Do you feel tired, irritable and bored during the week? Yet full of beans and enthusiasm at the weekend? We find out why this could be! Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

What is fire and how does it burn?

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...