Calorimetry is a method used to measure changes in enthaipy, or heat, that occur during chemical processes. Two common calorimeters are constantpressure calorimeters and constant-volume (or "bomb") calorimeters. Bomb calorimeters are used to measure combustion and other gas-producing reactions, In which the reaction is observed in a strong, sealed vossel. A simple constant-pressure calorimeter can be made from a foam colfee cup and a thermometer, in which energy changes in a resction are observed via the change in temperature of the tolution in the cup. The idea behind calorimeters is that if they aro sufficiently insulated from the outside environenent, any enerfy gained or lost in the chemical feaction will be directy observable as a temperature andror pressure change in the calorimeter