Rounding out my amateur mad-scientist routine, I bought 100 grams of Gallium to mess around with.
I've read the WP page and am as informed as that makes an amateur such as myself. The stuff has a couple of interesting properties that have created a couple of questions, both general and specific, and I hope here to impose on the wisdom of the far-more-well-informed-than-me forumati as follows:
1) Of course, the cool thing about Gallium is that it melts at about 85 degrees. My Gallium, alas, came pre-melted in its little tube. It does not re-freeze at 80 degrees, nor at whatever temperature my home freezer maintains. I have read that it "supercools," which I get, but do not understand how to go about "seeding" it to induce crystallization or at least freezing. I've tried dropping in a shaving of dried - "frozen" gallium from the side of the bottling, but no luck. First, am I understanding the concept of "seeding" correctly? Second, what can a homebound fool like myself do to get this stuff to freeze?
2) Gallium "wets" both plastic and glass, leaving a silvered-trail inside of each vessel I've tried to move it to. WP suggests that it does not wet polyethelyne, but the #2 bottle I had around got wet just the same. I'm wasting xx amount of the stuff every time I transfer it from one vessel to another. How is this stuff kept? It's got industrial uses that require it to be blended in exact amounts with other things, so surely "eh, a little stuck in the test tube is no problem" isn't the answer.
3) The foregoing led to the maths question - as I squandered the substance, pouring it from one sized (and composed) tube to another, I began to wonder, assuming its wetting properties, if I "wasted" more in a narrow, tall test tube or a broad, short one. Or in the long flat bottom of a mason jar. Basically, the question I found myself pondering is the degree to which the surface area (which in this context I mean the part of the substance touching the vessel, not the actual "surface" exposed to the air - so, maybe, the "contact" area) of a given substance changes depending on the shape of the vessel it's in. My thought process (such as it is) went as follows:
- No, the contact area stays the same. A wider test tube has a broader base, and vice-versa. Same amount of stuff, same amount of contact area.
- No wait, that can't be right. If I, say, studded a test tube with rubber dots all over the inside, they'd create a lot more contact area than they would cause the substance to creep up the side of the tube. If I dented a malleable vessel inward, I'd be creating MORE contact area on the inside than there was before. I think.
- OK, so assuming this to be the case, what's the ideal shape for a vessel to minimize loss, that is, what shape produces the LEAST contact area per volume of stuff contained therein? Probably a perfectly spherical one, or some sort of oblate one, for reasons that feel intuitive but are beyond my ability to reckon with words, much less formulae.
Finally, any safety concerns beyond the obvious? I've not been touching it directly, and already know it not to poison you in the fashion of mercury (hence its appeal), but can I freely hold it in my hand? Can I let my middle-schooler freely hold it in his hand? How hard to we have to scrub our hands afterwards?
I know it reacts with some other metals, but is it the sort of thing where I need to be REALLY careful not to let it come into contact with, say, copper?
Look, I already observe best amateur mad scientist practices (the fools at the academy! I'll show them!), but while heeding warning labels I still value the real-world insights of anyone who knows more about this stuff than I do, which is every actual chemist everywhere.
So, there you have it. Anyone who feels like schooling the noob (and I'll take all the maths and vocabulary corrections you care to offer), I would be obliged for the benefit of your experience and insight on any of the above.
- Ian
I've read the WP page and am as informed as that makes an amateur such as myself. The stuff has a couple of interesting properties that have created a couple of questions, both general and specific, and I hope here to impose on the wisdom of the far-more-well-informed-than-me forumati as follows:
1) Of course, the cool thing about Gallium is that it melts at about 85 degrees. My Gallium, alas, came pre-melted in its little tube. It does not re-freeze at 80 degrees, nor at whatever temperature my home freezer maintains. I have read that it "supercools," which I get, but do not understand how to go about "seeding" it to induce crystallization or at least freezing. I've tried dropping in a shaving of dried - "frozen" gallium from the side of the bottling, but no luck. First, am I understanding the concept of "seeding" correctly? Second, what can a homebound fool like myself do to get this stuff to freeze?
2) Gallium "wets" both plastic and glass, leaving a silvered-trail inside of each vessel I've tried to move it to. WP suggests that it does not wet polyethelyne, but the #2 bottle I had around got wet just the same. I'm wasting xx amount of the stuff every time I transfer it from one vessel to another. How is this stuff kept? It's got industrial uses that require it to be blended in exact amounts with other things, so surely "eh, a little stuck in the test tube is no problem" isn't the answer.
3) The foregoing led to the maths question - as I squandered the substance, pouring it from one sized (and composed) tube to another, I began to wonder, assuming its wetting properties, if I "wasted" more in a narrow, tall test tube or a broad, short one. Or in the long flat bottom of a mason jar. Basically, the question I found myself pondering is the degree to which the surface area (which in this context I mean the part of the substance touching the vessel, not the actual "surface" exposed to the air - so, maybe, the "contact" area) of a given substance changes depending on the shape of the vessel it's in. My thought process (such as it is) went as follows:
- No, the contact area stays the same. A wider test tube has a broader base, and vice-versa. Same amount of stuff, same amount of contact area.
- No wait, that can't be right. If I, say, studded a test tube with rubber dots all over the inside, they'd create a lot more contact area than they would cause the substance to creep up the side of the tube. If I dented a malleable vessel inward, I'd be creating MORE contact area on the inside than there was before. I think.
- OK, so assuming this to be the case, what's the ideal shape for a vessel to minimize loss, that is, what shape produces the LEAST contact area per volume of stuff contained therein? Probably a perfectly spherical one, or some sort of oblate one, for reasons that feel intuitive but are beyond my ability to reckon with words, much less formulae.
Finally, any safety concerns beyond the obvious? I've not been touching it directly, and already know it not to poison you in the fashion of mercury (hence its appeal), but can I freely hold it in my hand? Can I let my middle-schooler freely hold it in his hand? How hard to we have to scrub our hands afterwards?
I know it reacts with some other metals, but is it the sort of thing where I need to be REALLY careful not to let it come into contact with, say, copper?
Look, I already observe best amateur mad scientist practices (the fools at the academy! I'll show them!), but while heeding warning labels I still value the real-world insights of anyone who knows more about this stuff than I do, which is every actual chemist everywhere.
So, there you have it. Anyone who feels like schooling the noob (and I'll take all the maths and vocabulary corrections you care to offer), I would be obliged for the benefit of your experience and insight on any of the above.
- Ian
via JREF Forum http://forums.randi.org/showthread.php?t=271064&goto=newpost
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