Why is salt needed in an old-fashioned ice-cream maker? Are gravity and electromagnetism the same, and could we build a big enough electromagnet to repel the Moon? Are some stars no longer where we see them? Does salt make water boil hotter and hence will my pasta cook quicker? Why do distant lights twinkle? How does an air conditioner work? Why do my ear-buds make me cough when I insert them? What causes my microwave oven to interfere with my WiFi and Bluetooth? Is it possible to re-magnetise the magnet on the bathroom cabinet? Can we use light to propel a spacecraft? And why do we find our... Like this podcast? Please help us by supporting the Naked Scientists