1.3 Measuring energy content of food

Independent variable

type of food

Dependent variable

temperature/ °C

Controlled variable

mass of food/ water/ distance

Apparatus

• retort stand

• test tube

• tongs or mounted needle

• heatproof mat

• Bunsen burner

• thermometer

• goggles

• food samples

Method

1. Add 20cm³ of water to a boiling tube in a retort stand.

2. Record the starting temperature

3. Ignite 1g of food on a mounted needle

4. Hold burning food under the boiling tube until fully burned (relight if needed)

5. Record the final water temperature

Results

food with more energy causes larger increase in temperature

Improvements

• reduce heat loss using a calorimeter

• temperature sensor

• stir water to distribute heat evenly

Error

• entire food sample may not be burned

• energy lost to air/ to heat glass of boiling tube

Safety

• foods that can cause an allergic reaction

• safety flame when not in use