How does the structure of a fish influence how it moves in the water?
Learning Objectives
After completing this lesson, the student will be able to diagram, compare and contrast the relative contributions to thrust from pushing, pulling, or flapping forces in tuna, jellyfish and stingrays.
Standards
- NGSS-HS-PS2
- NGSS-HS-Life Science
- CCSS.Math.Practice.MP3
Supplies
- Paper to write on
Structure and Function
When a balloon is pulled through the air, the force of movement is generated from the front by dragging the string. When real animals move, their propulsion is generated typically from the back or side. Fish primarily generate forward force or ‘thrust’ by rhythmically moving tail fins back and forth. Manta rays flap their pectoral fins up and down (dorsoventrally), and jellyfish contract their bodies. These marine animals must generate a sufficient propulsive force, thrust, to overcome drag in order to move forward.
On the sketches of the tuna, manta ray and jellyfish below, indicate where the forces from pushing, pulling, or flapping, e.g. thrust, occur.
Next Steps
Next, do an experiment to see how water moves when a fish flaps its tail.
Last updated: November 23, 2022.
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