Ryne And Hallacy

Abstract
A couple of years ago, Scientific American ran a short from Nature describing that a spinning cylinder filled with water could form various, unusual shapes under various rotational speeds. We (Ryne and myself) hope to replicate this experiment.
Hypothesis
We predict that, under speeds of one to seven RPS, the water in our cylinder will form various shapes including: a triangle, square, hexagon, and pentagon. This is in line with the results from the Scientific American article.
Procedure
1. Locate cylinder 13-20 cm (5-8 in) in diameter
2. Fill about halfway with water
3. Secure lid on cylinder
4. Attach cylinder firmly to some sort of rotational device (ours was a High-G accelerator built in class.
5. Spin cylinder starting at 1 RPS. Slowly build up speed to 7 RPS.
6. Record step 5 with camera.
Sketch
HighG
Observations
The cylinder failed to create any special shapes except a circle. Near 7+ RPS, the cylinder became unsteady. Water also flew out from the lid.
Results
Due to an insecure lid and binding to the High-G accelerator, our experiment did not produce the predicted results. The water only formed circles instead of the geometric shapes we were looking for
Analysis
The cylinder was off-center, so the cylinder was already experiencing off-balance centripetal forces. This disturbed any equilibrium that might have occurred. The non-secure lid leaked water, and the insecure binding made the off-center cylinder fly wildly around the accelerator.
Calculations
(coming soon)
Conclusion
Our experiment did not work as predicted. Instead of forming different shapes the water went up along the side of the container and only ever created circles. In further experimentation, we will need to secure the lid and binding better and on center. We will also need to use a bucket with sides that go straight up and down. This well help the water be centered and therefore allow it to make polygons
Video
BucketWater.wmv

Website that shows the expected conclusions from our experiment
http://physicsworld.com/cws/article/news/24892

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