Plasticity

In class, we did a lab to see how the mantle flows and has the property of plasticity. So we put cornstarch into a beaker and combined it with water. At first, it looked like a liquid batter. But when I put my hand in it, and then rolled it around, it hardened and felt like hardened wax. When I poked my finger in quickly, it made an indent that filled in quickly. I poked it slowly, and the mixture settled around my finger. So, supposedly, this is similar to the mantle's texture.