Why does my barbecue smoke follow me around?

The science of explosions, including what happens when brake fluid and hypochlorite mix, and what blew up in Beirut, why lemons make you grimace, the reason that the smoke from the barbecue mysteriously seems to know where you are standing, what determines your IQ, how a fruit battery works, why we forget dreams, and how genetics controls height. Join Dr Chris Smith and 567 CapeTalk's Kieno Kammies for the answers...