HOWTO make a disappearing prank gallium teaspoon

Disappearing Spoons sells kits to make your own gallium prank-teaspoons. Gallium spoons weigh nearly as much as stainless steel ones, and have a similar finish, but they dissolve in hot liquids like tea. When the tea cools, the gallium forms a lump in the cup, ready to be molded into a new prank-spoon!

Disappearing Spoons (via Make)


  1. Is gallium dangerous if accidentally ingested? Their website doesn’t seem to answer this question (even in the FAQ).

    One hopes not given the nature of this product.

  2. Um… What’s going to happen to a person who puts this prank spoon unknowingly in his coffee, doesn’t pay attention to it while it melts and then just drinks the coffee?

  3. So…if the pranked person happened to not notice the disappearing spoon and drank the liquid, what would be the effect on them?

  4. If he can’t tell that the weight of what he is holding is rapidly reducing, then he’s got bigger problems than drinking gallium.

  5. Potential Health Effects
    Causes eye irritation.
    Causes skin irritation. May be harmful if absorbed through the skin. The toxicological properties of this material have not been fully investigated. May cause contact dermatitis.
    May cause gastrointestinal irritation with nausea, vomiting and diarrhea. The toxicological properties of this substance have not been fully investigated. May be harmful if swallowed.
    Causes respiratory tract irritation. The toxicological properties of this substance have not been fully investigated. May be harmful if inhaled.
    May cause bone marrow abnormalities with damage to blood forming tissues. Administration of gallium to humans has caused metallic taste, skin rashes, and bone marrow depression.


    Just saying…

  6. Well, gallium hasn’t got an LD50 that I can find, and it’s a IIIA metal so it’s not going to be displacing any other elements your body uses. It’s staying molten at body temperature too, so it won’t form a solid lump in your stomach.

    Not that I’d bet my life on it, but I would guess the effect of drinking your spoon (and *there’s* a sentence I didn’t think I’d type when I got up this morning) would be mild nausea and a really interesting trip to the bathroom at some later point.

  7. Routes of Entry: Dermal contact. Eye contact. Inhalation. Ingestion.

    Toxicity to Animals:
    WARNING: THE LC50 VALUES HEREUNDER ARE ESTIMATED ON THE BASIS OF A 4-HOUR EXPOSURE. Acute toxicity of the vapor (LC50): 4786 ppm 4 hour(s) (Rat) (Calculated value for the mixture).

    Chronic Effects on Humans: The substance is toxic to lungs, mucous membranes.

    Other Toxic Effects on Humans: Hazardous in case of skin contact (corrosive, irritant, permeator), of ingestion, of inhalation.

    From the MSDS at

    I would definitely advise against drinking your spoon…

    1. The vapor pressure is on par with water, and that LC50 is not that small. You’d probably have to breathe in a substantial portion of the spoon’s volume in gallium to get anywhere near that, and the odds of that happening are not at all likely.

      This isn’t to say that I recommend drinking gallium; just that it’s really not as bad as you’re making it seem and that an inhalation exposure rating is not the appropriate measure to use here.

  8. One Spoon weights 14g, resulting in 18.7g Ga2O3(in case you burn the spoon) which has a LD50 of 10g/kg Bodymass.

    So about 700-800g – that are a lot of spoons.

    Drinking a spoon – crossing the metall detector at an airport would be not fun to explain later, or the x-ray.

  9. From your MSDS —
    Nitric acid, fuming

    Perhaps if you leave the “nitric acid, fuming” out of your drink, you might have a less dreadful outcome. The plain metal will be less soluble, and less of it absorbed, than the Gallium Nitrate.

    (Not that I’m recommending drinking your spoon; real results may vary)

  10. I found a Materials Safety Data Sheet for metallic Gallium,

    For short-term exposure, it mostly says “may cause irritation”, including contact dermatitis if you touch it, and points out that it hasn’t been fully investigated.

    For chronic exposure, it says that metallic taste, skin rashes, and bone-marrow depression have been observed.

    So, may be OK for a one-off, but think twice before adding this trick to the touring repertoire, I guess.

  11. When I was a kid, you could buy similar prank spoons from ads in the back of vaguely disreputable magazines. They were made of Wood’s metal, which has a melting point of 70 deg C. This seems more, uh, practical for the purpose than Gallium. With a melting point of 30 deg C, a gallium spoon could melt before your very eyes on a hot summer day.

  12. I wouldn’t want to risk any practical joke that has the potential of somebody drinking the molten gallium, just in case.

    A much better practical joke is “I have here a very concentrated acid… observe as I destroy this spoon…. and now, using the power of my mind, I will put my hand in the acid.”

  13. Melts, not dissolves. It changes physical state from solid to liquid, it does not become dispersed and suspended within a solution.

  14. IIRC, long ago gallium compounds were investigated as a substitute for highly toxic tetra-ethyl lead as a knock inhibitor in motor fuels. The people exposed to it developed a persistent, strong and distinct odor of garlic about their persons.

  15. Wood’s metal (50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium) is the traditional one for this prank, I think, but considering that it is toxic it’s not really a good choice. Field’s metal (32.5% bismuth, 51% indium, 16.5% tin) is less toxic.

  16. FAR cooler is if you feel the crystals form in the melt as it cools.

    Also, gallium cries when you bend it. Or was that indium?

  17. This would be cool: have a container partitioned into a top part with hot water and a bottom part with ice water. A hole in the top part would let the liquid gallium flow through into the ice water.

    Put a little mold under there and you could melt a spoon to make a shiny statue of a LOLcat.

  18. Dissolves? Not. You can see its molten self sitting at the bottom of the cup.
    I suppose the description is trying to cancel out all those people who go out in the rain and say, “I’m not sugar; I won’t melt,” perhaps?

  19. is this a Make Fail? You know what is cooler than a fake melting teaspoon, fake cool silver contact lenses.

  20. OMG – THANK YOU for this.

    I have been wanting to play with some gallium for years now. The spoon trick is awesome.

  21. check the MSDS for Sodium Chlorine (table salt!) says you should avoid skin contact, if it’s accidently ingested medical advice should be sought immediately, it’s causes cancer, and there’s a special note about the adverse effects on the human reproductive organs. We’re talking about table salt! I’ve been working with gallium for a long time.. some view it as a 21st century trace element, it works as an anti bacterial agent, and it’s even injected in the bloodstream for something called a Gallium scan.

  22. Since the melting point is 86 degrees, I think the subject of the prank might notice the handle of the spoon melting as they or you pick it up… I think the prank scenario is about as realistic as the old ads in the back of comic books.

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