Structure of the Earth: Plasticity Lab

Recently, we did an experiment on plasticity in the earth. Plasticity is pressure inside the mantle. In this lab, my group and I were suppose to make a mixture that introduced us to the form of plasticity. The materials used for this lab were cornstarch, water, 2 small beakers, and a spoon. We first put 5 teaspoons of cornstarch in one beaker, and 20 milliliters of water in the second beaker. Then we poured the water into the cornstarch, and stirred. It was difficult to mix this white mixture, and that means we did the lab correctly. The mixture was liquid-like at first, but dried to a solid form. A few of our group members put their fingers in the mixture to feel the substance. When they put their fingers in the mixture quickly, the mixture acted like water and did not do anything. But, when they put their fingers in slowly, the mixture made a solid-like formation around their fingers. Next, one of our group members pick up some of the mixture and played with it in their hands. When the mixture was in a open hand, it was liquid-like, yet when the person closed his hand, he said it felt like a solid. Therefore, I came to the conclusion that when this substance was under pressure and heat, it became hard-like, and when no pressure and heat was applied, it was liquid-like. I also realized that this relates to the mantle of the Earth as well. The mixture was similar by its movement. The mantle moves like a liquid, yet when added with pressure and hear, it becomes solid-like. The asthenosphere is liquid-like because there is less pressure that in the lithosphere, which is solid-like. This lab made me understand more about the Earth's mantle. Another odd job that happened was the cleaning up. We could not clean the tables with water, otherwise the excess cornstarch would get gooey again, so we simply had to wipe it off the table. It was something different that we usually do not do in lab clean-up. Overall, plasticity is very interesting. I wonder how scientists discovered plasticity and how they researched it and are still researching it. It is a very fascinating and pertinent topic to studying the Earth.