How do electrons orbit in atoms?

Where does the energy come from that keeps electrons in orbit within an atom? Can cars and truck weigh themselves like lifts to prevent overloading? How long do some atoms or molecules last in the body? What causes croup? Why would electrolysed water go green? Can viruses trigger asthma, and what is reflex sympathetic dystrophy? Join Dr Chris for the answers to this week's round up of questions as well as news that probiotic bacteria can alter brain chemistry - certainly food for thought!