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| Image credit: www.albionlibrary.org |
This week I experimented with Oobleck. In class, I have been studying mass, volume, density, and particles. I made Oobleck from cornstarch and water, adding 200 mL of cornstarch to 100 mL of water a little bit at a time. This relates to my learning because we've been learning about how the density of particles affects the state of matter of a substance, and Oobleck is unusual because it has properties of both a solid and a liquid matter.
When you move Oobleck around or apply pressure, the Oobleck feels solid, but when it's still, it melts into liquid. When I looked at the Oobleck, it looked like a blue (because of added food coloring) liquid, and when I shook the plastic bag I had it in, it moved like a liquid. The Oobleck smelled like cornstarch, predictably, but its most interesting feature was definitely how it felt. Through the bag, it felt liquidy, but when I squeezed it, it felt kind of doughy. Once I took some of it out, though, I could make it solid by moving it around but when I set it down, it melted into a waxy puddle.
When I was playing with the Oobleck, the results were mixed. When I poked my finger into the Oobleck slowly, it felt like I was sticking my finger in a liquid. When I poked it quickly, it felt like I was poking a solid. When I was transferring it from one bag to another, it poured like a liquid. I succeeded in rolling the Oobleck into a ball by keeping it constantly in motion, but when I stopped touching it, it became a liquid again. Bouncing the Oobleck was unsuccessful - it melted as soon as it touched the table.
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| Image credit: www.utwente.nl |
My experiments have shown me that Oobleck is a non-Newtonian substance, which means that it's neither a solid nor a liquid, but possesses properties of both. When pressure was applied, or it was kept in motion, the Oobleck was a solid, but when it was left alone, it was more of a liquid. From what I learned in class, I can hypothesize that by applying the pressure that makes it feel solid, I'm actually pushing the particles of the substance closer together. That would explain why it seems to switch between the states of matter. It is a very intriguing substance, and interesting to experiment with.
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