Energy Content of Foods

Introduction

Energy content is an important property of food. The energy your body needs for running, talking, and thinking comes from the food you eat. Energy content is the amount of heat produced by the burning of 1 gram of a substance, and is measured in joules per gram (J/g).

You can determine energy content by burning a portion of food and capturing the heat released to a known mass of water in a calorimeter. If you measure the initial and final temperatures, the energy released can be calculated using the equation

where H = heat energy absorbed (in J), Δt = change in temperature (in °C), m = mass (in g), and C_p = specific heat capacity (4.18 J/g°C for water). Dividing the resulting energy value by grams of food burned gives the energy content (in J/g).

Objectives

In this experiment, you will

• Measure temperature.
• Analyze data.
• Use a balance.
• Determine energy content.
• Compare the energy content of different foods.