Frivolous Science

This may be old hat to those of you with rugrats in the house. You can make a non-Newtonian fluid with a starch suspension, such as a mixture of a little less than 2 parts cornstarch to one part water, a/k/a "oobleck" from the Dr. Seuss story. (If you can add a little fluorescent food coloring to it, so much the better in the oogliness department.) It becomes more viscous when subjected to pressure, which means, among other things, that you'll sink in it like quicksand unless you run over it quickly:


Put it on top of a speaker, and it will form writhing tendrils.


Useful information gleaned from comments sections: if your little brother puts it in your hair, just add some vegetable oil, and it will slither right off.

Wandering in random YouTube-association land, I found a new use for liquid nitrogen. When I was a kid hanging out with my dad at work, he used to get me out of his hair by giving me some to play with. He produced amusing effects by gargling it (just don't swallow). I wish I'd realized back then what it looked like when you poured it on top of water:


I think the kid was risking asphyxiation when he swam into the thick cloud.

For extra science fun, type in "Is it a good idea to microwave . . . " on YouTube.

14 comments:

  1. Cool.

    My daughter already is living in fear of the time when I teach my grandson how to make volcanoes on the kitchen table. And later, when he's older, how to make gun cotton in the kitchen sink.

    This oobleck stuff will be added to the lessons.

    On nitrogen asphyxiation, it's no worse than holding your breath, except if you tarry too long in the nitrogen (or CO2, come to that), you don't get to start breathing IAW your own wishes. But there are a few minutes before danger develops.

    As for the microwave, my then early grade school daughter, in combination with my innate laziness, discovered and enjoyed the Eggs that ate Las Cruces. The recipe is quite straightforward: beat up some eggs for the meal in a bowl, add seasonings to taste, heat in the microwave. In a bowl that seems much larger than necessary. Our eggs would puff up and nearly overflow the bowl, pulsating ominously as they expanded.

    Eric Hines

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  2. Anonymous2:57 PM

    For further entertainment, try "Will it blend?" Sometimes yes, sometimes no.

    LittleRed1

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  3. Fluid mechanics is the black hole of certainty. Does that sound Cassandrian?

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  4. The nitrogen would be dangerous in a pool for someone who'd been diving underwater and came up expecting to get a refreshing breath. It would smell and feel normal when you breathed it, but you wouldn't get any oxygen. If the swimmer got woozy, he could easily slip under the surface, with no one to see him in the fog.

    I worked on a wrongful death case of a guy who suffocated while cleaning a nitrogen-filled grain tank that way. He went down the top-hatch without a breathing tank or a watcher and probably never even realized he was in danger.

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  5. It's not really a good idea even to microwave food.

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  6. ...dangerous in a pool for someone who'd been diving underwater....

    I took your original remark in the context of the demonstration, where the pool seemed deliberately and carefully cleared before the nitrogen was dumped in.

    ...wrongful death case of a guy who suffocated while cleaning a nitrogen-filled grain tank that way. He went down the top-hatch without a breathing tank or a watcher....

    How did that work out to a wrongful death, unless the grain operator had no procedures or equipment for that? In the presence of such, it seems to me that the man brought his death on himself.

    Eric Hines

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  7. DL Sly7:34 AM

    I'm curious, Grim, what do you recommend using a microwave for if not food?

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  8. EH -- you may not have watched the pool demo to the end, but a guy dives in and swims through the fog for a bit, then swims underwater and comes up in the fog at the other end. Then the camera waves around to look at the fog, while I'm going, "Hey! Keep an eye on your swimmer!"

    The wrongful death case involved a non-English-speaking worker. Either he'd never been trained properly, or all the warnings were in a language he couldn't understand, I'm not sure. Somehow or other he didn't realize that it wasn't really air down in there, or that it needed more time to flush out after the hatch had opened. I was involved on the bankruptcy side, because their whole compartmentalized corporate system looked like one big alter ego. Anyway, we got the guy's family some money from one of the affiliates that hadn't been carefully emptied out.

    DL -- I suspect our host doesn't think microwaves ought to be used for anything! Not even drying the toy poodle.

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  9. you may not have watched the pool demo to the end....

    I watched all the way through. The boy dove into a known situation, creating a clearing in the gas, swam on the surface into the fog again, and then swam back out. Certainly, he bore watching as he entered (and reentered) the gas, but he was aware of the risks he was running. The more subtle risk strikes me as being the actual partial pressures of O2 and N2 in the clearing. The boy would have been well worth watching there, also.

    ...non-English-speaking worker. Either he'd never been trained properly, or all the warnings were in a language he couldn't understand....

    Sounds like a case of inadequate training and supervision, either way.

    Eric Hines

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  10. Sly,

    They make sense for reheating your lunch at the office, say. It's just going to come out in a worse condition than if you'd warmed it with a stove.

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  11. I'm not sure, but I suspect most of the cloud is frozen water vapor in relatively normal air.

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  12. Grim, you Luddite!

    The microwave is awesome, if used appropiatly. You go back to banging flint on steel without it.

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  13. And rheology is going to get even more insane soon - in microgravity, all bets are off.

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  14. DL Sly8:17 AM

    T99,
    If I can't nuke the poodle then I quit! There are only so many pleasures left, yanno...like all those experiments that Mythbusters tells you to never try at home.

    Grim,
    I agree that some foods such as pizza are not the same when reheated in the microwave, which is why I use a jet air oven. It's almost as fast as a microwave (5 min to make pizza too hot to pick up) with better results and you don't have to heat up the entire stove.

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