Dancing After Death (Hainey)
Author:
Ryan Hainey
Principle(s) Illustrated
-Action Potentials
-Response to stimuli
Standards
Feedback mechanisms maintain a living system’s internal conditions within certain limits and mediate behaviors, allowing it to remain alive and functional even as external conditions change within some range. Feedback mechanisms can encourage (through positive feedback) or discourage (negative feedback) what is going on inside the living system. (HS-LS1-3)
Procedure:
1. Play video OR obtain a live squid, cut off its head, and pour soy sauce on its tentacles
Questioning Script
Prior knowledge & experience:
Students know from personal experience that living things respond to stimuli. Typically this response is the movement of muscles used to move towards or away from a stimulus. Non-living or dead organsims do not respond to stimuli........or do they?
Root question:
How and why does the dead squid move when exposed to soy sauce?
Target response:
Soy sauce contains high concentrations of sodium chloride (salt). When sodium interacts with the neurons of the dead squids tentacles an action potential is triggered causing the muscles to move. Even though the squid is dead neurons can still fire when exposed to sodium ions or electric impulses.
For advanced students: Why do the muscle contractions of the squids tentacles reduce in strength after multiple applications of soy sauce?
Common Misconceptions:
-Neurons require a brain to function
-Neurons require electric impulses to be stimulated
-'Death' occurs when the brain dies or is removed