Learning on Material Science: Meet the Oobleck

What we wonder?

What happen if we add cornstarch with water?

What we need?

1. Cornstarch

2. Water

3. Food coloring

What we do?

1. Mix water with cornstarch. The ratio is 1:2, water:cornstarch.  (If you want more solid oobleck, add more cornstarch).

2. Drop in few drops of food coloring. We choose green because Dr Seuss said it should be green.

:)

Result:

The mix will produce a goo, which does not splash if we hit it quickly.  But if we just let in on our palms, it will drip.  If we hit oobleck with hammer in quick hitting, it acts like a hard material like solid.  But when we let it on the table, it will flow like a liquid.  So what is it this oobleck?  Solid or liquid?

What actually happened?

Sir Issac Newton stated individual liquids flow at consistent, predictable rates.  However, this cornstarch goo does not follow those rules-it can act almost like a solid and then flow like a liquid.  The oobleck is a suspension, meaning that the grains of starch are not dissolved, they are just suspended and spread out in the water.  

How I explained to them?

As much as I didn't get what is it all about with this non-Newtonian liquid, I just simply let them explored.  I explained nothing to them, but I asked them simple question: Iris Iesha rasa oobleck ni apa?  Solid or liquid?

Oobleck under microscope

So how did we apply to our real life? We watched Barbapapa, a short cartoon series from France.   (Consider real life application-lah kan?;P) I personally believed these Barbapapas are actually oobleck goo because they can easily change to many shapes.  We love these cartoons because there are so many uplifting environmental message and animal fun.