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:

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