“Non-Newtonian fluid” experiment
How to make a substance that can be both liquid and solid
Can a substance be solid and liquid at the same time? Here’s an experiment to make a non-Newtonian fluid which doesn’t behave by the rules!
Warning! Only under adults supervision.
Reagents and equipment:
- corn starch;
Sprinkle 2 parts of corn starch into a glass bowl and gradually add 1 part of water until a viscous liquid mass forms. Let your imagination run wild as you test the physical properties of the liquid: knead it in your hands, run on it, hit it with your fist or with a hammer.
Non-Newtonian liquids do not obey the laws of ordinary liquids. They change their density and viscosity under the impact of physical force. The stronger the impact on an ordinary liquid, the faster it will flow and change its form. With a non-Newtonian fluid, we get a completely different effect; it starts to behave like a solid body. The bond between the molecules of liquid will increase as the force of the impact on it increases. The viscosity of non-Newtonian fluids grows as the liquid begins to flow more slowly. These liquids are usually highly heterogeneous and consist of large molecules, which form complex spatial structures.
To put it more simply, a non-Newtonian fluid is a substance which can be both solid and liquid, depending of the speed of impact on it. If we push, knead, throw or hit it quickly, it behaves like a solid body, but if we stop, then it turns to a puddle in our hands.
Starch particles swell in water and form contacts in the form of chaotically interlaced molecules. These durable bonds are called meshes. Under harsh impact, durable bonds do not let the molecules move, and the system reacts to external impact like a tight spring. Under slow impact, the meshes spread out and untangle. The lattice tears and the molecules separate.