What's an exponential dilemma? Why do copper bangles make your wrist go green? What causes hot flushes associated with menopause? Which is worse, viruses or bacteria? Why put power points at floor level? Can ketamine be used to treat mental illness? And why don't the bubbles from cracked joints cause an air embolism? Join Dr Chris and Kieno Kammies for the answers... Like this podcast? Please help us by supporting the Naked Scientists