Remember my post last week about Brainiac dropping caesium in water? I reposted my concerns to a mailing list of people who do science demonstrations, make museum exhibits, and so on, and we had a jolly little argument about whether it was plausible or not. We went roughly fifty-fifty, I think.
Then the chap who did it posted. Turns out, dropping 10g caesium in a bath of water does very little indeed, and (two years later!) they did indeed blow the heck out of a bath with stage explosives. What you see in that film is entirely faked.