In the cornstarch-water mixture individual tiny particles of cornstarch are suspended throughout the water. A heterogeneous mixture with suspended particles large enough to settle down to the bottom of the container upon standing (usually >1μm) is called a suspension. After you stop mixing the sand eventually settles to the bottom of the container-it separates from the liquid. If you mix particles larger than 1μm, such as sand with water the sand does not dissolve.
![oobleck non newtonian fluid oobleck non newtonian fluid](https://vjarv91malaysia.files.wordpress.com/2014/03/dscn0048.jpg)
In contrast, heterogeneous mixtures are not uniform in composition. Such a mixture is called a homogeneous mixture, or solution. For example, if you mix salt with water the salt disappears-it completely dissolves such that the water and salt can no longer be separated. Usually one of two things happen when you mix a solid and a liquid: the solid either dissolves or it separates from the liquid. In addition to being a non-Newtonian fluid, Oobleck can be called a heterogeneous mixture. The more pressure you put on the Oobleck the more solid-like it becomes. When you did not poke at it, but instead just placed some on your fork or held it in your hand, the Oobleck again changed, this time becoming a runny liquid. When you put stress on it, such as by pressing down on it or poking it with the fork, it became harder, changing into a solid. However, since the Oobleck is a non-Newtonian fluid you should have seen that it does not behave like this. Water, and most fluids, are Newtonian fluids and behave in this way. Additionally, the harder they get pushed, the faster the liquids move out of the way.
![oobleck non newtonian fluid oobleck non newtonian fluid](https://i.pinimg.com/originals/0c/c4/19/0cc419433fb6bee80db44a6be2af77a4.jpg)
When most liquids are pushed against, like how you poked the Oobleck with your finger or fork, they move out of the way. The Oobleck you made in this activity is a non-Newtonian fluid, which means it does not act like most fluids (water, juice, liquid detergent etc) you interact with. Do not pour Oobleck down the drain- it can easily clog pipes! What Happened? When you are done playing with the Oobleck, dispose of it in a trashcan.