Oobleck is pretty much what it sounds like. “Ooh! BLECK!”
Actually it’s Non-Newtonian Fluid. Which means it’s a fluid that doesn’t act like a fluid according to newtons laws of physics. It’s often referred to as Oobleck based on a Dr Suess story called “Bartholomew and the Oobleck”.
This particular Non-Newtonian fluid is a sheer thickening fluid, which means the viscosity increases with the rate of shear strain.
Or more simply – it’s a fluid that acts like a solid when it’s pressed on, squeezed and rolled, but goes runny when it’s handle gently.
It’s corn flour and water.
To set up this experiment
I gave my children a large but shallow mixing bowl each, water, food dye and 1 cup of corn flour to start with.
The fun starts with simply combining the ingredients and finding the optimal ratio of corn flour to water which is 1 part water to 1-2 parts of corn flour.
Mixing it together can be a bit stiff as your get closer to optimal Oobleck consistency and the best way to mix through the corn flour and water evenly is to use your hands – that might be a job for the kids! As we discovered it is very easy to add too much water so help little ones add water in small increments otherwise you might just end up with runny sludge.
Try these experiments:
- Tapping the Oobleck firmly, compared to gently resting a hand in the mixture.
- Stirring the Oobleck with a spoon fast and slow.
- Rolling a ball of Oobleck then release pressure on the ball and watch it ooze back to a fluid.
- Scoop and pour the Oobleck with a cup or spoon.
- Drip Oobleck on a flat surface.
- Experiment by adding more corn flour or water and seeing how the mixture changes.
- Just squish it, squeeze it, rub it and get messy!
- If you happen to have a lot of Oobleck – like 8,000 litres of it – you may want to consider doing this:
For cleaning up the Oobleck will wipe away with a damp cloth, though you may want to wash down the kids in the bath or shower! You can keep the Oobleck to play with again, just cover it over with cling wrap or pop it in a seal container, it will dry out so add more water and stir it through! When you are completely done with your Oobleck discard it in the rubbish bin.