Oobleck

Objective

To demonstrate a Non-Newtonian liquid

Materials

3 tablespoons water (you can use the coloured water from the Water wicking activity)

to make bubbly Oobleck kids can use in the bath use 2 tablespoons of water and 1 tablespoon of bubble bath or liquid hand soap

Cornflour (about 1/4 C)

measuring spoons and cup

bowl

wooden spoon

plate

Difficulty:

Time: approx 10 minutes

Adult supervision: no but

could get messy!

Dangers: none

Instructions

Measure 3 tablespoons of water (or water & bubble bath) and put it into the bowl
Gradually add the cornflour and stir
Keep adding the cornflour until you get to the point where it is getting hard to stir.
Pour the Oobleck onto a plate.
Now watch the Non-Newtonian liquid in action.

When you push a spoon slowly through the Oobleck, it behaves like a fluid and the spoon moves easily through it
When you push the spoon harder (hold onto the plate!!) the Oobleck feels hard, more like a solid
If you punch or poke the Oobleck, it feels hard like a solid

When the spoon is pushed slowly through the Oobleck, it acts like a Newtonian fluid

When more force is used to push the spoon through the Oobleck, it acts like a non-Newtonian fluid

The Science

What is a non-Newtonian liquid?

Physicist and mathemetician, Sr Isaac Newton (1643-1727), developed the principles of modern physics. One of these is Newton's Second Law. This law states that the acceleration (increase in speed) of an object depends on the force applied or push. Water obeys this law. If you push water harder, the faster it flows. However, Oobleck is a non-Newtonian fluid because it doesn't follow this law. The harder we pushed the spoon through the Oobleck, the slower the Oobleck moved.

Bartholomew_and_the_Oobleck-Dr._Seuss_(1

The name Oobleck came from a Dr Seuss book. Oobleck was a gooey green substance that fell from the sky