Your Challenge: Create a non-Newtonian substance that behaves like both a solid and a liquid!
What You Need
- Measuring cups
- 1 cup of cornstarch
- 1/2 cup of water
- 1 large bowl
- Food coloring (optional)
- Lay out some newspaper on a table--this project will get very messy!
- Measure out 1 cup of cornstarch and pour it into the bowl.
- Add a couple of drops of food coloring into the bowl, if you wish.
- Now, slowly add water into the bowl--mix it into the cornstarch with your hands.
- Keep adding water until the oobleck feels like a liquid when you're mixing very slowly, but resists motion when you try to mix it faster--at this point, your oobleck is done!
- Try picking up a handful of oobleck and squeeze it in your fist. How does it feel?
- Now, let the oobleck just sit in your hand. Do you feel like it has changed?
How It Works
Oobleck is a non-Newtonian fluid, or a fluid that doesn't behave the way fluids we think of as "normal," like water, behave. Oobleck, in particular, is interesting because its viscosity, or its resistance to flow, increases when pressure is applied to it. That is why when you squeeze it in your hand, it feels like a solid, but when you let it sit in your palm, it flows like a liquid. This property of oobleck comes from the structure of the cornstarch grains, which tangle and "lock up" when pressure is applied, causing the oobleck to act like a solid under pressure!
- The name "Oobleck" comes from the Dr. Seuss book Bartholomew and the Oobleck.
- Quicksand is a non-Newtonian fluid similar to oobleck that can be found in nature.
- If you move fast enough, you can walk across a pool of oobleck without sinking!