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Toys Science

Fun With an Induction Cooktop? 147

fishfrys writes "Besides generating heat quickly and efficiently in ferromagnetic pans, what sorts of fun things can you do with an induction cooktop? This seems like a pretty serious piece of electromagnetic equipment — boiling water can't be the only thing it's good for. I went to YouTube, expecting to find all sorts of crazy videos of unsafe induction cooktop shenanigans, but found only cooking. What sort of exciting, if not stupid, physics experiments can be performed with one? Hard drive scrubber? DIY Tesla coil? There's got to be something."
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Fun With an Induction Cooktop?

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  • Now you can cook chicken with a Tesla Coil! The possibilities are end... well, you're still only cooking things with a tesla coil. Maybe you'll become a master at it and keep the chicken from being horribly burned in the wrong places, or not cooked at all in others. You could be the first man to be arrested for aggressive chicken handling!
    • by EdIII ( 1114411 )

      You could be the first man to be arrested for aggressive chicken handling!

      Uhhh, I hate to burst your bubble, but in Texas they are already passed 5 digits for people arrested for Aggressive Chicken Handling. I hear Arkansas has a special prize for the millionth "customer" too.

      Of course Virginia is the only state that legalized it.

  • by RealBorg ( 549538 ) <thomasz@NoSpam.hostmaster.org> on Friday October 29, 2010 @04:31PM (#34067540) Homepage
    that's what i have found so far. normally you cannot use aluminum on an induction cooktop, probably because a thick layer of aluminum is equally as conductive as the copper inductor in the cooktop, however a thin layer of aluminum can be brought to hover itself away from the cooktop and / or begin to glow if held in place. my cooktop took no damage from trying this but of course - don't try this at home
    • by queazocotal ( 915608 ) on Friday October 29, 2010 @05:00PM (#34067972)

      For much the same reason - 'magnetic stainless' is typically said to be OK for induction cooking, and 'non-magnetic' not.

      This is due to the 'skin depth' (look at wikipedia) being thinner in magnetic materials.

      This means that in both steel and iron pans, which are magnetic, in addition to the high resistance of the pan material, the electricity doesn't go very deeply, so it's only passing through a thin skin of the pan.

      However - with very thin containers, non-magnetic stainless works just fine.
      I regularly heat up a large (non-magnetic) stainless washing up bowl that's maybe 0.5mm thick on my induction cooker.

      Any thicker and it doesn't work.

      My favourite utensil to use with it is actually a cheap 0.8mm or so thick steel wok.

      Heats up in seconds, and once seasoned, is quite non-stick.

      My second favourite is a large steel plate 6mm thick, again seasoned.

      • by noob22 ( 1749444 )

        I regularly heat up a large (non-magnetic) stainless washing up bowl that's maybe 0.5mm thick on my induction cooker.

        Washing up bowl? Please explain.

        • by treeves ( 963993 )

          It's a bowl used for washing up (washing dishes) in. It's a Britishism, AFAIK.

          • It's a bowl used for washing up (washing dishes) in. It's a Britishism, AFAIK.

            I think people wash dishes in most countries. It's a bad idea to do it in the sink directly, because you can chip your dishes really easily. I suspect a stainless-steel washing up basin would have exactly the same problem, which is why people mostly use plastic ones.

    • by i.am.delf ( 1665555 ) on Friday October 29, 2010 @05:38PM (#34068402)
      Once upon a time I worked in a metal foundry. There people used induction furnaces to melt all sorts of alloys for castings. Skin depth is key. If you have tiny skin depth in your material it will take forever for something interesting to happen. Step 1 find an insulating container which will not burn. Glass can work(assuming your metal melts before the glass does) or ceramic is better. Place fun things in it like steel wool. Turn on the coil. Be astounded by steel wool. Aluminum cans are thin enough to melt, but be cautious they can ignite in air and if they do you can be poisoned or otherwise injured by the alumina.

      I think it might be fun to use a thin metal implement in a glass bowl to cook something from a hot rod.
      • Re: (Score:3, Informative)

        by Prune ( 557140 )
        Uh, first of all, alumina is not toxic to humans as it's quite an inert material (as are many other inorganic oxides in general). It's only dangerous in physical terms if you inhale a quantity of very fine powder. Second, you don't need induction heating to be amazed by steel wool. If you spread it out (reduce the density so it has lots of air within its volume) it is fairly easy to light with a torch and it looks a bit like fireworks.
      • Branding iron?
  • ...off the roof of a building!
  • by Anonymous Coward on Friday October 29, 2010 @04:32PM (#34067560)

    I remember seeing induction heating used to make a block of ice glow red hot.


    Apparently it heats the trace amounts iron inside the ice so this only works with tap water. Not really sure if it would work with an iduction stove top though. Worth a try.

    • Re: (Score:3, Interesting)

      by skids ( 119237 )

      Neat. I imagine their are potential lithography applications. Or you could just inject a BB into an egg and cook it from the inside out for the ultimate in runny whites.

    • by Anonymous Coward on Friday October 29, 2010 @05:52PM (#34068542)

      There is a triangular piece of metal in the ice. It's a demonstration by Huettinger, a manufacturer of induction heaters.


      I think water would flash to steam before you got it to glow. Unless it was under enormous pressure I suppose.

    • by khallow ( 566160 )

      Apparently it heats the trace amounts iron inside the ice so this only works with tap water. Not really sure if it would work with an iduction stove top though. Worth a try.

      No offense, but if the ice were this hot, it'd melt and flash into steam. There's probably metal (not just trace amounts) embedded in the ice and that's what's glowing.

  • safer than your hand. modern induction ranges have safety mechanisms to prevent accidentally burning your hands or other non-cooking inductable materials, so you are probably limited to what will be perceived (by the range) as a skillet/pan/pot - large, ferrous surface.
    • Re:water balloon (Score:5, Informative)

      by queazocotal ( 915608 ) on Friday October 29, 2010 @05:14PM (#34068140)

      Not really.

      There is no 'safety mechanism' as such that stops it heating hands.

      The coil can safely be energised with no load.
      It won't get too hot, or anything, and it won't noticably heat your hand, or a duck, or anything non-metallic.

      (well, it would heat graphite blocks and such, but that's cheating).

      The reason for the device not turning on with no load is to prevent it heating up forks and other metallic implements that have been placed on the surface.


      • by Strider- ( 39683 )

        Also, I would assume, rings and jewlery that may be on your hands. Being a Canadian Engineer, I wear an iron ring, though it's non-magnetic now (closer to stainless I suppose) so I don't know how much an induction cooktop would do to it.

        Then again, I prefer the primal experience of cooking on a gas flame myself.

      • Re: (Score:3, Interesting)

        by Psychofreak ( 17440 )

        Blacksmith's induction forge: for the modern smith.
        http://www.youtube.com/watch?v=k4xsqw463Hs [youtube.com]


  • Hardware modding may be required. Remove ceiling or wall before use. If you try it, on your own head be it - I do not guarantee your safety.

    • By that, do you imply that you do guarantee his safety, if he did not try it on his own head?

      • by Surt ( 22457 )

        Sure, guarantee limited to original purchaser of advice, and not heirs or estate.

    • by RichiH ( 749257 )

      Wrong coiling. And the value in a coil is the coiling. So re-coiling means you are better of starting from scratch.

  • It's been carefully designed to be only usable in heating up pans and pots and maybe their contents. Maybe because a friend of mine got one that's so sentive that it sometimes decides his cooking isn't worth heating up!
  • by Anonymous Coward

    Try some unexploded WW2 shells, some walmart bullets, a kid with braces. An arm with a tattoo. A hamster that ingested iron shavings. You were looking for unsafe and stupid things to try, right?

    • by Dogtanian ( 588974 ) on Friday October 29, 2010 @08:16PM (#34069800) Homepage

      unexploded WW2 shells, some walmart bullets, a kid with braces. An arm with a tattoo. A hamster that ingested iron shavings.

      Raindrops on roses. Whiskers on kittens. Bright copper kettles. Warm woolen mittens. Brown paper packages tied up with strings.

    • by RichiH ( 749257 )

      > some walmart bullets

      You can buy bullets in a supermarket? I guess there are some things about the USA I will never understand.

      • by SHaFT7 ( 612918 )
        The walmart super centers are half super market, and half standard walmart. the bullets are in the standard walmart side.
        • by RichiH ( 749257 )

          I thought Wal-Mart was a super-market?

          • Walmart is an all-purpose general retail store. The larger Walmarts, or "Super-centers", have a grocery store attached to them, but it is not a standard thing. Bullets are typically found in the hunting part of the Sporting Goods section, near all the camping gear, fishing supplies, etc.
            • Bullets are typically found in the hunting part of the Sporting Goods section, near all the camping gear, fishing supplies, etc.

              Really? I've never seen them selling any reloading supplies...just cartridges. FYI..."bullets" are pieces of lead, possibly in combination with other metals, like copper. A cartridge is composed of a bullet stuck in a case (usually made of brass), gunpowder inside the case, and a primer on the bottom (the little button thingy that explodes and ignites the powder when the firing pin of a gun strikes it).

            • Haven't you seen that they're rebuilding all their standard stores into Super Wal-Marts? Been happening all around here for years. Most are now twice the size of the original, or more.

  • by guorbatschow ( 870695 ) on Friday October 29, 2010 @04:40PM (#34067684)

    Last time I used my induction stove to cook water for noodles, I put the power to max, all the while listening to music on my iphone via headphones. You know, those standard apple headphones with microphone and volume controls. Right when I put the power to max, the music went off. Turns out the volume was set to minimum. So I tried to restore the volume via touch controls, but it went to minimum immediately, again. I already had experience with malfunctioning apple headphones (cable short-circuit) so I unplugged them, which helped. Then I noticed that the proximity to the cooktop had an effect. Apparently the induction pattern induced the same signal in the headphone cables that a volume down would produce...

    Anybody with a Bosch induction stove and an iPhone/iPod should try to confirm this.

  • by Mike Van Pelt ( 32582 ) on Friday October 29, 2010 @04:44PM (#34067748)

    Induction cooktops operate at a frequency of a few tens of kilohertz. Using it to excite a Tesla coil probably can't be made to work, at least, not with a reasonable number of turns on your secondary coil. The coil under the surface of the cooktop has a large number of turns.

    (To step up voltage, you want a few turns on the primary, and many times as many turns on the secondary.)

    • Re: (Score:3, Interesting)

      by Technician ( 215283 )

      Using the coil from a monitor flyback transformer with the powdered iron core removed, the secondary often will have it's voltage rating exceeded in a spectacular display. Be sure to use lots of ventilation.

      If you have several old dead monitors, you have a source of these.

    • Re: (Score:3, Informative)

      by Technician ( 215283 )

      A Tesla coil works by a very high primary pulse of current and then it ringing in a LC tank at the same frequency the resonant secondary is. Most inductive cooktops have no tuning to match the resonant frequency of the secondary. Most Tesla coils work on higher resonant frequency than the cooktops due to the nature of the secondary.

      One is a non resonant shorted turn and low impedance. The other is high Q and resonant over a very narrow frequency range. Outside of resonance, it is high impedance.

    • Maybe a laptop computer could be charged using half of the U-core of a monitor/TV flyback transformer and a high-speed diode bridge. The 3" waxed HV winding sits like a hockey puck directly on the cooktop's effective 5" surface, without the ferrite core half in between .
    • Re: (Score:3, Interesting)

      by Prune ( 557140 )
      This is why Tesla coils seem a lousy way to get high voltage. I've bought not-too-large 250 kV transformers from industrial portable X-ray machine power supply on eBay previously and you can chain a few together (in an oil tank, of course) to get in the megavolt range--at significantly higher _continuous_ power levels than with a Tesla coil of the same size. TCs are way oversized for what they accomplish.
  • sounds like something for the Mythbusters to check out!
  • by PolygamousRanchKid ( 1290638 ) on Friday October 29, 2010 @05:02PM (#34068002)

    My stove has levels that go up to 11. It's from Functionica. Whenever I get a visit from someone from the US, who has seen Spinal Tap, I show it to them and they laugh their asses off.

  • Use it to charge 30 Palm Pre's simultaneously. Or vice versa, buy 30 touchstone chargers and use them to cook a nice meal for that special lady in your life.
  • I've seen induction heating used to temper truck axles, among other things. Though I imagine that with minor tweaks you could make one hell of a HERF weapon out of one. Screw up all the cell towers within a few miles, etc. Check ebay for used resturaunt equipment.

    • Re: (Score:3, Interesting)

      by John Hasler ( 414242 )

      > ...with minor tweaks you could make one hell of a HERF weapon out of one...

      Not likely. These things operate at about 27KHz. On the other hand, you might be able to generate a couple of kilowatts of ultrasound by fabricating a "speaker cone" from a resonant metal disk and some magnets and use it to curdle your brain.

    • Re: (Score:3, Interesting)

      I've seen induction heating used to temper truck axles, among other things.

      I saw it used in the manufacture of commutators for starter motors:
      - Copper bar bent into circle.
      - Induction heat to orange in about 5 seconds, to weld the joint and take the stresses out of it. Result: Stress-free donut.
      - Smash the donut into shape (segmented hollow top-hat) with dies.
      - Mold plastic into it - to support it and make an insulated press-fit for the shaft).
      - Saw the segments apa

      • Hi ULR, I've been hanging out on the same board as you, under different nicks... (otherpower.com) as for your copper question, I think you'd be better off with conventional TIG welding due to the inert gas atmosphere - it's very difficult to work copper otherwise. Certainly TIG is much cheaper. Unless you plan mass-production enough to justify the cost of induction machines.

    • by sjames ( 1099 )

      I'm not sure about the magnetic field, but if the drive gets hot enough, it's wiped :-)

    • Re: (Score:3, Funny)

      by dangitman ( 862676 )

      Why would you need to? All hard drives have a self-wiping function if you wait long enough. With today's quality control standards, you usually don't have to wait very long.

      • by Tycho ( 11893 )

        Well, there is the Secure Erase ATA command present on all current hard drives, which is a full drive form and something the NIST considers more secure than the old DoD multiple pass overwrite procedure. Granted, just erasing or copying over the data once is 99.9999% of the time is going to make the previous data totally unrecoverable anyway. Although the effects of an induction range on the permanent, rare-earth, magnets from the voice coil motor that moves the heads might be fun. The metal plate those

  • Here is one experiment to try, how much can I fool around with an induction cooktop before I hurt myself?

  • Why are induction cooktops so expensive (here in NY)? I understand they're sold cheap in Asia. They don't seem to need to be very expensive.

    If they were cheap, they'd be worth using for energy efficiency. But they cost more than the energy savings.

  • Passports with IC chips in them can have the chips fried by a microwave oven, but it's hard to figure out how much to fry them without burning the passport itself.

    Can induction cooktops do it more precisely?

  • rig up a matching coil so that the magnetic field can be converted back to electricity and charge a battery powered device.

  • Someone should launch a youtube series called 'Will it Smelt?'

"My sense of purpose is gone! I have no idea who I AM!" "Oh, my God... You've.. You've turned him into a DEMOCRAT!" -- Doonesbury