Why does time speed up as we age?

Why does time seem to go by faster as we get older? What do IQ tests really measure? How do probiotic yoghurts work? We get the answers to all these on this week's show, as well as finding out why hair goes lighter in the sun and how 3D televisions work. Plus, is there such a thing as a 'good' virus? Like this podcast? Please help us by supporting the Naked Scientists