Experiment 2.32 Energy Content of Food

Recall how to carry out a simple experiment to determine the energy content in a food sample

Equipments:

Thermometer

Boiling Tube (filled with 20cm^3 of water)

Crucible --> measured mass of food sample 

Record initial temperature of water in Celsius, for example, 20C.

The food source is ignited and there is a heat transfer from the food source to the water. When the food is completely combusted, we then record the final temperature of the water, for example 30C. 

1 cm^3 of water has a mass of 1 g. 

1 cm ^3 of water, to raise its temperature by one degree takes 4.2 J. 

Calculation:

(mass of water (g) x temperature rise (C ) x 4.2)

Energy released from food per gram = ------------------------------------------------

mass of food sample (g)

= [20 x (30-20) x 4.2] / 10

= 84J / g