Tekla Perry writes: We cook our food today using technology invented to bake bricks. We can do a lot better. Nathan Myhrvold explains what's wrong with today's ovens and challenges oven designers make them better. He says, "Oven designers could do a lot to make ovens heat more evenly by taking advantage of the different ways ovens transfer heat at different cooking temperatures. At 200 C or below, convection moves most of the heat. But at 400 C, radiant energy starts doing a fair amount of the heat transfer. At 800 C, radiation overwhelms convection. Why couldn't we have an oven designed to cook primarily by convection at low temperatures that switches to radiant heating for high-temperature baking? ... The shiny skin of raw fish reflects heat, but as the skin browns, it reflects less and less energy. That’s why food under a broiler can seem to cook slowly at first and then burn in the blink of an eye. But technology offers a fix here, too. Oven designers could put optical sensors in the oven chamber to sense the reflectivity of the food, and then the oven controller could adjust the heat automatically or at least alert the cook as the surface browns. And a camera in the oven could feed to a color display on the front panel, giving the chef a clearer view of the food than a small window in the door can. Indeed, a decent optics system could allow designers to dispense with the glass in the door altogether, reducing the gap between the hottest and coolest corners of the oven and obviating the need to open the door and rotate the food midway through cooking.