Oobleck

What you need:

• Cornstarch

• Water

• A medium to large container

• Paper towels

  
  

What you do:

1. Mix two cups of cornstarch with one cup of water.

2. Start playing around with your measurements.

3. Add a bit more cornstarch and or water to get to the point that you can pick it up, but it's still runny.

4. Play with it! Try to pick it up in your hand, squeeze it, push it, draw it in and more. What else can you do?

Questions to ask:

1. Does your Oobleck feel more like a liquid or a solid?

2. What observations can you make about Oobleck?

What's the science:

Oobleck is a Non-Newtonian fluid, which means that it changes its viscosity (or ease of pouring) not based on temperature, but based on stress caused by stirring, squeezing and adding pressure.

The most common explanation for how Oobleck works comes from Cary Sneider in "Oobleck: What Do Scientists Say?" When Oobleck is still, tiny starch grains are surrounded by water. The water acts like a slippery cushion, letting the grains slide past each other easily. But when you move it quickly or press on it, the water gets pushed out, and the starch grains jam together—making the mixture feel solid for a moment.