Thermograms are used to show where heat is. It would be used in certainprofessions, such as the army, dentistry, and especially used by doctors and in hospitals, as it can help to determine abnormalities. Breast thermograms are commonly used in hospitals, as they would display the abnormality of a tumour, if one were there.
There are different colours displayed, eg; white is the area with the most heat, followed by red. Green is the area with the least heat, NOT NO HEAT!!...thermograms only show areas which are heated. So even if the amount of heat were tiny, it would still be shown. However, do not make the mistake of putting in your essay, answer to question, etc., that green displays areas of no heat. THIS IS NOT TRUE.
Another factor, is that heat and temperature are different things. Also take this into account in your piece of writing.
I hope this helped you! :)