Is static electricity down to positive or negative charges?

Why has everyone got a cold at the moment? How does an elemental diet treat inflammatory bowel disease? How does chlorine clean up drinking water? What is cholera? Can silver sterilise surfaces and water? Is static electricity down to positive or negative charge? What is reverse osmosis water filtering, and why is it controversial? Dr Chris Smith and Clarence Ford have the answers. Like this podcast? Please help us by supporting the Naked Scientists (thenakedscientists.com/donate)