PTE Academic Speaking Retell Lecture: Bomb Calorimeter

PTE Academic exam questions are normally repetitive. There are some topics like bomb calorimeter, sound receptors, infinite monkey theorem and many more like these which appear very frequently in PTE Academic Speaking: Retell Lecture section. So English2language experts have done a bit of exercise on the bomb calorimeter retell lecture.

Related Link(s): PTE Retell Lecture Topics – Real Exam Questions

Most Repeated PTE Academic Speaking Retell Lecture: Bomb Calorimeter


Bomb calorimetry involves the ignition of the food in a metal container, the bomb, under a high pressure of oxygen (usually around 25 atmospheres). This results in the oxidation of the organic constituents to water and carbon dioxide along with oxides of the less abundant elements nitrogen, sulphur and phosphorus, and the consequent release of energy as heat. This heat is absorbed by water surrounding the bomb and the resulting increase in temperature of the water may then be used to estimate the energy value of the food.

Whilst bomb calorimetry is relatively fast, simple and precise, it suffers from the fact that it measures the energy of food constituents that may not be oxidized in the human body. Most of the dietary fibre constituents, for example, are not oxidized by the human digestive system and thus, for high fibre foods, bomb calorimetry gives a significant overestimate of the true energy value of the food. Additionally, the non-fibre constituents, normally regarded as digestive, may not be totally digested or absorbed by the human body.

Now you know what exactly is ‘Bomb Calorimeter’. As this topic appears very frequently in PTE Academic Speaking ‘Retell Lecture’, you can anticipate the topic well in advance in your PTE exam. You have to re-tell in your own the information in a 60-90 second lecture.

We advise you to start this re-tell lecture by making a note of important keywords and make maximum bullet points. Pay more attention on pronunciation and oral fluency. Also restrict the use of fillers such as hmmmmm, ohhhh.

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