Sinister caesium: the birth of a meme

As I discussed in my last blog post, the reactions of caesium and rubidium with water are not as impressive as people tend to think. But given the potential for hydrogen production is so limited compared to the lower mass metals, where did the idea that caesium reacts so dramatically come from?

Before video streaming over the internet became common, most people witnessing the reaction of caesium with water were likely to have done so only through a limited number of educational videos. Perhaps one of the most enduring of these was the Open University production Elements Organised: a Periodic Table, which is held up by many as the benchmark 'honest' reaction of caesium with water. In this video (displayed within the article), shown to a generation of school students, a small piece of caesium shatters the glass vessel in which it reacts – but many have failed to reproduce the effect.

I was able to speak to David Johnson, the writer and presenter of the original program and he agreed to examine some of the original archive footage and offer some insights.