{"id":1914,"date":"2024-06-20T11:53:14","date_gmt":"2024-06-20T09:54:04","guid":{"rendered":"https:\/\/experiments.school\/?post_type=product&p=1914"},"modified":"2024-06-20T11:54:05","modified_gmt":"2024-06-20T09:54:05","slug":"097-bottle-tornado","status":"publish","type":"product","link":"https:\/\/experiments.school\/en\/product\/097-bottle-tornado\/","title":{"rendered":"097 – Bottle Tornado"},"content":{"rendered":"","protected":false},"excerpt":{"rendered":"

Water vortex\u00a0\u00a0<\/strong><\/h2>\n

Bathtub swirl<\/strong><\/h2>\n

\u00a0<\/span><\/p>\n

Introduction to:\u00a0<\/span>\u00a0<\/span><\/h2>\n
    \n
  • Vortex<\/span><\/li>\n
  • Rotational hyperboloid<\/span><\/li>\n
  • Centrifugal force\/centripetal force<\/span><\/li>\n
  • Conservation of angular momentum<\/span><\/li>\n
  • Vortex funnel <\/span>\u00a0<\/span><\/li>\n<\/ul>\n[video width=\"1920\" height=\"1080\" mp4=\"https:\/\/experiments.school\/wp-content\/uploads\/2024\/06\/097-video2-end.mp4\"][\/video]\n

    https:\/\/experiments.school\/wp-content\/uploads\/2024\/06\/097-video1-end-2.mp4<\/p>\n

    Material:\u00a0<\/span>\u00a0<\/span><\/h2>\n
      \n
    • 2 plastic bottles (= PET bottles, recommendation: volume 1.5 liters, absolutely transparent!)\u00a0\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Hard plastic connector, commercially available\u00a0<\/span><\/li>\n<\/ul>\n

      Or <\/span><\/b>\u00a0<\/span><\/p>\n

        \n
      • 2 lids\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Hot glue with gun\u00a0<\/span><\/li>\n
      • Sandpaper<\/li>\n
      • Scissors\u00a0\u00a0<\/span><\/li>\n<\/ul>\n

        \u00a0<\/span>Instructions:<\/span>\u00a0<\/span><\/h2>\n
          \n
        • Take the finished connector\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

          Or<\/strong> make one yourself:\u00a0<\/span>\u00a0<\/span><\/p>\n

            \n
          • Roughen the surface of the two lids with sandpaper and glue them together\u00a0<\/span>\u00a0<\/span><\/li>\n
          • Use the scissors to drill a hole in the center of the lids. The diameter should be about 5 mm.\u00a0<\/span>\u00a0<\/span><\/li>\n
          • Fill one of the two bottles with water, leaving about five centimeters of air at the top.\u00a0<\/span>\u00a0<\/span><\/li>\n
          • Screw the second, empty bottle onto the top of the connector.\u00a0<\/span>\u00a0<\/span><\/li>\n
          • Turn the two bottles over so that the full bottle comes up.\u00a0<\/span>\u00a0<\/span><\/li>\n
          • Spin the water in the top bottle by swirling. This requires some practice. Swirl the bottle like a large glass of water, always in a circle, as if you were stirring in a large saucepan.\u00a0<\/span>\u00a0<\/span><\/li>\n
          • Keep the bottles still and watch!<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

            Observation:\u00a0<\/span>\u00a0<\/span><\/h2>\n
              \n
            • A vortex funnel forms in the upper bottle\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

              Tips:\u00a0<\/span>\u00a0<\/span><\/h2>\n
                \n
              • If the connection isn’t completely tight, place a bowl underneath it or experiment outdoors.\u00a0<\/span>\u00a0<\/span><\/li>\n
              • Experiment with turning the bottle slower or faster\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

                Didactic potential:\u00a0<\/span>\u00a0<\/span><\/h2>\n
                  \n
                • The bathtub vortex exerts a great fascination!\u00a0<\/span>\u00a0<\/span><\/li>\n
                • The shape of the vortex can be explained theoretically with secondary school mathematics: The vortex is a consequence of the conservation of angular momentum:\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

                  1. Task: <\/span><\/p>\n

                    \n
                  • Explain why a water particle m in a water vortex rotates faster (i.e. greater rotational velocity v ) the closer it gets to the axis of rotation! This happens when it is sucked into the vortex.\u00a0\u00a0\u00a0<\/span><\/li>\n<\/ul>\n

                    2. Task: <\/span><\/p>\n

                      \n
                    • Show: The surface forms a rotational hyperboloid!\u00a0\u00a0<\/span><\/li>\n
                    • Note: The inclination of the water surface (angle \u03b1 ) results from the sum of the forces of centrifugal force and the weight force of the volumetric piece. (Forces in the rotating reference frame)<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

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