# Energy Density of Foods

Theme:

Activity Overview: The simplest way to think about the relationship between energy and food is to recognize that food is a form of energy. Food stores chemical energy that bodies convert into kinetic energy to activate muscle power.

One way to evaluate foods and fuels is through the lens of energy density. Each different fossil fuel source has an average energy density, which is the amount of energy released when the source is burned. For example, gasoline contains about 44 megajoules per kilogram. Alternatively, oil shale contains about the same amount of energy as potatoes.

### Activity 1: Explore Energy Density

Project the following interactive component from Energy 101 in your classroom to explore the energy density of different foods. See how many kilograms of butter is required to achieve the same energy contained within one kilogram of wood, and more.

Pick a single baseline fossil fuel, such as anthracite coal or air-dried wood and test each of the different foods. Ask students to record the results of the investigation.

### Activity 2: Comparing Energy Density

Based on the results of the investigation in Activity 1, ask students to rank the different foods contained in this interactive element. Ask them to keep in mind that the more kilograms of food required, the less energy dense the food source. The energy sources ranked most energy dense to least energy dense are listed here.

1. Butter
2. Dark Cooking Chocolate
3. Lean Meats
4. Cereal Grains
5. Potatoes
6. Fruits
7. Vegetables

Chapter 31: Energy and Food from Energy 101: Energy Technology & Policy provides an introduction to the laws of thermodynamics and energy conversions. Access to Energy 101 for Texas students and teachers is provided for free by the State Energy Conservation Office as part of the Watt Watchers of Texas program.

TEKS

MATH.3.2D

Watt Watchers of Texas is a Partner Program of Smart Energy Education.