Energy in Food

A small piece of dry food is burned beneath a boiling tube containing water, and the rise in water temperature is measured. From this, the approximate energy released is calculated.

1. Measure 20 cm³ of water into a boiling tube and secure it in a clamp stand.
2. Record the initial temperature of the water with a thermometer.
3. Weigh a small piece of dry food (~1 cm³) using a balance and record its mass. Foods that can be tried include cheese, bread, biscuits, pasta, crisps (chips) and breakfast cereals.
4. Mount the food carefully on a wooden-handled needle (or hold with tongs if unsuitable for impaling).
5. Light the food with a Bunsen burner until it catches fire, then place it beneath the boiling tube.
6. Allow the food to burn completely, relighting if needed, and keep the flame under the tube to maximize heat transfer.
7. Stir the water gently with the thermometer and record the highest temperature reached.
8. Calculate the temperature rise and repeat with other food samples.

Investigating The Energy Content Of Food | Biology Practicals - Science with Hazel:

Energy in Foods Calorimetry Lab - Julian Buss:

📄 How much energy is there in food? - Practical Biology: https://practicalbiology.org/energy/energy-in-food/how-much-energy-is-there-in-food

• Dry certain foods (e.g., cheese cubes, marshmallows) beforehand to improve burning.
• Try different apparatus setups (e.g., soda can calorimeter, test tube vs. boiling tube).
• Compare class results to food labels, noting differences between experimental estimates and standard values.

• Eye protection must be worn at all times.
• Avoid nuts to prevent allergic reactions; check in advance for other food allergies.
• Handle mounted needles carefully to prevent puncture injuries.
• Take care with flames and hot equipment; provide first aid readiness for minor burns.
• Perform in a well-ventilated laboratory; fatty foods may produce smoky flames.
• Use only small food samples; never eat experimental materials.

• Why does the method only provide an approximate estimate of food energy content?
• How could the design be improved to capture more heat?
• How do the experimental results compare with nutritional information on packaging?
• What implications does food energy have for diet and health?