You can roast it or fry it, brine it or baste it, cook it whole or do it in pieces. There are dozens of ways to cook a turkey, and just as many opinions about which method produces the perfect poultry product. This Thanksgiving, it might help to consider science before you pick your main course recipe. Understanding the chemical reactions involved, experts say, can help you turn a pink, raw bird into a golden brown work of culinary art that fills the house with holiday aromas and fits your personal definition of perfection. What science will never do, however, is produce one answer that works for everyone.