Why can we only recycle some types of plastic?

Do women suffer from flatulence, and what affects your level of flatulence? Does hitting someone on the head actually knock them out? Is being a psychopath down to nature or nurture? Why does the weather stay warm when the seasons shift? Why can we only recycle some types of plastic? Can a swollen heart be reduced in size? Can nuclear rods power spaceships? Can mattresses and pillows reduce snoring? Dr Chris Smith and Clarence Ford have all the answers... Like this podcast? Please help us by supporting the Naked Scientists