Nervous System - Neuron Highway
Students will send a ''message'', a piece of paper attached to an unmodified paper clip, along a string to demonstrate how the nervous system work.
What You Need
Class sets consisting of:
- paper clips for attaching and sending messages written on paper
- string for attaching paper clips, and other objects
- tape for suspending strings by attaching them to other objects/surfaces
- paper for designing structures that help send ''messages'' along the string
- stop watch for timing students as they send messages across the string ''axon'' (optional)
Guide:
Attachments:
Safety Notes
Ensure you are familiar with Let's Talk Science's precautions with respect to safe outreach to youth.
What To Do
Introduce the topic of the nervous system / neurons by posing any of the following questions:
- What do you think of when I say the words ''nervous system''?
- What do you think the brain is made of?
- How might the brain send signals to the rest of your body?
Share the following information prior to the activity... If you do not require a refresher on the material, please skip ahead to the ''Activity Explanation'' section.
- The nervous system sends messages throughout the body through cells called neurons. Neurons are made up of different parts, with each part having a different function. see attached image
- Messages travel from cell body to cell body. Axons send signals out to other neurons. Dendrites receive signals from other neurons.
- Electrical impulses are used to send messages along an axon. The myelin sheath is a series of conductors that speed up the rate at which electrical impulses can travel. (For younger students, sections A - C will most likely contain a considerable amount of information. Section D is optional as it is not required for students to understand what is being simulated.)
- Once the message reaches the axon ending, it has to cross over a gap called a synapse before it can reach the dendrite of another neuron. The process of a message crossing a synapse is called an action potential.
After the needed material has been discussed, and once students are ready to move on, feel free to carry out the following activity:
*Before starting the activity, however, be sure to discuss with your host teacher as to where you could hang strings throughout the class. If possible try to suspend a string somewhere in advance so that you can demonstrate the activity to the class. Furthermore, have a slip of paper with a written message prepared in advance of demonstration.
Tip: As with any lesson, explain the activity first, then have students arranged into groups, and then hand out the necessary materials.
Activity Explanation:
Prior to demonstration, let students know that you will be simulating something that happens in the neuron. Ask them to think about what is being simulated while they watch.
Demonstrate the following to the whole class...
With a string suspended from end to end in the classroom, attach a paper clip with its original shape intact with a message also attached on one end of the string. Once it is attached, push it from end to end. Once the message has reached the end, read the message. Afterwards, ask them what process is being simulated... and if necessary guide them towards the idea that the message is an traveling along a string ''axon''.
Ask them, ''what could be done to make the message travel faster?'' Use student responses to introduce that we will be making paper airplanes* to help us guide our messages along our ''axons''.
*Paper airplanes can be attached to ''axons'' by taking a small ring of tape and, with the sticky section facing outwards, adhering it to the top of the plane, with the string, still suspended freely, resting in the middle of the ring of tape.
*If you are unsure how a paper airplane is made, please see the supplementary resources section.
Once the demonstration is complete, carry out the following general steps. Feel free to make modifications as necessary.
- Tell students that they will send messages along axons* suspended throughout the room. Let them know that they have two restrictions: the paper message has to stay attached to the paper clip during its entire journey, and the shape of the paper clip cannot be changed in any drastic way. *Feel free to also time them as they send their messages across the axon.
- Demonstrate how to create a paper airplane, or similar structure, if necessary.
- Have students write down a message they want to send along the axon. Provide paper if necessary.
- Have students create paper airplanes. (*During steps 3 and 4, suspend additional ''axons'' as needed if students finish building paper airplanes in advance of other students, ask them to assist their peers.)
- Have students test out which is more effective - the paper clip as is, or the airplanes that they have created.*
- Ask students what the faster of the two methods might be simulating... feel free to remind them what the myelin sheath is if need be.
Discovery
The paper structure that speeds up the rate at which the paper clip can travel acts much the myelin sheath in that it allows the message to reach its destination, or ''axon ending'', faster. In other words, if the paper clip -without being bent- were to travel along the string by itself, friction would reduce the speed at which the paper clip can travel, similar to how signals might travel through an axon if it did not have a myelin sheath.
For older students, rather than telling them to try using paper airplanes, ask them to try to come up with the fastest method, although it does not necessarily need to be a paper airplane, or paper at all for that matter, for moving messages across the axon. Have them also predict, observe, and record their findings as a means to get them to practice the processes of science.
What's Happening?
The paper structure that speeds up the rate at which the paper clip can travel acts much the myelin sheath in that it allows the message to reach its destination, or ''axon ending'', faster. In other words, if the paper clip -without being bent- were to travel along the string by itself, friction would reduce the speed at which the paper clip can travel, similar to how signals might travel through an axon if it did not have a myelin sheath.
Investigate Further
For older students, rather than telling them to try using paper airplanes, ask them to try to come up with the fastest method, although it does not necessarily need to be a paper airplane, or paper at all for that matter, for moving messages across the axon. Have them also predict, observe, and record their findings as a means to get them to practice the processes of science.
