Measuring energy in food

The energy in a sample of food can be measured by burning it and using the energy released to heat a known volume of water.

Equipment

  • Bunsen burner
  • Heat proof mat
  • Boiling tube
  • Clamp stand
  • Thermometer
  • Measuring cylinder
  • Mounted needle
  • Food samples

Method

  1. Pour 20 ml of water into the boiling tube.
  2. Place the tube in a clamp stand.
  3. Measure and record the mass of the water.
  4. Measure the mass of the food sample.
  5. Fix the food onto the end of the needle and set light to it.
  6. Hold the burning food sample close to the base of the boiling tube.
  7. When the flame goes out measure and record the temperature of the water.



The energy in different foods can be compared using the temperature change per g. Just divide the temperature change by the mass of food used. The equation below can be used to find the energy in each food sample.

The mass of water is 20g if you used 20ml.
Foods to Try

Most types of breakfast cereal work well, corn flakes, Frosties etc. pasta is good, and peanuts work really well.

Risk Assessment

Long hair must be tied back, take care when skewering the food samples place the sample on a hard surface first, (not your hand). Avoid using peanuts if anyone in the room has a nut allergy.

Hint: It is easier to skewer the food samples if you gently heat the needle first.

 

 

 

 

 

 

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