It’s a solid! It’s a liquid! It’s a…non-newtonian liquid?!
Maybe you remember reading Bartholomew and the Oobleck as a kid. Maybe you like to play with substances that defy classification. Either way, you might want to try this super-easy experiment.
You will need:
- 1 cup corn starch
- 1/2 cup water
- food coloring (optional)
Start with the water in a bowl and stir in the corn starch a little bit at a time. Eventually, you’ll have to ditch the spoon and combine the mixture with your fingers. You may want to add more or less corns starch, depending on how it mixes together and what consistency you prefer. When it’s as gooey and weird as you want it to be, add a few drops of food coloring, if desired.
If you’ve ever sat through a science lesson, you’re probably familiar with the three states of matter and their characteristics. A solid remains in a consistent shape and volume. A liquid takes the shape of whatever container it’s in, but the volume stays the same. A gas takes the shape of its container, but its volume also becomes that of its container.
So which category does the oobleck fall under?
Try pouring the oobleck into another container. Seems pretty liquidy, right?
Now try pushing on it with the flat of your hand. Pretty solid, huh?
Try rolling the oobleck into a ball. While you’re rolling it, you should feel the ball solidly forming — but as soon as your hands stop moving, it melts back into a liquid form.
Solid or liquid, then? Actually, neither of the above. Oobleck is, in fact, a non-newtonian liquid, which is defined as one whose viscosity, or ease of flow, varies with applied stress. When you’re not applying extra pressure, it behaves more or less like any other liquid. When you do apply pressure (for example, with a solid object or sound waves), the viscosity increases and the oobleck behaves more like a solid.
Oobleck even allows you to walk on a (non-newtonian) liquid, as the Mythbusters found out:
