Unripe pears are dry, yet ripe pears are juicy so how do they become moist? Philip Garsed put Dennis' question to plant scientist Sonja Dunbar, from Cambridge University... Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

How are robotic voices generated?

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...