I'm currently enjoying Tim Harford's three part series on Houdini on his Cautionary Tales podcast . Although best remembered as an escapologist, in the later part of his life, Harry Houdini included a section in his act that involved unmasking spirit mediums as fake. Earlier, Houdini had become friends with Arthur Conan Doyle, who became a fervent spiritualist and whose wife was a medium. Apparently, in one final attempt to persuade Doyle of the folly of his beliefs, Houdini did a demonstration for Doyle in his New York apartment. He hung a small blackboard from the ceiling out of reach, asked Doyle to to go out of the apartment and write a message on a piece of paper. When Doyle returned, Houdini got Doyle to stick a cork ball soaked in white ink on the board - to Doyle's amazement, the ball then wrote out his message (the Aramaic phrase Mene, mene, tekel, upharsin - mentioned in the Bible's book of Daniel) on the board. Houdini did this to demonstrate how the apparent...

Whenever the possibility of a trade deal between the UK and the US crops up, 'chlorinated' chicken comes back to menace us, much like Frankenstein's monster. But really it's a paper tiger. (This must surely be a mixed metaphor?) There is no doubt that there are potential dangers to such a deal for the UK, notably around food and medical supplies and services. However, when the press gets over-excited about chlorinated (or more properly chlorine-washed) chicken, it dilutes the whole argument, because this is absolutely fine. If you buy a bag of ready-to-eat salad in the UK it will have been chlorine-washed. This kills off the dodgy bacteria such as E. coli, Salmonella and Listeria that can easily be carried by salad leaves - the treatment makes it safer to eat. No one seems to panic about this. Now let's consider chicken. In the old days we used to be told to wash chicken before cooking it. We don't anymore because there is a real danger that doing so will splash...

Many decisions that a government takes have unwanted side effects. For example, while everyone surely thinks it's a good idea to stop people smoking, the government takes £6.50 plus 16.5% of the retail price from every packet of cigarettes: tobacco duties raise about £8.8 billion a year at the moment.  The response is often 'yes, but if we can get people off cigarettes it would reduce costs to the NHS'. It would - but only by an estimated £2.6 billion. So the exchequer would still be £6.2 billion a year worse off if we got everyone to stop. There is a similar issue with electric cars. At the moment, the fuel duty on petrol (gasoline) and diesel in the UK raises an eyewatering £28 billion annually. If we could wave a magic wand and switch everyone overnight to electric vehicles, that income would currently disappear. And though drivers might cheer, the government would certainly not be happy. So for some time there have been schemes afoot to recoup these potential losses. I ...

REVISIT SERIES -  An updated post from March 2015 Every now and then I get a semi-spam email (i.e. something I probably accidentally signed up to receive, but never really wanted) offering me the opportunity to buy cut-price 'treats', like a super car experience. I know some people love this kind of thing, but I just don't get it. I've got three problems with the whole 'super car experience' thing. But before that, I need to distinguish this from the early  Gerry Anderson series , which I loved as a boy. Here in the UK it was a black and white series, but it appears from the DVD that it was shot in colour. For primary school me, the best thing about it was that our Ford Anglia was excellent for playing Supercar, as the heater controls (the heater was an optional extra) made an excellent substitute for throttles, and it even had little fins on the tail, though they aren't visible in my picture below. However, I am not referring to Supercar , but rather an ...

Having recently revisited the Monty Hall problem, I thought it was worth also taking a look another, arguably even more mind-boggling probability problem that also got Marilyn vos Savant a lot of complaints when she included it in her column. The problem sounds trivial enough, and comes in the form of a statement for which we have to predict the probability. It reads ‘I have two children. One is a boy born on a Tuesday. What is the probability that I have two boys?’ It sounds trivial. The Tuesday bit is just window dressing, so we are looking at ‘I have two children, one a boy. What is the probability I have two boys?’ So with one child a boy, surely there is 50 per cent chance that the other child is a boy and a 50 per cent chance it’s a girl. Which makes the probability of having two boys 0.5, or 50 per cent. There’s a one in two chance.  But unfortunately that is not correct. The reason we get confused is that when trying to imagine the situation we think of the ‘first’ child w...

There's nothing the right-wing newspapers like more than a touch of wokeness-gone-mad - and back in February this was trumpeted by an article in the Daily Telegraph headlined Lego can be anti-LGBT says Science Museum (this is behind a paywall, but I was able to access it via Apple News). The story has since been picked up by many other news outlets. The outrage in the press is based on a self-guided tour called Seeing Things Queerly telling visitors that 'Like other connectors and fasteners, Lego bricks are often described in a gendered way. The top of the brick with sticking out pins is male, the bottom of the brick with holes to receive the pins is female, and the process of the two sides being put together is called mating. This is an example of applying heteronormative language to topics unrelated to gender, sex and reproduction. It illustrates how heteronormativity (the idea that heterosexuality and the male/female gender binary are the norm and everything that falls out...