To understand how the brain receives and sends signals to the body.
Until third grade, children tend to view organs of the body as individual parts. For example, the eyes are for seeing or the stomach digests food. At this level, students are ready to start viewing the body as one whole system. One way to ease into this view is to study systems within the body such as the digestive system, circulatory system, or the nervous system.
This lesson introduces the brain, but not just the brain. It emphasizes how the brain interacts with the rest of the body. Students will learn about this by understanding that "messages" go from parts of the body to the brain, and vice versa. At this age, it is less important for students to memorize scientific terms. This lesson focuses more on answering questions and helping students realize the "job" of the brain and the nervous system in regard to the body as a whole.
Note: Regarding the nervous system, fourth graders understand that the brain helps the rest of the body, but sometimes do not understand that the body also helps the brain. Fifth graders and grades below may have trouble understanding the role of the brain in controlling involuntary behavior. (Benchmarks for Science Literacy, p. 345.)
On this page is an activity that involves the "Stroop Effect," a brainteaser of sorts. There, students will find a list of words printed in different colors. Students will test themselves to see how quickly they can name the color of each word. The challenge is that the list is made up of color words, each of which has been written in another color. For instance, the word "red" is written in yellow text, so the students will have to say the word "yellow" while reading the word "red."
When students have completed this task, have them click on and do the Interactive Stroop Effect Experiment. If you want students to work in groups, print out the list of words with a color printer. Have groups of four get together and each member of the group take a turn reading the words as quickly as possible. Other members in the group can time that person.
Once students have completed the exercise, ask them these questions:
- If you could just look at blocks of color instead of words in color do you think you would be able to list the colors more quickly?
- Or, if you could just read the words in black and white and ignore color, do you think you could read the list more quickly?
- When you read the words aloud in the activity, how do you think your mouth knew how to say them?
- When you did the activity, what signals do you think your brain was getting?
- How do you think the signals were getting to your brain?
- Are there other ways to get signals to your brain?
These questions are intended to lead students to understanding that the brain gets signals from parts of the body, like the eyes, skin, and other senses. Also, that it sends signals to parts of the body. For instance, without the brain, the mouth would not know what to say or how to say it.
Have students use their Busy Brain student esheet to go to and read the short article entitled Pain and Why It Hurts. They should read just the first yellow box of text on the page. After the reading, ask students to name the five senses: hearing, seeing, tasting, smelling, and touch. Then discuss how the external parts of the body take things in and send "signals" to the brain.
Turn the discussion around and ask:
- What would happen if you couldn't feel pain?
- How does smell help you protect yourself? What about taste?
- Do you know anyone who is hearing or sight impaired? What other senses do they use to navigate their way through the world?
- Could you survive if you had none of the five senses?
- What does your brain do with the information it gets? (For instance, if you taste something bad, it tells you to spit the food out. If you hear a loud noise, it tells you to cover your ears, etc. Establish that the "signals" go both ways.)
As a class, brainstorm things that the brain helps the body do. Write these things on chart paper. Students will add to this list later.
Have students use their esheet to go to Probe the Brain from the PBS website. They should read that page then click on and do the activity. For about five minutes or so, let your students "probe."
Questions to ask:
- What did you notice as you were probing the brain? (Possible answers include: A part of the body twitched. When they probed on the right side, the twitch was on the left side and vice versa.)
- What were some of the body parts that twitched when your probed the brain? (Possible answers include: fingers, toes, ankles, knees, elbows, eyes, and so on.)
- What is the brain probe activity trying to tell you? (Accept any interpretations of this activity. In the next section of the lesson, students will gather information to help them focus their interpretation.)
Students should use their esheet again to read the Your Brain and Nervous System page from the KidsHealth website. They should then click the "Continue" button at the bottom of the page to read the next four pages.
After students have read these pages, ask them to think about the Brain Probe activity and refine their explanation of what it means.
At this point, have groups brainstorm for five or so minutes about as many things they can think of that the brain helps the body do. This will help you gauge whether your students are starting to understand the scope of what the brain does. They should come up with many more ideas than they did the first time. Allow students to share these ideas and add them to the class chart.
To check for student understanding of what they have learned so far, discuss this question:
- If you think of your body as a factory, and the brain is the boss, how does the boss communicate with the rest of the body?
Tell them to look for evidence to support the idea that the brain is the boss of the body and how it communicates with the rest of the body. Then, have them write a one-page description of how messages travel to the brain and how the brain is boss of the body. Students can write about one function, like breathing or walking and what the process is, or they can write in a more general sense.
Divide students into groups of four. Each group will create a diagram, role-play, model, or other original product to demonstrate the interaction between the brain and other parts of the body in one of these situations:
- You stub your toe.
- You hear a loud noise.
- You smell something delicious.
- You burn your finger.
- You are showering and the water suddenly turns hot.
- A soccer ball flies at your face.
The final products should demonstrate students' understanding of the concept that the brain receives signals from all parts of the body and sends signals to influence what parts of the body do. Have each group set up its demonstration and conduct it for the class.
Exploratorium has an online dissection of a sheep brain. The site also covers memory and the brain.
Why Do I Laugh or Cry? and Other Questions About the Nervous System, by Sharon Cromwell, introduces the nervous system in terms of reactions to experiences.