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How to Make Oobleck: Create Your Own Oobleck with Cornflour

How to Make Oobleck: Create Your Own Oobleck with Cornflour
To make oobleck, mix cornstarch and water together until you get a gooey consistency. You can add food coloring for fun. Oobleck is a non-Newtonian fluid that behaves like both a liquid and solid depending on the force applied to it.

Looking for a quick, simple activity to keep your kids busy this afternoon, why not incorporate learning and fun and try this out?  Have you ever heard of Oobleck slime? If not, read on and find out all about how to create a cornflour slime activity your kids will love!

If you haven’t heard of ‘Ooblek’ before - don’t worry! Neither had we, until we found out that it was a name created by Dr Seuss and given to a substance that you can create at home, in a fun experiment combining cornflour and water.

The cornflour experiment is a great way to learn about non-Newtonian liquids and is fantastic for simply playing around and getting messy. This experiment is suitable for kids aged 5 and over, and younger kids can take part too under proper supervision.

To perform your cornflour experiment you will need cornflour (or cornstarch, as it’s known in the US), some water, a large mixing bowl and some different coloured food colourings (optional!)

When you’ve gathered your materials, it’s time to make your Oobleck in 3 easy steps!

1.First of all, simply pour the cornflour into the bowl and, before adding any water, examine it with your charges. Take note of the texture, the fine grains of the cornflour, and try making imprints with your fingers or other objects. Ask your charges questions about what they feel, what the powder reminds them of, and consider making notes for a ‘before and after’ discussion. This mixture isn’t an exact science - you can use as much or as little cornflour as you’d like.


2. Next, pour in the water. If you want to colour your cornflour you may wish to add the food colouring of your choice to the water being pouring it into the cornflour for an even mix. Alternatively you can add the food colouring after the water - both methods will ultimately produce the same result. Add the water slowly, mixing at intervals to get an idea of how much water you want to put in. Different amounts of water will, of course, produce different consistencies, so don’t rush or you risk having extremely watery Oobleck.

Your charges can keep their hands in the bowl while the water is being added to feel the change in the liquid as the cornflour is diluted.

Soon you should reach a stage where you understand that the cornflour is somewhere between liquid and solid. You should be able to pick up cornflour and squeeze it - it will feel solid - and then see it melt when you release your grip.


3. Play with your Oobleck! Ask your charges to describe their creation. Try picking it up, squeezing it, releasing it. What happens if you try to bounce a ball on top of it? What happens if you drop it from a height, or try to poke holes in it? What if you leave it on a surface to spread out how it wants to? Again, if your charges are of an appropriate age, consider taking ‘after’ notes or even some photographs to conclude the experiment.


When it’s time to clean up, you can wash your Oobleck off with warm water. Just remember to be careful with the food colouring - too much colouring or a particularly strong colouring can colour your charge’s hands. So unless you want to explain to your charge’s mother why he has green hands, be careful! 

Have fun, and remember to visit the Jobs in Childcare blog for more fun activity ideas.