At the end of 2019, CLEAPSS revisited their special risk assessment for the reaction of
the screaming or howling jelly baby.
And this summer, my awesome lead technician Daniel brought me a present into school
which was some proper UK-style jelly babies, which are the sort of things that we need to be using for this reaction.
So now seems like a perfectly good time to make some sucrose suffer.
Although it's one of the first demonstrations I learned how to do
and is such a classic demonstration of the amount of energy stored just within one sweet,
or if you want to be pedantic, I guess sweet oxygen mixture, I hadn't actually done it in a while
because you definitely need to be using exactly the right kind of sweet to be able to do this demonstration safely.
Explosions have occurred where substitutions have been made for other types of sweet.
One of the possible culprits identified for this has been the citric acid or tartaric acid
that is required to make a sweet more 'sour' in taste.
And also there's a bit of a magical combination with the UK-style jelly baby.
There's a good level of moisture content in there to slow the reaction down a little bit
and that relatively low surface area just keeps things under control.
Don't ever be tempted just to throw in some powdered sugar as a substitution for this reaction.
So in short, always check out the most up-to-date risk assessment,
never deviate from the protocol, and always, always practise in advance.
I'm here working in a very well ventilated room. I have the windows wide open either side of me,
there are no smoke detectors here, and you'll notice I'm actually not using a fume cupboard for this reaction.
Fume cupboards will tend to be overwhelmed by the amount of smoke that's produced as we do this.
There have even been reports in the past of filtered fume cupboards catching fire
and even if that isn't going to be a problem for you, the chlorate that we're using here
will on contact damage glass and acrylic, so it's a great way of taking care of your equipment as well.
I have at least 2–3 metres of bench space set up at a 90 degree angle to the audience
and the bench has been protected by heat resistant mats.
Working on a middle bench means that I'm well away from windows, and especially paper displays on the walls.
There's loads of room all around me
and the audience is going to be 3–4 metres away and protected by a safety screen.
The tube that I'm going to be using today is good quality borosilicate glass
because otherwise the molten chlorate definitely will be damaging that
and is likely to break the glass, spilling molten chlorate everywhere
not something you want to happen.
Set your tube up at an angle, steep enough so that when you drop in the sweet it goes straight to the bottom.
Other accidents have taken place where people have used potassium chlorate which had suspected impurities in it,
so do make sure that whatever you're using is classified as reagent grade at least.
Weigh no more than 7 g of powder and put on a face shield before beginning to heat the tube
until the powder melts.
At this point, do not wait. Immediately, as soon as the powder has melted,
wearing heat resistant gloves, use a pair of tongs to drop in your victim.
Stand back and enjoy the show.
At the end of the reaction, make sure all of your surfaces are well wiped down.
And you'll need to dispose of the tube, even if it looks as if it can be washed up okay.
The glass will have been damaged by the molten chlorate and it won't be suitable for further use.
And the next time you're eating a sweet,
try not to think about all of the energy you'll need to burn off afterwards.
I think i need to go for a run.