DIRECTIONS: Introduced the lesson to the students with a review of heat transfer.
HEAT: Heat is the transfer of energy between objects at different temperatures. Energy moves from objects of higher temperatures to objects of lower temperatures. When two objects are left in contact for a while the heaat transfer will continue until both object's temperature reaches equlibrium.
Carbohydrated, proteins, and fats are major sources of energy for the body. The energy content of food can be found by burning a dry food sample in a colorimeter. A colorimeter is an instrument used to determine the specific heat capacity of a substance. When one object transfers thermal energy to anotheer object the energy lost by one object is gained by the other object. This is the principle on which a colorimeter works. Thermal energy is transferred from a known mass of a test substance to a known mass of another substance.
Heat is expressed in units called colories. A calorie (cal) is the amount of energy needed to raise one gram of water one degree Celsius. One calorie is equal to 4.184 Joules (J). The kilocalorie (kcal) is also used to express heat. One kilocalorie is equivalent to 1000 calories. The kilocalorie is also known as Calorie with a capital "C".
Carbohydrates and proteins provide 4 cal of energy/gram while fats provide 9 cal of energy/gram. Examine the food label on the boxes of various food products and you will notice that the calories are listed. In this experiment we will see if a single peanut produces enough energy to heat up a given amount of water and determine the exact amount of energy given off by the peanut.