The month is February 2017, I am almost 21 which is actually scary, I have almost finished my summer job on time which is actually scarier, and I have a tin of lithium-borate beads to make jewelry out of if I feel like it.
And the prompt for this month’s chain is Write about chocolate.
So Jewel put hers up early (early, cherub, you’re an amazingly organized person and I salute you), and I had a really good idea.
Why not blow up some chocolate? (Strictly speaking this is not an explosion, just a really, really fast burn.) I can then write about it, because science, because that’s what I do, and we will have simultaneously achieved the aims of a) scientific discovery b) writing this month’s post and c) allowing Jewel all the vicarious fun of blowing things up without having to actually do it and freak out her poor longsuffering sister and parents.
Experimental writeup in blatantly incorrect Science-ese follows. Videos of procedures provided under Observation. Jewel: if you try this at home I will not be held responsible for the consequences. Sarah: if your roommate tries this in the dorm I will not be held responsible for that either.
Someone I know was telling me about how to make model-rocket engines (carefully), and what they run on (sugar, and a powdered nitrate compound of your choosing, usually potassium.) And my wonderful brother was doing a mail-order science course last year, and because he’s not allowed to post the leftover chemicals back, I… now have a box of assorted chemicals. Including: sodium, barium, strontium, potassium, and calcium nitrates! Only two of which will work, but eh, life.
So I sat outside the other day and had a lovely time mixing nasty things in a spare teacup and setting light to them. With a long paper fuse. On an old brick nobody wanted anymore. But anyway, turns out you can set light to powdered sugar with this stuff, and it goes off with a most enchanting hiss and quite a lot of smoke. And it’s good fun.
So I thought why not do that with chocolate? The trouble was working out how much nitrate to use, so I went and asked the irresponsible rocketeer, and the general conclusion (we had a look at the ‘nutrition information’ on the chocolate wrapping) was that it’s kind of weird how dark chocolate has more carbohydrates than milk chocolate, but okay. Also protein would tend to burn slower than sugar, and fat would tend to burn faster, so on the whole it would average out and I could treat the whole chocolate bar as pure sugar for the sake of the experiment. This kind of blatant generalization isn’t too unusual in chemistry. Engineering yes, chemistry no.
Equipment and methods:
In the interests of making this scientific, I used three different kinds of chocolate, all from the same brand to reduce experimental variables.
- Whittaker’s Dark Ghana santé bar, 72% (presumably w/w but it’s hard to tell) cocoa mass. 51.0% carbohydrate (of which 33.3% sugars), 34.3% fat, 10.7% protein. Henceforth referred to as ‘dark chocolate’.
- Whittaker’s Dark Chunks bar, 50% cocoa mass. 61.4% carbohydrate (of which 52.1% sugars), 30.9% fat, 5.7% protein. Henceforth referred to as ‘semisweet chocolate’.
- Whittaker’s Creamy Milk slab, 33% cocoa mass. 51.8 % carbohydrate (of which 44.7% sugars), 35.6% fat, 9.2% protein. Henceforth referred to as ‘milk chocolate’.
Because this is ‘bucket chemistry’ as my friend so charmingly puts it, I wasn’t super-fussed about the exact quantities, and also in this experiment the nitrate is the limiting reagent by quite a long chalk, because I’ve got beggar-all of it compared to how easy it is to get chocolate. Strontium nitrate was disappointing in preliminary tests, and had a nasty tendency to put out my fuses, so even though I have lots of it, I can’t use the stuff. Resorted to sodium (already tested and found to be pretty good).
Chocolate was melted in a bain-marie (indoors, miraculously, because even my mother can’t see anything too risky about melting chocolate, plus, she was out) and the nitrate mixed into the warm chocolate. This slightly weird-looking mixture was poured onto greaseproof paper, and was left to harden.
You know you’re in a bad way when you have to label your own chocolate ‘Poison’ and ‘Not Poison’ respectively; the main hazard to this experiment was stopping people eating things they shouldn’t.
In the absence of a viable way of making touchpaper (I’m sure it’s great if you have unlimited potassium nitrate; I don’t) each sample was wrapped in a twist of plain paper, the very end of the twist dipped in kerosene (because my matches kept going out too soon otherwise) and lit that way.
Observation and Discussion:
1/2 tsp plain powdered sugar burned in 2:3 ratio with sodium nitrate, for control specimen. Note that this sugar contains 3% (w/w) tapioca starch, because manufacturers have no consideration for the consumer, but honestly I don’t care that it messes with the burn rate, it’s easier than using caster sugar.
1/2 tsp plain powdered sugar burned in 2:3 ratio with sodium nitrate, with a ground-up paper ash added for the sheer heck of it.
~2 g dark chocolate burned in 2:3 ration with sodium nitrate. (Yeah, I know it’s a weird ratio, I was going as high as I could with the nitrate I had.)
~2 g semisweet chocolate burned in 2:3 ration with sodium nitrate.
~2 g milk chocolate burned in 2:3 ration with sodium nitrate.
References: There are no references. To the best of my knowledge nobody else has been daft enough to try this.
n.b. if the videos aren’t working here, try it straight from YouTube.
So that was fun. Next month’s topic, for which I will be writing a post on March 13 and with which you may do what you like, is prompted by the realization that most of my regulars seem to write mostly prose: do you write in other formats (stageplay, screenplay, poetry, song, whatever) – if not, why not, and if so, why?
Thanks for reading.