What happens if you urinate on an electric fence? We find out the answer to this and some of your other science questions on this week's Naked Scientists, including why chilli peppers are red, how does squinting help you see further and what's the best way to align your laundry with the wind? Plus, why blue food colouring could reduce the damage of spinal injury, how shrimps could catalyse biodiesel production and the physics behind the regularity of raindrops...