davey, Locksley, Dallington, New Zealand. It’s all in the article.

    On another note, is T on vacation? It’s been getting pretty wild and woolly around here for the last two days.

  38. what are the possibilities here?
    would it be possible to heat water to a high temp >80c in say, half a second?

  39. what are the possibilities here?
    would it be possible to heat water to a high temp >80c in say, half a second?

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