IB Biology Food Energy Content Experiment Essay

IB Biology Food Energy Content Experiment - Essay Example 263). The nutritive value of food is derived from the ability of a food to supply energy to the organism (McDonald et al. 263). To calculate the quantity of chemical energy present in food, it is necessary to convert it into heat energy and calculate the amount of heat it produces (McDonald et al. 264). This conversion is conducted by oxidizing the food by burning it; the amount of heat that is created from the complete oxidation of the unit weight of food is identified as the gross energy (McDonald et al. 264). The central determinant of the gross energy content of a food is its degree of oxidation as conveyed in the ratio of carbon plus hydrogen to oxygen (McDonald et al. 264). Carbohydrates contain approximately the same gross energy content of 17.5 MJ/kg DM while triglyceride fats contain lower amounts of oxygen and have a higher energy content of approximately 39 MJ/kg DM (McDonald et al. 264). Proteins have a higher level of gross energy values than carbohydrates due to the fact that they contain the oxidizeable element nitrogen (McDonald et al. 264). The present study was conducted in order to determine the energy content of four different samples of food that includes a cracker, a Mars chocolate bar, bread, and a 'Flips' chip. The researcher hypothesized that the mass of food will have no effect upon its energy content. In addition to this, it is hypothesized that the food with the highest energy content is the 'Flips' chip followed by the bread, cracker, and Mars chocolate sample. The researcher determined the energy content of the food by calculating the amount of Joules per mass in grams of each sample. Method: The researcher chose four different food samples to test for energy content. The quantities of food included a 2-gram sample of cracker, a 5.6-gram sample of Mars chocolate, a 10.4-gram sample of bread, and a 0.8-gram sample of a 'Flips' chip. There were three variables in this experiment. The first variable was the variety of food type, the second variable was the temperature of the water, and the third variable was the difference of mass of each sample of food. All other factors of the experiment were be consistent including the distance of the bunson burner from the test tube, the volume of water in each test, and the environment in which the experiment was conducted. The researcher used a beaker to measure 25cm^3 of water into each test tube. Five tests of each food were conducted in order to determine a mean value of each sample. The mass of each food sample was determined as well as the temperature of the water in each test tube before heating. Each food sample was attached to a pin and burned with a bunson burner. When the food sample burned, it was placed under the test tube until the flame burned out. During this time, the water in the test tube was stirred in order to evenly distribute heat transfer from the flame. After the flame burned out, the Celsius temperature of the water in the test tube was measured. The mass in grams of the food sample was then measured. The following formula was used in order to calculate the amount of energy each food sample contained in Joules: 25g * temperature rise of water (C) * 4.2 (J/g/C)/ mass of food (g)= Energy (J/g) This process was repeated for each food sample Results: Food Mass (g) Volume of water (cm3) Temperature after heating (oC) Temperature before heating (oC) Rise in water Temperature (oC) Energy content of food (J/g) Cracker 2 25 34 20 14 735 Mars