Now and again, it's good to take a look at conventional wisdom through the eyes of a scientist. What proof is there to support the things we believe in, but rarely question?

To start the ball rolling, two doctors from Indiana University have trawled through scientific papers in search of support for six commonly held beliefs. Among those they tackle are: do hangover cures work; does sugar make kids hyperactive; do we lose most of our heat through our heads; and does eating at night make you fat?

All turn out to be modern myths, without a shred of evidence to support them. Writing in the British Medical Journal, the doctors involved, Rachel Vreeman and Aaron Carroll, point out that GPs are far from immune to believing things about our bodies that are simply untrue.

It's not the first time Vreeman and Carroll have questioned common beliefs. Last year, they discredited a clutch of other oft-repeated statements, including that our hair and fingernails continue to grow after death; that shaved hair grows back faster; that reading in dim light ruins your eyes; and that we only use 10 percent of our brains.

In the same spirit, I thought I'd see if we can gather our own list of mistaken conventional wisdom. Some obvious but nice ones: there's no gravity in space; chickens can live without a head (for a bit); and water spins the opposite way down a plughole in the southern hemisphere. Any more contenders?