SPECIFIC HEAT Purpose The purpose of this experiment is twofold: First to familiarize the student with the theory and practice of heat measurement; and second, to determine the specific heat of a solid. Theory Heat is energy that is being transferred between two bodies, solely due to their difference in temperature. For instance, heat flows from the sun to the earth because the sun is hotter than the earth. This type of heat flow consists of electromagnetic waves flowing through empty space and is known as radiation. When one stirs a hot liquid with a spoon, heat travels from the liquid through the spoon to one's hand, because the liquid is at a higher temperature than the hand. This type of heat transfer through matter but without a transfer of matter is known as conduction. Heat may also flow from a hot body to a colder body due to the flow of a gas or a liquid in a process known as convection. Energy that is flowing from a radio transmitting antenna to a radio receiving antenna could not properly be called heat energy, because the energy flow is not caused by a difference in temperature between the antennas. The addition of heat to a body may have a variety of effects -- as for example those that occur when food is cooked, or water is boiled, or a thermocouple generates electrical energy. But often, the only major effect of adding heat to a body is to increase its temperature. In this case, the heat added Q is related to the increase in temperature At and the mass m of the body by the following equation: Q - mc At (1) c is a constant of proportionality known as the specific heat. Values of the specific heat for various substances are listed in a number of handbooks of physics and chemistry. Since heat is a form of energy, it may be measured in terms of such ordinary units of energy as the erg and the joule. However, heat is often measured in units defined in terms of the ability of heat to cause an increase in temperature. One calorie is the amount of heat that must be added to one gram of water to raise its temperature by one Celsius degree. One BTU (British thermal unit) is the amount of heat that n added to one pound of water to raise its temperature by one Fahrenheit degree. It follows from these definitions and from equation (1) that the specific heat of water is I call(g.C') or 1 BTU/(1b.Fo), In this experiment we shall express all quantities of heat in calories, all masses in grams, all temperatures in degrees Celsius, and all specific heats in call(g.Co). The science of heat measurement is known as calorimetry. One of the more common procedures in calorimetry is known as the "method of mixtures." Basically, this procedure utilizes the principle of heat exchange. When a heat exchange takes place between two bodies initially at different temperatures, the quantity of heat lost by the warmer body is equal to that gained by the colder body, and some intermediate temperature is finally reached. This is true provided no heat is exchanged with the surroundings