Brian+and+Jeremy

The goal of this experiment is to gain evidence to support the definition of the calorie (that a calorie is the amount of energy needed to increase the temperature of 1 gram of water by 1 degree celsius). We also plan to determine which foods release the most amount of chemical energy when burned. Our independent variable will be the amount of supposed calories in each food, and our dependent variable will be the increase in temperature experienced by the water. **Background** We will use this experiment to support the claim that the definition of a calorie is the amount of energy needed to increase the temperature of 1 gram of water by 1 degree celsius. For this purpose, we will use a homemade calorimeter to capture and measure the heat energy released by burning. The basic idea of a calorimeter is to capture the released heat energy with a reservoir of water, which has a high capacity for absorbing heat. The temperature of the water reservoir is measured at the beginning and at the end of the experiment. The increase in the temperature (in °C) times the mass of the water (in g) will give us the amount of energy captured by the calorimeter, in calories, represented by the equation: //Qwater// = //mcΔT// where:
 * Aim**
 * //Qwater// is the heat captured, in calories (cal);
 * //m// is the mass of the water, in grams (g);
 * //c// is the specific heat capacity of water, which is 1 cal/g°C (1 calorie per gram per degree Celsius); and
 * //ΔT// is the change in temperature (the final temperature of the water minus the initial temperature of the water), in degrees Celsius (°C).
 * Calorimetry**: Calorimetry is the measurement of the quantity of heat energy involved in processes such as chemical reactions, changes of state, and mixing of substances, or in the determination of heat capacities of substances. The unit of energy in the International System of Units is the joule. Another unit still being used is the calorie, defined as 4.184 joules.

**Materials and Equipment** To do this project, you will need the following materials and equipment:
 * homemade calorimeter, (for diagram and instructions on assembling, see Experimental Procedure, below) requires:
 * two tin cans, one larger than the other,
 * wood dowel, pencil or other rod-shaped support,
 * cork,
 * needle or wire,
 * various implements required to work with metal
 * graduated cylinder,
 * water,
 * thermometer,
 * safety glasses,
 * lighter or matches,
 * scale,
 * food items to test.

**Procedure**
 * [[image:http://www.sciencebuddies.org/mentoring/project_ideas/Chem_img016.gif caption="Homemade Calorimeter Diagram"]] ||
 * Diagram of Homemade Calorimeter ||
 * 1) Weigh each of the food items to be tested and record the weight.
 * 2) Fill the small can about half-way with a measured amount of distilled water.
 * 3) Measure the initial temperature (//Ti//) of the water.
 * 4) Set the food item on the needle.
 * 5) Place the cork on a non-flammable surface. Light the food item.
 * 6) When the food catches fire, immediately place the large can around the cork.
 * 7) Allow the food item to burn itself out.
 * 8) Measure the final temperature (//Tf//). Make sure the thermometer has reached a steady level before recording the value.
 * 9) When the burnt food item has cooled, carefully remove it from the needle and weigh the remains.
 * 10) Repeat these steps for all of the food items.


 * Data**

1/4 of one //CHOICE// cookie: Calories = 750 calories (or 0.75 kcal) Mass = 2.23 grams (normal) and 3.83 grams (soaked in Ethenol) Temperature (of water) = 61°C ---> 82°C

One //Blueberry Morning// cornflake: Calories = 278 calories Mass = 0.42 grams (normal) and 0.50 grams (soaked in Ethenol) Temperature (of water) = 22ºC ---> 23.5ºC