BioEd Online

Teacher Background

All organisms that cannot trap and convert energy from the sun through photosynthesis must obtain the energy and other substances they need through food. Animals, fungi (mushrooms and their relatives) and many kinds of bacteria, for example, must eat plant parts, other animals or decaying plant or animal material. Living things that obtain energy from food are called consumers.

Not all animals have the same food requirements. People, for example, need to eat a variety of foods, including many different fruits and vegetables, to obtain all of the nutrients needed for growth and good health. 

Important components of food are listed below.

• Carbohydrates are the body’s main source of fuel. Starchy foods like breads, spaghetti, rice, potatoes, corn and cereals all are made up mostly of carbohydrates. Sugary foods like candy, jam and syrups also are carbohydrates. When possible, it is preferable to eat whole-grain breads and cereals, and to avoid sugary foods.

• Fats include butter, margarine, lard, shortening and cooking oil. Cheese, cream, chocolate, some meats and many desserts have a lot of fat. Fats are very concentrated sources of energy. Fats from animal sources, such as lard and butter, and fats that are solid at room temperature, generally are not as healthy as plant oils, such as olive, canola and nut oils.

• Proteins are important for the growth and repair of the body and muscles. Foods rich in protein include eggs, milk products, meat, dried beans, chicken, turkey and fish.

• Minerals are found in small amounts in food. They are needed for many body functions. Calcium, found in dairy products, is important for developing strong bones and teeth.  

• Vitamins are other chemicals found naturally in food and are needed in small quantities by the body. Vitamin A, for example, helps maintain normal vision and healthy skin. It can come from dark green, leafy vegetables, and yellow and orange vegetables and fruits.

Unlike other animals, people combine ingredients and/or cook them to make their food better tasting or easier to digest. 

Objectives and Standards

Concepts

• Different animals eat different kinds of food.

• Unlike other animals, people often cook their food or combine several foods together.

• Cooking helps make some kinds of food easier to eat and to digest.

Science Skills

• Observing

• Sorting and classifying

• Predicting

• Generalizing

• Measuring

Mathematics Skills

• Observing

• Measuring

Language Arts Skills

• Listening

• Communicating

• Writing

• Using descriptive language

• Following directions

Materials and Setup

Teacher Materials (see Setup)

• 50 raw popcorn kernels  

• Instant pudding, 3.2-oz pkg

• 1/2 cup of milk

• Clear plastic cup, 9 oz

• Cutting board

• Sharp knife

• Package of microwave popcorn, plain (see Setup)

• Plastic teaspoon

• Tablespoon

Materials per Group of Students

• 4 clear plastic cups, 9 oz

• 4 plastic teaspoons

• 2 cups of milk

• Instant pudding, 3.2-oz pkg

• Paper towels

• Plastic tray

• Tablespoon

Materials per Student

• Hand lens

• Copy of “My Science Journal” student sheet

Setup

1. Have students work in groups to complete activities. Assign a cooperative learning job to each student.

2. Part 1. Prepare the bag of microwave popcorn and allow it to cool. As an alternative, you may purchase a bag of prepared unflavored popcorn.

3. Part 2. Prepare a tray of materials for each group. Each tray will include four 8-oz plastic cups—each containing 1/2 cup of milk; an opened package of dry pudding mix (any flavor); one tablespoon; four plastic spoons; and paper towels.

Procedure and Extensions

Part 1. Popcorn observations

1. Before students begin handling food, make a point of demonstrating how to wash hands with soap and water. Have students wash their hands.

2. Prompt students to think about how they feel when they are hungry. Ask, Do you ever feel hungry? What do you do when you feel hungry? Discuss student responses.

3. Have students think about the types of food they eat. Help them identify the different kinds of foods available: breads and cereals; fruits; vegetables; milk and other dairy products; meats, fish, poultry and beans; fatty or oily foods; and sweets. Have students name examples of each kind of food. Ask, Do you eat this food raw? Why or why not?

4. Open the uncooked bag of popcorn. Give each student a hand lens and a few kernels of unpopped popcorn to observe. Have students use as many senses as possible to observe the corn. They will be able to smell, see (without and with the magnifier), hear (the kernel makes sound when dropped on a surface), touch and, if permitted, taste (by touching the tongue to a piece of the kernel). 

5. Direct students to write about or draw their observations in their a science journals.

6. Prompt students to consider why we need to cook some foods. Ask, Do we eat uncooked popcorn? Would you like to eat this for a meal or a snack? Why or why not? Ask students to predict what they think would happen if the popcorn was cooked.

7. Show students the prepared popcorn. Give each student a few pieces of the popcorn to observe. Again, have students use all of their senses to examine the new sample. Cut a kernel in half for them to observe. Have them record their observations as before. 

8. Ask the class, How did the popcorn change after it was cooked? Would you rather eat the uncooked or the cooked popcorn?

9. Help students understand that many foods must be cooked to make them easier to eat and digest. Ask students to think of other examples of foods that usually are cooked before they are eaten.

Part 2. Making pudding

1. Challenge students to think about how they eat different foods. Ask, Do you always eat plain bread or milk? Do you ever mix one or more kinds of food together to make something that tastes good? How about pudding? What do you think it contains? 

2. Explain that students will make pudding and then eat it.  

3. Remember to have students wash hands before touching food. Emphasize to students the importance of washing hands before handling food or eating.

4. Demonstrate to the class how to make the pudding. Measure two level tablespoons of pudding mix into 1/2 cup of milk. As you stir the mixture, advise the students to stir well, without sloshing, so that all of the dried mix is thoroughly combined with the milk. Show students how the mixture changed from a dry mixture in liquid to soft pudding.

5. Have Materials Scientists from each group pick up their tray of materials to make pudding. 

6. Each student should make his or her own pudding. Have students take turns using the tablespoon to measure the dry pudding mix from its container. After all students have made their pudding, give them time to eat their snacks.

7. Discuss the ingredients in the snack students have made. Ask, What did you mix together to make your snack? Did you end up with something that was different from the ingredients you started with? Can you think of any other foods that are made of mixtures?

Extensions

See lesson PDF.

Handouts and Downloads