How to Make 'Concrete' Oobleck for Sensory Play

by Laura

Laura @inspiremyplay

Founder of @inspiremyplay, Early Years teacher for 11 years and mummy to three gorgeous girls. I'm passionate about the benefits of play in early childhood.

If your child loves cars and diggers, this concrete oobleck recipe is the perfect sensory play activity to try at home.

Made using just a few simple ingredients, this construction-themed oobleck looks just like wet cement and creates the perfect base for imaginative small world play. Children can scoop, pour, mix, build and create their very own construction site while exploring the fascinating science behind this unusual sensory material.

Whether you're looking for an easy sensory activity for toddlers, a fun STEM activity for preschoolers or a creative way to encourage open-ended play, concrete oobleck is always a hit!

What is Oobleck?

Oobleck is a mixture of cornflour (also known as cornstarch) and water that creates a non-Newtonian fluid. This means it behaves differently depending on how much pressure is applied.

If you press or squeeze oobleck, it feels firm and can be moulded into a solid. But when you let it go, it flows through your fingers like a liquid.

This makes oobleck a brilliant sensory play material as children can explore cause and effect while discovering early science concepts through hands-on play.

Try pressing a spoon firmly into your oobleck and you'll notice it feels much harder. Move the spoon slowly through the mixture and it begins to flow around it. It's a simple experiment that helps children understand how materials can change depending on how we interact with them.

Why Children Love Concrete Oobleck

Construction play is a favourite for many children, and adding oobleck creates a fun new sensory material to explore.

Children can pretend to mix cement, build walls and create their own construction scenes using diggers, trucks and building materials, like our mini bricks and blocks.

As they’re playing, they're developing:

Fine motor skills through scooping, pouring and building.
Creativity and imagination through small-world play.
Problem-solving skills as they experiment and create.
Early STEM skills through exploring textures and materials.

Best of all, there is no right or wrong way to play. Children can unleash their imagination and create their own construction adventures.

How to Make Concrete Oobleck

You will need:

2 cups (240g) of cornflour (cornstarch)
1 cup (240ml) of water
Black food colouring
PlayTRAY
Construction-themed play materials like diggers, bricks and blocks

We made ours in our PlayTRAY, which is perfect for sensory activities thanks to its deep sides that help contain messy play. The lid also makes it easy to store your setup and return to play another day.

Method:

Pour the cornflour into your PlayTRAY.
Add a few drops of black food colouring to the water and pour it on top of the cornflour.
Stir until the two ingredients are fully combined.
Add your construction materials and let the building begin!

The mixture may feel tricky to combine at first, but keep mixing and it will gradually come together.

Create Your Own Construction Sensory Bin

Once your concrete oobleck is ready, it's time to turn it into a construction site!

Add diggers, trucks, loose parts and building materials to encourage imaginative small-world play. Children can use the oobleck as their "cement" to build, stack and create.

For our construction setup, we used:

Mini bricks and blocks for building walls and structures
Construction vehicles for digging and transporting
Scoops, bowls and funnels for mixing, pouring and moving the oobleck
Pebbles and gravel to add extra texture

Our Mini Bricks and Mini Blocks are especially fun with concrete oobleck as children can stick them together, knock them down and rebuild again and again!

Helpful Tips for Making Concrete Oobleck

Getting the perfect oobleck consistency can take a little experimenting.

If your oobleck feels too runny and doesn't hold together when picked up, simply add a little more cornflour.

If it feels too solid and doesn't move like a liquid, add a small amount of water until it reaches the right consistency.

Oobleck can get messy, so we recommend placing your PlayTRAY on a wipe-clean surface, placing a mat underneath, or taking your sensory play outdoors.

Once playtime is finished, pop the lid onto your PlayTRAY to help keep your oobleck ready for another play session. Without a lid, oobleck will dry out after a day or two.

Don't throw it away when it dries though! The leftover chalky texture can still be used for messy play, scooping activities or creating a brand-new sensory setup.

Extend the Play

There are lots of ways to continue the fun once your construction oobleck is ready.

Try adding:

Toy construction workers
Road signs
Wooden figures
Natural materials like sticks and stones
Sensory tools, like our scoops, bowls and tongs

You could even create a different themed small world using the same oobleck base, like an alien planet!

More Sensory Play Ideas

Looking for more sensory ideas? Explore our range of Sensory Play Activity Cards, packed with easy recipes, themed setups and creative play invitations designed to make sensory play simple for busy parents.

From construction sites to messy swamps, there are endless ways to encourage children to explore, create and learn through play.