The Science Of Hot Food

Though it may seem like a virtually effortless and almost instant process, cooking your food actually involves some fairly complex physics. Here, we simplify the 3 ways that science really turns up the heat in the kitchen.

Conduction

Conduction—otherwise known as direct heat transfer—is the most straightforward form of cooking, so we'll start there. To begin, you'll need two basic things: a heat source, such as a burner on your stove, and a conductor, such as a frying pan, through which heat can be transferred. The key with conduction is direct contact. When a frying pan is placed directly onto an electric burner, heat is transferred from the hot coil to the surface of the pan. A closer look—and by close, we mean close enough to see the atoms of metal that make up the pan—will reveal that as more heat is transferred to the bottom of the pan, the molecules within the pan begin to vibrate. Allowed enough time, these molecular vibrations make your pan hot enough to similarly transfer heat to anything dropped in, such as butter—causing it to melt.

When it comes to common conductors, you've probably noticed that all of the pots and pans you use are made of metal, such as copper or stainless steel. That's because metal is one of nature's best conductors for heat, which means quicker and easier heat transfer from the stove to the your food.

Convection

When you cook food by way of conduction, you're really only heating it from one side—the bottom. Cooking by way of convection, on the other hand, allows you to cook your food from all sides at the same time. By heating the cooking media such as air (or water) surrounding the food, you can raise the temperature of what's cooking by raising the temperature of your medium. The best examples of convection cooking are boiling and baking; when you boil salted water to make pasta, the heat in the H2O molecules surround the food, allowing it to cook. In a similar manner, the air inside your oven acts as a heat source, surrounding your food. Because of this process, most ovens are equipped with fans to continuously and evenly circulate warm air while you bake.

Electromagnetic Radiation

Cooking with radiation may sound dangerous, but fear not—it's perfectly safe and natural. In principle, cooking with electromagnetic radiation involves heating food by bombarding it with waves of energy, such as heat or light. Upon hitting food, these waves cause the molecules within your steak or vegetables to absorb energy and ultimately increase in temperature. Sound like conduction? While they may seem similar, radiation requires no contact from the energy source and no conductor.

Though we can see only one type of electromagnetic radiation, known as the visible spectrum, there are many other forms of radiation that have proven useful for entertainment, for medical technology, and here, for cooking. Thanks to radiation, and a short-wavelength form of radio waves, we have microwaves. Another useful form of radiation in the kitchen and in the backyard—is infrared, used in toasters, broilers, and grills.