When brushing one's dental equipment with an electric toothbrush one may notice a slight wobbling of the television images. Why does this happen? Plus, we ask why the Americas hadn't developed the same kinds of technologies as the Old World at the time of European contact. Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

Why didn't The Americas have what the Europeans had at the time of conquest?

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...