Nerve Speed Relay

This demonstration measures how quickly nerves transmit signals in the human body by setting up a relay line of participants who respond in sequence. The activity illustrates the concept of reaction time and the speed of nerve impulses.

1. Arrange a group of participants standing side by side in a line or sitting in chairs.
2. Have each participant place one hand on the shoulder, knee, or arm of the person next to them.
3. Designate the first person in line to start the signal (for example, by squeezing the next person’s hand or tapping their shoulder).
4. Each person quickly passes the signal along the line as soon as they feel it.
5. The last person in the line raises their hand or calls out when they receive the signal.
6. Use a stopwatch to time how long the signal takes to travel through the line.
7. Divide the total distance by the total time to estimate the average speed of the nerve signal through the group (not the actual nerve speed, but a model of how signals move).

Connect the Neurons: A Classroom Activity - BrainU Videos:

• Compare times using different group sizes.
• Try different types of signals (hand squeeze, shoulder tap, word relay) and see which is fastest.
• Race two lines of participants to see which group relays the signal faster.
• Test if practice makes the group faster over multiple trials.

• Ensure participants do not hit or push too hard when passing the signal.
• Keep the demonstration in an open space to avoid tripping or bumping hazards.
• Remind participants to stay alert and focused on their turn to avoid delays.

• How does this model demonstrate the way nerves transmit information? (It shows how signals move from one “neuron” to the next in a chain.)
• Why is this slower than actual nerve impulses? (Real nerve impulses travel at up to 120 m/s, while human reactions add delay at each step.)
• What factors affect how quickly the signal moves down the line? (Attention, speed of response, number of people in the line.)
• How might repeated trials change the results? (Practice can improve reaction time, reducing delays.)