Count The Errors, chemistry edition

There's a BBC News piece called "Whatever happened to kids' chemistry sets?", which makes the same point that many people have before, that zero-tolerance for any possible risk to children does not actually do those children any favours. It's hard to gain anything without at least exposing yourself to the possibility of pain; kids should be able to learn and have fun in ways that are at least a little dangerous.

You know the drill, though. Playgrounds, unsupervised play in general, chemistry sets; all neutered in the name of safety. For some reason many kids are still allowed to ride a bicycle, but heaven forfend you give your ten-year-old a pocket knife.

The video at the top of the BBC piece...

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...shows some experiments you can't do with modern kits. These experiments are as un-dangerous as they look.

The classic potassium-permanganate-plus-glycerol fire reaction (with some glucose added to provide additional fuel) does not have to be done in a fume hood. Just doing it outdoors and not deliberately inhaling the smoke will do.

You can still get the ingredients for that one quite easily, too. Glycerine and glucose powder are in many supermarkets, and potassium permanganate is still used as a disinfectant and general-purpose purifier of anything that benefits from being exposed to a moderately strong (by sane people's standards) oxidiser. So it's probably not illegal to send it through the post where you live (though there may be some ridiculous restriction having to do with drugs), and there are plenty of people selling it on eBay. (Check the Readily Available Chemicals lists, if you find yourself unable to locate some reagent or other. )

The only other old-chemistry-set "experiment" in the above video is even less alarming, simple flame tests. Again, salts that create brightly coloured flames or sparks aren't very hard to find; the one stop shop for them is a firework-supplies place, and you shouldn't need any fancy licenses or expensive special shipping to get them, since they're just the stuff that colours the fireworks, not the stuff that makes fireworks go bang. (And, again, Readily Available Chemicals can help.)

Oh, and that bit at the very end of the video with the squeaky test-tube sounds just like lighting hydrogen, which you can easily make electrolytically. But the tube seemed to be mouth-upwards, so it may have been some other flammable gas.

So the video's a bit boring, but OK. The actual BBC article, though, contains several mistakes.

The author says, for instance, "some chemistry sets of bygone ages even offered instructions and materials to be able to blow glass at high temperatures".

Well, yeah, of course they did. Making your own simple glassware - which pretty much only means bending and stretching tubes, not much in the way of actual "blowing" - is not particularly dangerous. You can do it on a kitchen gas stove if a proper burner is not available. Just stretching a glass tube lets you make very fine dropper nozzles; add some commercial flasks and beakers, some stoppers and a cork borer, and you can make a reasonably effective condenser, with a wet cloth and a fan standing in for the proper water jacket.

"Rosie Cook, assistant curator at the Chemical Heritage Foundation", is quoted as saying "You are letting a 12-year-old blow glass, there was uranium dust with a stereoscope where you could see the radiation waves..."

Bending glass tubes is not a task for toddlers, but any 12-year-old who cannot be trusted to do this is a 12-year-old who should also not be allowed to make themselves a sandwich. OK, the dangerous part of a bread knife is easier to tell from the safe part than is the case with glass (the First Law of the Laboratory: Hot glass looks exactly the same as cold glass), but this is no reason to presume that a 12-year-old has no more sense than a toddler.

And as for the "uranium dust" part... oh, man.

First, if any chemistry set ever came with actual uranium dust, I'll eat a whole shop full of hats. What chemistry sets came with was some bits of uranium ore or, at the very most, yellowcake.

And they didn't come with a "stereoscope"; you can't view ionising radiation with a View-Master. They came with a spinthariscope. (Perhaps the original piece as written had this right, but a sub-editor helpfully "corrected" it.)

That's a simulation, via Theo Gray, of what a spinthariscope looks like to a dark-adapted eye. (Actual video of the very dim twinkly lights tends to look rather underwhelming.)

And the "radiation waves" thing is a mess, too. I think you can see wave/particle gamma photons with some kinds of spinthariscope, but I'm pretty sure the chemistry-set ones - which you can still buy today - only respond to the alpha and maybe beta particles that decaying uranium and its daughter products emit on their way down the line to lead.

And then there's a neat-o little table at the middle of the BBC article, listing the interesting ingredients chemistry sets used to have and why they don't have them any more:

Chemistry sets of old

Chemical Why was it included? Dangers
Uranium dust It was "unofficially encouraged by the government", said chemistry set creator AC Gilbert, to help public understanding of
atomic energy
Radiation exposure is today strictly controlled due to wide range of
damaging health effects including risk of cancer
Potassium nitrate Combined with sulphur and charcoal to create gunpowder Can be used to make a fertiliser bomb
Lead acetate Used as a dyeing agent Toxic when eaten, as are many other lead compounds. Blamed for death of Pope Clement II in 1047
Ammonium carbonate Used in coloured fountain experiment where solution turned from red to blue The main component of some smelling salts, it can be dangerous if used in high doses regularly
Sodium hydroxide Used in colour-changing experiment Burns skin on contact

It says the intended purpose for potassium nitrate in chemistry sets was to make gunpowder, but it's not there any more because you can also use it to make a "fertiliser bomb":

Well, yeah, I suppose potassium nitrate could technically count as a fertiliser-bomb component, but I think they've actually confused it with ammonium nitrate. "Can be used to make gunpowder" would be a perfectly good thing to put in both the "original purpose" and "why it's no longer available" columns.

(I also love how the table lists one of the "dangers" of lead acetate as "Blamed for death of Pope Clement II in 1047". I don't think that fact actually played a major role in the thought process that led to the removal of lead salts from chemistry sets.)

And the only "why was it included" reason for sodium hydroxide was "used in colour-changing experiment".

That was it, huh? That's all it's good for? That's the sole purpose for a strong base? Makes you wonder why it was in there in the first place, doesn't it?!

It really does look as if nobody who had anything to do with the creation of the BBC article knew what they were talking about.

I found the BBC piece via this Boing Boing post by Maggie Koerth-Baker, which discusses the BBC article but does not dissect it. I suppose this proves the point; even Maggie, excited about science even by Boing Boing's standards, didn't notice the glaring errors. Perhaps I wouldn't have, either, if I hadn't spent a lot of childhood hours in the little workshop/laundry melting, boiling, reacting and distilling things.

And, of course, setting stuff on fire, more than once with the permanganate/glycerol reaction.

Among other things, I discovered that zinc burns with a pretty blue flame, and produces copious white fly-ash:

I never burned enough of it to get sick, though.

Making "plastic sulfur", a rubbery polymeric pseudo-allotrope that's the initial form of quenched molten sulfur, was also fun:

But smelly.

And yes, a kid can do this, in the kitchen, with very little chance of winding up dead:

(I'd also like to rehabilitate mercury's image. It seems almost nobody these days knows the difference between organomercury compounds - which are very very poisonous - and metallic mercury, which isn't good for you, but which is not actually very dangerous.)

I did the iron-and-sulfur reaction, too:

You can even get away with making nitrogen triiodide...

...if you make a respectfully minuscule amount, and wear eye protection. Which should be your habit when doing anything with chemicals or power tools, for the same reason that it's sensible to train yourself to use your indicators, by reflex, while driving. Yes, that does mean you'll occasionally feel silly because you indicated for, say, a turn in a road that isn't actually any kind of intersection. But it's better to indicate when you don't need to, and wear eye protection when reacting vinegar and baking soda, than to forget to indicate when it does matter or leave the goggles off when playing with explosives.

I didn't make thermite...

...until I was a grown-up, but I now champion that as an excellent experiment for kids, too.

Actually setting the thermite off definitely requires adult or responsible-teenager supervision, but the components of standard iron-oxide/aluminium thermite are quite inert and non-toxic (again, the kids should wear eye protection while mixing the ingredients, even though it isn't really needed), and the mixture won't light without a high-temperature fuse - a sparkler or magnesium ribbon. So small children can mix up thermite all by themselves, quite safely. And they should.

(One caveat: If they mix anything else into the thermite, especially water, then it will flash to vapour when the thermite burns and throw blazing thermite all over the place. This shouldn't matter unless you're setting the thermite off in an unsuitable location - q.v. - or standing unwisely close, though. You also don't need to panic about one drop of water or a couple of hairs in the thermite; it's not that touchy.)

If chemistry sets and, increasingly, schools no longer provide any real hands-on experience with chemistry, parents and kids themselves need to step up and do it, even if all you do is grow some crystals.

There's a lot of fun, and entertainment, to be had in the wide area between the kindergarten-science of dumbed-down chemistry sets and the truly hazardous experiments that, for instance, produce copious amounts of highly poisonous fumes, or have reaction products that are illegal to throw away.

Teaching kids that "chemicals" are dangerous is as stupid as teaching them that all drugs are equally, and enormously, bad. You let 'em ride a bike; you should also let 'em make some stinks and bangs.

7 Responses to “Count The Errors, chemistry edition”

  1. Bern Says:

    I managed to talk my high-school chemistry teacher into letting us make some thermite... :-)

    We didn't do anything else exciting, though. The closest we got was one of the chem teaches telling us about his previous job where he came across a large jar full of potassium in the store room - and that was one of the 'safer' materials he found.

  2. Patrick Duffy Says:

    Excellent article, Dan. Every year I deal with a fresh crop of students (mostly in their late teens) in a chemistry lab setting. I can tell you right now that the ones who pose the biggest threat to both themselves and others around them are the ones who are frightened due to a lack of prior exposure to chemicals and/or hazardous situations in general.

    We don't have to expose our kids to any/every kind of hazard there is, but stopping them from hurting themselves at all, and the concomitant instillation of fear that goes along with it, is actually worse for them in the long run.

  3. monomer Says:

    I had a job at my University dealing with recovering Zinc from waste slag from leftover from lead processing. Needless to say, every time I ran an experiment, I got the shakes for the next few hours. at the time I had no idea what it was, so I brought it up with my supervisor. He said that was to be expected since I was inhaling a fairly large dose of zinc fumes (and likely some lead as well) since my furnace couldn't fit under a fume hood, and that drinking milk would help.

    Anyways, I grabbed carton of milk from the nearest store, and the jitters went away almost immediately. My supervisor mentioned that it was the calcium, though I have since forgotten what it did.

    • dan Says:

      Milk is definitely a folk remedy for metal-fume fever, based on some sort of chelation-ish argument, but I don't think it actually has any effect beyond placebo.

      Since metal-fume fever is a self-limiting condition which, if you've only inhaled zinc vapour and not a big dose of heavy metals to go with it, does not seem to carry a risk of later horrible complications (cancer, brain damage, killing your liver or kidneys...), it's probably very amenable to placebo treatment. Milk isn't even a useful treatment for ingested poisons (well, possibly in some situation where water would do just as good a job), but you can find umpteen people recommending it for that purpose too.

      Here are some people discussing this.

  4. gwdonnelly Says:

    As a kid I loved playing with tools, fire, magnifying glasses, etc, etc. Along with some mates I made thermite and even had a go at some very small touch powder (could do with more practice at growing crystals there!)...

    Anyway, I would like to get my kids into doing experiments in a slightly more controlled, and safe, way - any recommendations on what to get a 4-5 year old started with?

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