How the Brain Sees the Body
Grades: 7th-9th
Time: 1-2 hours
Objectives: Students will discover and learn how various parts of the body have greater
representation in the body and brain than others. Students will be introduced to the
nervous system's structure through measurement of its sensory capability which varies
in different sections of the body (i.e. how does the brain see the body). Additionally
students will discuss and consider the potential societal impacts that reverse
engineering the brain could have.
This lesson is intended to provide an opportunity for students to use the scientific
method to discover first-hand principles of how the nervous system and brain work. The
material involving the nervous system and organ system organization aligns well with
the National Academy of Engineering's Grand Challenge of reverse engineering the
brain.
Arizona 8th Grade Science Standards:
• S1C1: Observations, Questions, and Hypotheses (PO 1, 3)
• S1C2: Scientific Testing (PO 1,3,4,5)
• S1C3: Analysis and Conclusions (PO 1,2,3,5,8)
• S1C4: Communication (PO 3,5)
• S2C2: Nature of Scientific Knowledge (PO 1,2,4)
• S3C2: Science and Technology in Society (PO 2)
• S4C4: Diversity, Adaptation, and Behavior (PO 1)
Materials:
Toothpicks (about 1 per student)
Rulers (must show millimeters)
Procedures:
In this lab students will explore the sense of touch as experienced by our brain.
The lab starts with a question--how do our brains "see" our bodies? In other words, do
our brains pay more attention to certain parts of our bodies than others? Students
should try to answer this question to the best of their ability before starting the activity.
Another way to start the activity with more guidance is to ask students to draw a circle
graph (pie chart) of how much they think their brains feel touch from each of the
following groups: hands and feet, head, torso, arms and legs.
Place students in groups of 2 if possible. Have one student (Student A) close
his/her eyes while the other student (Student B) lightly touches either one or two
toothpick ends on the back of Student A's hand. Student A should try to tell if either 1 or
2 toothpicks is touching his/her hand. Student B should determine the largest distance
inside which it feels like there is only 1 toothpick touching when there are really 2. This
process should be repeated and the distance recorded for both students in the group
and at different locations around their body. Recommended locations are the finger tip,
back of the hand, cheek, shoulder, forearm, top of the foot, and lower leg.
Following the lab, ask the same question as before-- do our brains pay more
attention to certain parts of our bodies than others? Have students draw a new circle
graph and write a paragraph describing how they used their results to make the circle
graph.
Explanation and Post-lab:
The human brain tends to sense certain parts of our
bodies much more than others. In particular, a larger part
of our brain is dedicated to sensing finer details in how we
feel in our hands, feet, and mouth. This can be represented
in a drawing called a sensory homunculus (shown at right).
The body parts are scaled approximately relative to how
much the brain feels each part of the body.
Assessment for this activity can be based on the
detail and accuracy of students' notebooks. The
explanation of the revised circle graph based on data is a
great way to judge how well the student understands the
material and can connect
A good follow up activity based on this is coming up with a way you might make a
robot that can feel things like people do. Some other questions: What else could you
think of that could make robots more "human" besides feeling touch like we do? How
would you design a prosthetic arm if you could wire it directly into the brain?