Watch the video first to find out a bit about this challenge — the 6th in the eight-challenge series.
Oxidation of sugar is the source of energy for most animals. Those that live around hydrothermal vents deep in the oceans are one of the exceptions!
The challenge for the Brawns and Beauties this time was to create three mixtures of the ingredients each not to exceed 8 grams.
The assessment criterium — which they came up with — was the following:
(Sugar mass – mass of final product) × duration of the flame × height of the flame.
(The only condition I had laid down when I asked them to decide on it, had been that it couldn’t be the same as for the Gunpowder Challenge: The Explosive Meet.)
So, on the one hand, the higher the proportion of the initiator (potassium chlorate)
- the smaller mass of sugar
- the higher rate of reaction and possibly more efficient the reaction (to a point), so shorter the duration of the flame
- the smaller the mass of final product and
- the taller flame
But on the other hand, smaller the proportion of the initiator
- the bigger the mass of the sugar,
- the lower rate of the reaction and possibly lower the efficiency of the reaction, so longer the duration of the flame
- the bigger the mass of the final product and
- the smaller the size of the flame
The challenge therefore was to decide on the optimum ratio of the two to get the highest product of the three figures!
The rate of reaction of course would also depend on the form of the two reactants. Obviously, finely powdered initiator AND sugar would be more efficient than any other combination.
Of course I had every single “firing” of the mixture filmed. But I can’t find them. 🙁 I am sure I filmed them because we have the results of the tests.
However, I did a similar challenge/investigation with the 10th graders! Here’s their result just to give you some idea for how it might turn out.
(If you are interested in another idea for how this could be investigated/used in the classroom, click here.)
In this challenge, both the Brawns and the Beauties scored points but equal points!