This week, how do painkillers locate the bits that hurt? Do they have an inflammatory sat-nav or do they just numb your entire body? Plus, we ask why potato peelers never need sharpening. Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

Why don't potato peelers need sharpening?

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...