What could be more important to our lives than food?

Food Chemistry is a 16-lesson unit, designed for fourth-graders and successfully field-tested with both fourth- and fifth-graders, in which students investigate basic nutrients found in the foods they eat. Through a series of physical and chemical tests, students discover which nutrients--starches, glucose, fats, and proteins--are found in common foods. Through reading selections they also learn more about the role these nutrients play in human health and how these nutrients are related to the growth and development of their bodies. And they learn about vitamins and the fascinating history of their discovery.

Repeatedly throughout this unit, students have opportunities to gather, organize, and interpret data. They also discover that applying scientific techniques can provide them with useful information about nutrients and foods. Through predictions, discussions, and comparing results from tests, students become engaged in a science process that encourages problem solving and fosters the concept that in science, results frequently cannot be reported with "yes-or-no" answers.

Lesson 1 begins with a brainstorming session in which students share what they know about foods and what they would like to learn. In Lesson 2, students receive and set up the laboratory equipment. They also examine the foods they will be testing and practice lab techniques that help avoid contamination. After examining the class set of eight foods, each group of students decides on two other foods they will bring from home to test.

The starch test in Lessons 3, 4, and 5 introduces the testing cycle that extends through Lesson 14: first, testing five known liquids (water, corn oil, corn syrup, milk, and corn starch solution) to observe positive and negative test results; then, testing foods to identify the presence or absence of a specific nutrient; and finally, pooling class results and reading about that nutrient and its role in our health. Students repeat this cycle for each of the other nutrients in the unit: glucose, fats, and proteins.

In Lessons 6, 7, and 8, students use Tes-Tape® to test for glucose, and they are challenged to create their own charts or tables for recording and organizing their data. The glucose test also introduces students to the concept that chemical tests are not always clearly positive or negative. They learn to interpret results that indicate varying amounts of a nutrient.

The fat test in Lessons 9, 10, and 11 uses unglazed brown paper, presenting students with the concept that some nutrient tests are simpler than others. In Lessons 12, 13, and 14, students use Coomassie blue to test for protein. This test is more complicated than the others, requiring two steps and a developing solution. It also introduces a type of test in which the absence of change indicates the presence of the nutrient.

In Lesson 15, students examine food labels and discover that labels supply useful information about the nutrients in foods. And they read about another important nutrient--vitamins. Finally, Lesson 16 challenges students to use all the testing techniques they have learned to analyze the nutritional components of a marshmallow.

This is an exciting unit for students. They get to work with food, "do" chemistry, and gain some insight into a subject that is a part of their everyday lives. Don't be surprised if some of the questions students ask go beyond what you know or can find out. The subject is complex, there is still much research to be done on human nutrition, and people have differing opinions about what is "good" and "bad" in nutrition. No one can provide all the answers. What we can do is help students learn how to continue to find out for themselves.