Gallium is solid at room temperature* but melts in your hand (melting point: 29.76°C or 85.57°F), and is available on Amazon for $1 per gram.
Some reviewers are suggesting that you also buy the gallium spoon mold so that you’ll have a really cool magic trick. But what’s the trick? Sure, you’d have a spoon that melts after a few moments of handling but what’s so magical about that?
It would have to be a pretty amazing trick for me to plunk down $120, and I’m just not seeing it.
Feel free to weigh in with any cautions you might know about - is it safe to handle liquid gallium? What happens when it melts in a bowl of warm water, or if somebody uses the Ga spoon to stir their coffee? Do the liquids combine in any way with the Ga, thus rendering it impure?
*YMMV - it would probably be liquid all the time here in Thailand.
You say “oh, you need a spoon to stir your coffee, here…ha ha it melted!!!1!”
That’s the trick. I don’t know anything about Gallium, so I’d probably do it while I was standing there and could stop them from drinking it, as opposed to just leaving it in the silverware drawer so it happens at some random point in the next few days.
You know that point in the video where he says “I know what you’re thinking; what happens if I try this with a full can”? That’s exactly what I was thinking.
I had a professor in Materials Science who brought a Melting Spoon into class and showed it meltying in hot coffee. He then poured off the coffee and poured the molten metal into a mold and cast a new piece.
The Melting Spoon typically uses a low temperature eutectic, though, such as Wood’s Metal, or one of the newer, low-T alloys, rather than pure Gallium.Here, for instance, is Theo Gray’s Mad Science page on the Melting Spoon:
Per Wikipedia, it appears to be relatively non-toxic, except for soluble gallium salts and only in higher amounts and not due to the metal itself.
On the other hand, some of the other materials commonly used, like the Wood’s metal suggested by CalMeacham, are highly toxic; Wood’s metal includes lead and cadmium (link includes a table of several other low-melting alloys, many of which have lead and/or cadmium, presumably there are others as well).
As an aside, galinstan (melting point -2°F) can be used in place of mercury if you want a non-toxic alternative to play with (it sounds expensive though; $199 for 50 grams from the first Google result, plus it tends to stick to things).
Galinstan is kinda hard to get, too. There’s a single supplier. When I wrote to him a while back in order to get a sample, he was out of it.
And I observed that there were other low temperature eutectics. Wood’s metal is pretty old. You can get newer ones, with lower melt points and lower toxicity:
Back in high school we made some Wood’s metal spoons and put them in the teachers’ lounge by the communal coffee pot. Then hung around at class break to see the reactions. I think it pretty much cemented the belief that lounge coffee was the worst liquid substance in the entire world. Later we recovered most of our metal from the coffee cups in the garbage can.
We didn’t give much thought to toxicity. It was, after all, high school.
