We were given version A of a “mystery tube” in class on Tuesday and asked to simply make observations and explore this mysterious item as much as we can. It was a white hollow cylinder with a string that could be pulled out on both sides. Then we realized that on the left side of the mystery tube, the string could be pulled out longer, 24cm, almost twice as long as the right side. The total length of the tube was around 18 cm long, and the string that could extend out from the right side is around 11.5cm long. The string on both sides could be pushed in, too. We also noticed that string wrapped around the left cap of the tube. There was noise when pulling, but no loud noise when shaking. We tried to test the magnetism with a magnetic, and the tube was not magnetic. After making detailed observations, we moved on to making inference. We initially thought about using two moving pulleys, which made it possible to have a string that moves in the same direction but on the two ends of the tube. Then we realized that as long as there’s only one string inside the tube, the two ends of the single string must move at the same speed, which contradicts with the observations. We then came up with the two string version of the sketch model: one around a single moving pulley, another attach the center of the pulley as the sketch will show below. After posting our poster and getting awesome suggestions, questions, and comments from my classmates, we decided that the diameter of the pulley should be as big as the diameter of the tube so that there will be no loud noise when shaking the tube. We started building our scratch model from card paper tube. We cut some circles and glue them together to build a pulley. We put tape around the pulley so that one string can stay within the gap. Here’s a picture of our draft model! We strictly followed the size, shape and length ratio in order to construct our model as similar as the original mystery tube, but we still encountered some problems at the end such as that the pulley didn’t rotate very well and it didn’t always rotate in right angle. The whole string pulling process is not as smooth as the original mystery tube.
“All models are wrong, some are useful”. We can never construct a model that is a hundred percent accurate in every aspect of the object. However, we can learn a lot by simply observing, writing and sketching down inference and possible structure, building the model, and reflect how much alike it is to the original mystery tube. In the process of discovering new species, scientists observe certain traits and build the models based on hypothesis and furthur improve the model as they observe more. It’s possible to get closer to the actual object or organism by improving the models, but It’s unlikely that the models are the exact copies of the objects. However, scientists learn from constantly changing and improving the models.
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November 2018
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