Untestable theories (and hairy phones)

If you were to say that your phone has a fringe then people would probably think you'd bought a wig for your phone, as an IB physics student/teacher you may think otherwise. I guess light fringes are so called because they are often parallel lines like a hair fringe but that maybe nothing to do with it. In class yesterday (1st day of classes) we were going through a bit of what we did at the end of last term. Talking about the first use of fuels I asked the class why, after the discovery of fire, did humans start to cook food. There were many theories but most thought that a cave man had stumbled across a burnt dead animal and tasted it, discovered it tasted better than raw meat and decided to cook food from that day on. I'm not sure that an animal burnt in a forest fire will taste that good but its an untestable theory so take it or leave it. After experiencing a raw steak in a cheap Paris restaurant, my theory is that the cave people had bad teeth and the cold raw meat hurt their teeth as they chewed it. To alleviate the suffering they warmed the meat on the fire and discovered that this not not only made it warmer but also changed the texture making it easier to chew. Anyone who has cooked cheap steak will spot the flaw in this argument but these cave dwellers dined only on the best. How anyone dicovered that crushed grass seeds could be mixed with water and baked to make bread is an even bigger mystery. Anyway, the phone fringes are quite nice.