Introduction: Plant Biology - Root Soup

About: Teacher San Francisco

I am all about hands-on science. One of the best ways to engage students in their science education is by using food as a teaching tool. We finish our unit on plants with this extremely simple root soup project.  It ties directly to parts of the plant and health and nutrition. You can elaborate on this project to include calorie calculations and nutritional values if you want to incorporate more math into the lesson. You can also take the time to distinguish between roots, tubers, rhizomes, stems, etc - the gory details of plant biology.

I am surprised by how few of my students have ever cooked anything from scratch. The students are always surprised by how easy it is and how good it tastes. Many of them go home and make this soup for their families right away. Pretty cool!

Here are the ingredients: 1 medium leek, 1 medium carrot, 1 medium potato, 1 tablespoon olive oil (I forgot to include in  photograph-sorry), 1 large low-sodium bouillon cube (choose your favorite), 2 cups water, salt and pepper to taste.

Note: I like to try to find plants that are in their natural state as much as possible. I love the extra leaves, the snaggly root hairs and the dirt. You can really show the students more plant biology that way. The ones pictured here are pretty standard grocery store versions. 

CA Science Content Standards:
-Kindergarten: Life Sciences 2C Students know how to identify major structures of common plants and animals
-Grade One: Life Sciences 2e Students know roots are associated with the intake of water and soil nutrients and green leaves are associated with making food from sunlight
-Grade Two: Life Sciences 2d Students know there is variation among individuals of one kind within a population.
-Grade Three: Life Sciences 3a Students know plants and animals have structures that serve different functions in growth, survival, and reproduction
-Grade Four: Life Sciences 2a Students know plants are the primary source of matter and energy entering most food chains
-Grade Five: Life Sciences 2a Students know many multicellular organisms have specialized structures to support the transport of materials. 2f Students know plants use carbon dioxide and energy from sunlight to build molecules of sugar and release oxygen. 2g Students know plant and animal cells break down sugar to obtain energy, a process resulting in carbon dioxide and water.
-Grade 6: Ecology (Life Science) 5a Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
- Grade 7: Structure and Function in Living Systems 5a Students know plants and animals have levels of organization for structure and function, including cells, tissues, organs, organ systems, and the whole organism.
Grade 9 - 12: Biology/Life Sciences 1f Students know useable energy is captured from sunlight by chloroplasts and is stored through the synthesis of sugar from carbon dioxide. 1g Students know the role of the mitochondria in making stored chemical-bond energy available to cells by completing the breakdown of glucose to carbon dioxide.

CA Health Education Content Standards
- Kindergarten: Nutrition and Physical Activity 1.1N Name a variety of healthy foods and explain why they are necessary for good health.
- Grade 1: Essential Concepts 1.3 G Identify behaviors that promote healthy growth and development.
- Grade 2: Essential Concepts 1.4 N List the benefits of healthy eating.
- Grade 3: Practicing Health-Enhancing Behaviors 7.1G Determine behaviors that promote healthy growth and development.
- Grade 4: Essential Concepts 1.1N Identify and define key nutrients. Analyzing Influences 2.1.N Identify internal and external influences that affect food choices. Goal Setting 6.1.N Make a plan to choose healthy foods and beverages.  Practicing Health-Enhancing Behaviors 7.1.N Practice how to take personal responsibility for eating healthy foods.
-Grade 5: Essential Concepts 1.6.N Differentiate between more-nutritious and less-nutritious beverages and snacks. Analyzing Influences 2.1N Describe internal and external influences that affect food choices and physical activity. 2.2N recognize that family and cultural influences affect food choices. Decision Making 5.1.N Use a decision-making process to identify healthy food for meals and snacks. Goal Setting 6.1.N Monitor personal progress toward a nutritional goal.
- Grades 7 and 8: Essential Concepts 1.1.N Describe the short- and long-term impact of nutritional choices on health. 1.2.N Identify nutrients and their relationships to health. 1.4.N Describe how to keep food safe through proper food purchasing, preparation, and storage practices. 1.5.N Differentiate between diets that are health-promoting and diets linked to disease. 1.6.N Analyze the caloric and nutritional value of foods and beverages. Analyzing Influences 2.2.N Evaluate internal and external influences on food choices. Goal Setting 6.1.N Make a personal plan for improving one's nutrition and incorporating physical activity into daily routines. Practice Health-Enhancing Behaviors 7.1.n Make healthy food choices in a variety of settings. 7.2.N Explain proper food handling safety when preparing meals and snacks.
Grades 9-12: Essential Concepts: 1.2.N Research and discuss the practical use of current research-based guidelines for a nutritionally balanced diet. 1.3.N Explain the importance of variety and moderation in food selection and consumption. 1.4.N describe dietary guidelines, food groups, nutrients, and serving sizes for healthy eating habits. 1.5.N describe the relationship between poor eating habits and chronic diseases such as heart disease, obesity, cancer, diabetes, hypertension, and osteoporosis. 1.6.N Explain how to keep food safe through proper food purchasing, preparation, and storage practices, 1.8.N Describe the prevalence,causes, and long-term consequences of unhealthy eating. Analyzing Influences 2.1N Evaluate internal and external influences that affect food choices. 2.2.N Assess personal barriers to healthy eating and physical activity. 2.3.N Distinguish between facts and myths regarding nutrition practices, products, and physical performance. Decision Making 5.3.N Demonstrate how to use safe food handling procedures when preparing meals and snacks. Goal Setting 6.2.N Develop practical  solutions for removing barriers to healthy eating and physical activity. 6.3.N Create a personal nutrition and physical activity plan based on current guidelines. Practicing Health-Enhancing Behaviors 7.1.N Select healthy foods and beverages in a variety of settings. 7.2.N Critique one's personal diet for overall balance of key nutrients. 7.3.N Identify strategies for eating more fruits and vegetables. 7.4 N Describe how to take more personal responsibility for eating healthy foods.

Step 1: Clean the Plants

The first step is to clean and peel the plants. Take extra care to rinse in between the leek leaves.

You can discuss why there is so much sandy dirt in the leek. Students sometimes forget that the earth is required to grow their food.
You can talk about what else the leek needed to grow and do a review of photosynthesis here.

Step 2: Chop the Plant

Coarsely chop each plant part.

You can discuss safety in food preparation and handling.
You can ask what would happen if you kept chopping the pieces into smaller and smaller parts? What is the smallest part that would still be considered the plant? We have already looked at plant cells with microscopes so they should be able to connect the concepts here.

Step 3: Start Cooking

Put 1 tablespoon olive oil into a medium pot. Add the chopped leek and cook over medium heat until the leek is soft, approximately 10 minutes.

You can insert a quick chemistry lesson here. What is actually happening to the atoms and molecules when you cook something?

Step 4: Leek Is Ready

Softened leeks look like this.

Step 5: Add Everything Else (except Salt and Pepper)

Once the leek is soft, you can add the rest of the ingredients to the pot. Save the salt and pepper for the last step.

Again, you can insert some chemistry here: homologous, heterogeneous mixture? What happens to the atoms and molecules when you heat everything together?
You can also calculate how many calories are in the pot. What kinds of vitamins, minerals etc? You could make this very simple or very complicated depending on how you set it up and how accurate you want to be.

Step 6: Simmer, Simmer

Turn up the heat to get the soup to boiling. Then turn the heat down, cover the pot and let the soup simmer for 15 minutes or so until the potato and carrot chunks get soft. The soup should look like this when it is done.

Step 7: To Blend or Not to Blend?

Students can season the soup with salt and pepper at this point. I often bring in other herbs that they can experiment with. Some good ones are sage, thyme, rosemary, and dill. All parts of plants!  I have them put a bit of soup in a paper bowl and add a little bit of the herb to the bowl and taste. If they don't like it, they compost that sample and try another. Don't let them season the whole pot at once because they often ruin their samples by over-seasoning, which is actually a good thing for them to learn not to do.

I usually bring in my blender so students can puree samples of their soup in small batches. They are surprised to taste the difference when the soup is pureed and the flavors are blended. We also talk about texture and tongue sensations.

Ta da! You are done. The students are proud of their product.

More chemistry - homologous or heterogeneous mixture? What happens to the salt, NaCl, when you add it in?
You can calculate how many calories for each serving? How many servings of vegetables are in one bowl of soup?
You can integrate writing by having students create a "restaurant review-type" critique with lots of new food vocabulary provided. Or they can market their product with a brochure, which could include accurate nutritional information. The possibilities for integrated activities are endless.