LoCoEx/Vertebra
Water vortex
materials
2 plastic bottles - free of charge
connector ("Cyclone Tube", "Tornado Tube Connector") - € 3.10 or self-made - free of charge
Water - free
Instructions for preparation
Fill one of the two bottles to three quarters with water and connect it with the Cyclone Tube to the second bottle! Put a towel under for density problems!
execution
Rotate the water in the top bottle in a circular motion. This requires some practice. Watch!
A: Make a propper drawing of the vertebra! Or: Take a photo / video of the vortex
B: Explain the funnel shape based on the forces that act on a water particle on the funnel surface!
C:Task 1: Explain why a water particle m in a water vortex rotates the faster (i.e. higher orbital velocity v) the closer it is to the axis of rotation! This happens when it is sucked into the vertebra.
Task 2: Show: The surface forms a rotational hyperboloid! Tip: The inclination of the water surface (angle α) results from the sum of the forces of the centrifugal force and the weight of the volume.
Solution of Task 1 and 2: File:Wirbel in Wasserflasche engl..pdf
Classification
1. title: Water vortex
2. subject-matter: Mechanics - rotating systems - centripetal force - centrifugal force
3. price per set: € 3.10 for plastic connector ("Cyclone Tube")
4. atractivity: high, fascination!
5. recommended age of students: 11 years
6. time to perform the experiment: 5 minutes
7. time to prepare the experiment: 5 minutes
8. learning level: sec I, sec. II, upper
9. popularity: ?
10. standard - exotic: exotic
11. previous knowledge is required: depends
12. mathematization possible: yes
13. measurements can be performed: yes
14. media of presentation (photo/video...)
15. instructions and advices how to perform the experiment
16. didactic classification
17. learning objective control
18. theoretical background
19. occurrence in nature or/and technology
20. exercises for deepening the findings
