Why should you cook at different temperatures in fan ovens?

Dr Chris takes on the final batch of questions of 2024 on CapeTalk. Why does sound cause me pain? What’s the difference between white and brown vinegar? Does radioactivity harm inorganic matter? Is there a cure for anosmia (inability to smell)?What’s outside our universe? Do we pass out on rollercoasters? How can we recognise our own baby’s cry so well?