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!
You can find out more about the science behind this experiment here, and get some ideas for experiments to perform with your new creation here.
Have fun, and remember to visit the Jobs in Childcare blog for more fun activity ideas, including base building, a recycling experiment, a time capsule or a treasure hunt.
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