We find out why petrol creates a rainbow effect when in contact with water, and how the behaviour of light can create all these colours. Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

Does same-sex attraction happen in animals too?

Each week we set out to solve one of the world's weirdest, wackiest, funniest and funkiest scientific puzzles. And along with the answer there's a brand new question to think about for next time...