Plasticity Lab

Is the earth's mantle a liquid or a solid? It's pretty hard to tell. Actually, its a solid that acts like a liquid because it has plasticity. When left alone, it is a liquid. However, when you apply heat and pressure to it, it becomes a solid. Pretty cool, huh? None of use can go and play with the earth's mantle, but I got to do an experiment to see just how it works. For our experiment, we too 5 teaspoons cornstarch and mixed it in with 10 ml of water. We added blue food coloring just for fun. Be careful, certain colors of food coloring will stain your hands, such as blue and green. after mixing well, I took some in my hands. It was so fun to play with. It was gooey, but hard. It could slip out of you fingers, but be formed into a ball at the same time. This was the most exciting thing I've done in science, and the most fun! I really couldn't tell if it was a liquid or solid because it had the characteristics of both a liquid and a solid. When you squeeze the mixture, it forms a ball. If you squeeze it for a longer amount of time, it starts to ooze out through the cracks between your fingers. When you stick your finger in the mixture fast, a small dent appears but quickly disappears. On the other hand, if you stick your finger in slowly, it will leave a dent for a longer time, but will eventually go away. I think that is really cool. The mixture is similar to the earth's mantle because when you add heat and pressure to the mixture, it becomes a solid, while the same is true for the mantle. However, since the mantle is much larger, it requires a greater amount of heat and pressure to change what it seems to be. Even after knowing all this, I cannot determine whether it is a liquid or a solid. Do you have any ideas?