Oodles of Oobleck!

Some people may see the green stuff on my hand in this picture and think it's gross slime-- but it's not. What is it, you ask? Oobleck, of course! Oobleck is a material that I experimented with in my Language Arts Methods class. We used this in Language Arts Methods because it allowed for us to go from speaking to writing in the classroom. In an actual elementary classroom setting, the lesson would go as followed:

1. Perform an Experiment

2. Introduce Key Vocabulary

3. Teacher Guided Reporting

4. Journal Writing

In my journal, I wrote that the oobleck is a really cool, unique, viscous substance. It's messy and slimy, because at some times its a solid and sometimes it's a liquid. The oobleck is solid when you apply pressure and it is liquid when it is in motion. I like that we experimented with this substance in class because I never really knew that something could act as both a solid and a liquid at the same time.

We did this activity a few weeks ago in class, and I thought it would go perfect with a science lesson. In the handout that our teacher gave us, it said "'Oobleck', named for the mysterious green substance described in the Dr. Seuss classic Bartholomew and the Oobleck, is a non-newtonian fluid meaning it doesn't follow Newton's laws of motion. A non-newtonian fluid (like oobleck or silly putty) has a different viscosity depending on the force applied. By contrast, newtonian fluid (like water) have a constant viscosity at a given temperature. No matter how fast you stir them they never get thicker or thinner".

Oobleck is a mixture of cornstarch and water. Because it's a mixture of a solid and a liquid, it takes on the properties of both, and winds up behaving in unpredictable ways.  In liquids, the bonding between molecules is weak, which allows the molecules to easily flow past one another and rearrange, giving liquids their characteristic properties. In solids, the bonding between molecules is much stronger. The molecules cannot be easily rearranged, so the solid keeps its shape. 

In oobleck, the cornstarch molecules are very large, allowing for them to form long chains. The water molecules are much smaller, so they flow past each other and between the cornstarch molecules so that the chains slide and flow around each other. This explains why oobleck behaves like a liquid when it's not under pressure. When you squeeze or press on the oobleck, the water is temporarily forced out of the mixture and the starch molecules are pressing against each other, causing the mixture to behave like a solid.

I really enjoyed playing with Oobleck in class, and I think that I would definitely use it in my future science classroom. Even though it made a mess, it explains a great science theory that would be beneficial for the students to learn, and they would have fun at the same time. 

Here is a video that we watched in class. Even though the video isn't in English, it shows a really cool way of playing with Oobleck. Enjoy! :)