Cannon fire

Ethanol is one of the first organic compounds students are exposed to. They may be expected to learn about its structure and methods of producing it. Many modern specifications require that they understand the benefits and drawbacks of using it as an alternative fuel.

In this column last year I described how bottle rockets could be used to show an ethanol-air mixture driving a ‘vehicle’,¹ but I often keep that demonstration for lessons on complete and incomplete combustion. When it comes to lessons studying ethanol itself, I like to have another demonstration to hand and one of the most impressive is the Cannon Fire experiment.

I normally use this demonstration purely for enthusing. It’s one of the few demonstrations I do that regularly receives a round of spontaneous applause from the students, perhaps because of the surprise factor. Although I wouldn’t normally use this demonstration while teaching reaction rates, it is worth noting how particle size plays a big role in this demonstration.

With an accompanying video, Declan Fleming discusses how to produce the Cannon Fire experiment, from setting up the demonstration to conducting the experiment and class discussion afterward.