BioEd Online

Teacher Background

Like all other forms of life, we humans must interact with our surroundings to obtain water and nutrients, protect ourselves from danger and reproduce. Our senses allow us to obtain the information we need for survival. Senses also work within our bodies to provide cues about the state of our internal organs and positions of our muscles and limbs.

Simple one-celled organisms, such as the amoeba, detect light, acidity, temperature and other characteristics of their environment over much of their external surfaces. More complex animals have evolved special cells, called receptors, which respond to specific aspects of the environment. Receptors translate information about the physical world and conditions inside the body into impulses that travel along nerve cells, or neurons. Most receptors are specialized to respond best to a particular kind of stimulus. For example, the simple nerve endings in the skin respond to pressure or temperature, while rods and cones, receptors in the back of the eye, react only to the presence of different kinds of light.

Specific regions within the brain receive and integrate information detected by sensory receptors. Through this process, we are able to interpret and react to the environment. Senses enable us to participate in the world—to learn, to achieve, to discover, to communicate. In this culminating activity, students use as many senses as possible to figure out what is inside “mystery” bags.

Objectives and Standards

Guiding Question

How do we use our senses to understand our surroundings? What types of input are provided by the different senses?

Concepts

• Senses work together to provide information about conditions inside and outside of the body.

• Sensory information is communicated to the brain, which interprets the signals detected by sense organs.

Materials and Setup

Teacher Materials (see Setup)

• 12 brown paper lunch bags

• 6 cups of plain, unsalted popcorn, popped and cooled

• 6 cups of plain, salted popcorn, popped and warmed (or freshly popped)

• Classroom human body diagram (see the activity, “The Brain: Protection”)

• Measuring cup

• Tape or stapler

Optional: Project “The Five Senses” page when reviewing the primary senses

Materials per Student

• Hand lens

• Science notebook

Setup

1. This activity will lead students to think about the basic scientific questions, “What do you think is happening?” and “How do you know?” Students will use as many senses as possible to figure out the contents of “mystery” bags” (two prepared bags per group of four students).

2. Label six paper lunch bags with the letter “A,” and six paper lunch bags with the letter “B.”

3. Prepare at least six cups of microwave popcorn. Place one cup of warm, salted popcorn in each of the six bags marked “A.” Previously popped popcorn can be warmed in a microwave for a few seconds.

4. In each of the six bags marked “B,” place one cup of cooled, unsalted popcorn. To keep students from peeking, tape or staple the bags closed.

5. Conduct the activity with students in groups of four.

Procedure and Extensions

1. Place one bag “A” and one bag “B” on the table or floor in front of each group of students. Direct students not to touch the bags or look inside until instructed to do so.

2. Ask, What do you think is in the mystery bags? Give students time to respond. Then, direct them to pick up each bag from the top and shake it gently. They should listen carefully to the sounds produced. Repeat the question, What do you think is in the mystery bags? Most students now will be able to determine that the bags contain small objects, and some may guess that the bags contain popcorn. Follow by asking, How did you know? Students should mention sound as a clue. Some also may have smelled the popcorn.

3. Have students smell the bags, still without opening them. Repeat the questions, What do you think is in the bag? Why? Students should mention that they used the sense of smell to identify the contents of one or both of the bags. If necessary, allow students to open the bags just enough to smell the contents.

4. Ask, What is different about the two bags? Let students touch the bags again. This time students should notice that one bag feels warmer. Ask, Which sense enabled you to notice the temperature difference between the bags? [touch, which includes pressure sensors and temperature receptors]

5. Now ask, Is either batch salted or flavored? Which sense or senses would allow you to determine this? [taste, smell and vision] Allow students to open the bags and remove some of the popcorn to observe with hand lenses. They may notice tiny salt crystals on some of the kernels. Have students draw and label the two kinds of popcorn in their notebooks.

6. Finally, allow students to confirm which batch is salted by sampling one kernel from each bag. Have them describe the flavors of each popcorn sample.

7. Conclude with a class discussion about how students were able to solve the popcorn mystery. Be sure to reinforce the concept that senses collect information from inside and outside the body and transmit it to the brain. Briefly review the primary senses that students have explored throughout this unit (vision, hearing, smell, taste, touch).

8. Ask students to identify all parts of the body and nervous system that they used in during this investigation (eyes, nose, mouth, tongue, ears, fingers, brain, neurons, etc.).

9. Stimulate further discussion by asking, How did the information get from your sense organs to your brain? [“sense organs” being eye, ear, fingers, nose, etc.] Students should be able to communicate that information, such as vibration from shaking the bag of popcorn, was detected by a sense organ and transmitted to the brain. The brain compiled and made sense of all information gathered during this investigation. Refer to different areas on the classroom human body diagram to summarize students’ ideas.

10. Have students revisit their notebook entries. Ask them to share what they have learned. Ask, Why is the brain important?

11. You may want to end the unit with a “popcorn” party.

Extension

Use additional flavors of popcorn in separate bags and have students make more observations. For instance, students can compare and contrast different kinds of popcorn in terms of appearance (color and shape), sound (while being shaken in a bag), aroma, flavor and temperature.

Handouts and Downloads

View or download the student storybook, Making Sense!