Re: why is a bomb calorimeter better to than a calorimeter?

Date: Tue Mar 27 05:15:40 2001
Posted By: Samuel Silverstein, faculty, physics, Stockholm University
Area of science: General Biology
ID: 984746562.Gb

Message:

Zan,

Bomb calorimeters are very useful for measuring the total amount of heat that a material can give off when burned completely. For example, you might want to know exactly how much energy a certain fuel can produce, or the caloric content of some food. Bomb calorimeters can do this with much higher precision than simpler calorimeter designs.

The basic ideas behind bomb calorimetry are:

Supply oxygen to the sample to ensure it burns completely
Burn the sample quickly so that the heat produced has little time to diffuse into the surrounding environment before you measure the total change in the water temperature.
Enclose the reaction inside a STRONG chamber to contain the high pressure of the rapidly-burning sample. There is, after all, a reason it is called a bomb calorimeter!

I found this good lab exercise on bomb calorimetry on the web. It gives a good overview of the subject, and has some nice discussion of the finer points of bomb calorimetry that I haven't gone into.

Good luck!

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