Listener Martin wanted to know: "How long does it take the food I eat to become part of me?" Eva Higginbotham set off to find out the answer... Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

What happens to light's lost energy?

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...