Energy in food (Edexcel GCSE Biology Combined Science): Revision Notes
📚 Revision Notes
Energy in food
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Food can be burnt to see energy it contains (calorimetry)
Calorimetry
The nutritional information on food packaging, such as the 10 calories per serving shown, is determined using a calorimeter. A calorimeter is a device used in the process of calorimetry, where small samples of material are burned to measure the energy they release.
Calorimeters are commonly used in the food industry to determine the energy content of food, and this energy is displayed in joules or calories on nutritional labels.
A basic calorimeter can be made by placing a beaker of water above a burning sample. The rise in the water's temperature provides a direct measure of the energy stored in the sample.
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Method
You need to find a food that will burn easily (best if dried)
- Weigh small amount of food & skewer it on mounted needle
- Add set volume of water to boiling tube to measure amount of energy transferred when food is burnt
- Measure temp of water then set fire to food – make sure Bunsen burner isn't near water or results will go wonky
- Hold burning food under the boiling tube till it goes out then relight the food & hold it under tube- do this till food wont catch fire again
- Measure temp of water again
- Then calculate energy using maths