1. In the bomb calorimeter used for the test the water is recondensed after it is vaporized In the bomb calorimeter we measure the HHV as the steam formed there is condensed. What I want to know is how the steam is re condensed? In the wikipedia it says In more recent calorimeter designs, the whole bomb, pressurized with excess pure oxygen (typically at 30atm) and containing a weighed mass of a sample (typically 1-1.5 g) and a small fixed amount of water (to saturate the internal atmosphere, thus ensuring that all water produced is liquid, and removing the need to include enthalpy of vaporization in calculations), is submerged under a known volume of water ... http://en.wikipedia.org/wiki/Calorimeter#Bomb_calorimeters If a small amount of water is admitted into the bomb then how it is condensing the steam? Also Bomb calorimeter is called a constant volume calorimeter, What does this constant volume mean? As the bomb calorimeter has to withstand high pressure so what does this constant volume refer to? Please help me with this.