Messy Bubs absolutely loves Science Week as it gives our Messy Bubs a chance to explore and discover a range of science related activities supporting them to know more about their world around them.
How to Make Lemon Oobleck (For Under 5s)
What You Need:
1 cup of cornflour
½ cup of water
Juice of 1 lemon
A few drops of yellow food coloring (optional)
A large mixing bowl
Instructions:
Pour the cornflour into the bowl.
Add the lemon juice and mix well.
Slowly add water while stirring, until the mixture reaches a thick but runny consistency. It should feel solid when you press it but turn liquid when you let it go.
Add a few drops of yellow food coloring (optional) and mix until evenly coloured.
Play! Let your Messy Bub explore the texture with their hands.
Tip: Oobleck is non-toxic but not edible, so keep an eye on little ones to prevent tasting.
Oobleck is a fascinating substance because it behaves as a non-Newtonian fluid. Here’s the science behind it:
What is a Non-Newtonian Fluid?
Most fluids, like water, are Newtonian fluids, meaning their viscosity (resistance to flow) remains constant regardless of the force applied to them. However, non-Newtonian fluids like oobleck have a viscosity that changes when stress or force is applied.
How Does Oobleck Work?
Oobleck is made from cornflour and water. Cornflour is composed of long chains of starch molecules. When you mix cornflour with water, these molecules are suspended in the water. The interesting part happens when you apply force:
When you apply force quickly (like poking or squeezing): The starch molecules get pressed together, and the mixture behaves like a solid. The sudden force doesn’t give the water time to move out of the way, so the starch particles jam together, creating a temporary solid structure.
When you apply force slowly (like letting it drip or gently pressing): The water between the starch molecules has time to move, so the mixture behaves like a liquid and flows easily.
Why Does This Matter?
Oobleck demonstrates the concept of shear thickening, where a material’s viscosity increases with the applied stress. This is why it feels solid when you squeeze or hit it but turns liquid when you hold it gently.
This makes oobleck not just a fun sensory activity for kids but also a great way to introduce them to basic scientific principles of materials and fluids!
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