How to use a calorimeter?

Calorimeter is a heat measuring device. Many students use calorimeters in their science project experiments where they need to measure heat capacity or the specific heat of a substance. A calorimeter is generally used to measure the amount of heat energy and then uses that to calculate the specific heat of a substance or other heat related information.

Calorimeters include two vessels. One is known as an outer vessel and the other is known as an inner vessel. The air between the inner vessel and the outer vessel works as a heat insulator, so there is no or very little heat exchange between the contents of the inner vessel with the outside.  It also contains a thermometer and a stirrer. The thermometer is used to measure the temperature of the liquid (usually water) in the inner vessel. The stirrer is used to stir the liquid and distribute heat in the vessel. Calorimeters have a fiber ring that hold the inner vessel hanging in the center of the outer vessel. The fiber ring is made of insulating fiber material. Finally, each calorimeter has an insulating cover or lid with holes for the stirring rod and thermometer.

How to assemble your calorimeter? Start by assembling the vessels. Place the fiber ring in the larger vessel and then insert the small vessel in the center of the fiber ring. Insert the thermometer in the center hole of the lid or insulating cover; position it so that when you close the cover, the bulb of the thermometer will be in the center of the lower vessel, about one inch from the bottom. Insert the stirring rod and attach the handle of the insulating rod.

How to use your calorimeter to measure the specific heat of Iron?

Fill the inner vessel with 125 ml water. Close the lid and leave it for about 30 minutes. At this time the bulb of the thermometer must be in the water. (If it is not, push the thermometer lower). After 30 minutes, read and record the water temperature. 

Fill up a test tube half way with iron nails. Weigh and record the weight of the nails. Place the test tube with nails in hot-boiling water for about 10 minutes. This will allow the nails to get to 100ºC temperature without getting wet.

Open the lid of the calorimeter and transfer the nails to the inner vessel. Immediately close the lid. Move the stirrer up and down and read the temperature. Record the highest temperature. This will be the final temperature of the water and nails.

Calculate the temperature increase of water and temperature loss of iron nails.

Multiply the temperature increase of water by 125 ml of water to calculate the total heat transfer in calories.

Divide the total heat transfer by the temperature loss of iron; then divide the results by the weight of iron to calculate the specific heat of iron.