Energy in food

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.

$$\text{Energy in Food (in J)} = \text{Mass of water (in g)} \times \text{Temperature change of water (in °C)} \times 4.2$$ $$\text{Energy per gram of food (in J/g)} = \frac{\text{Energy in food (in J)}}{\text{Mass of food (in g)}}$$ $$1cm^3 = 1g$$