Why does knocking your elbow unleash a distinctive "funny bone" jolt? Are we born with a sense of thirst? What are we seeing when we see things glow under ultraviolet? Why do our minds cling tightly to bad experiences? How do phones see the Northern Lights, even when we cannot? And do the planets in our solar system all move in the same direction? Dr Chris Smith and Clarence Ford have the answers... Like this podcast? Please help us by supporting the Naked Scientists