Walking on oobleck

A couple of years ago my children took part in Mini Mudder, one of the obstacles was a huge tray of cornflour which everyone loved, so when TTS Group kindly sent us a Messy Play Grab and Go Kit including a giant bag of cornflour we thought we’d try to create a smaller version in our garden.


Giant oobleck tray


What is oobleck?

Oobleck is a mixture of cornflour and water. To make our giant oobleck tray I poured about 1 kg of cornflour into a large black tray and slowly added water until the consistency was wet, but solid when squeezed.

The funny thing about oobleck is that if you scrunch it up in your hand it feels solid but if you unclench your hand and let it run through your fingers it flows like a liquid. We call oobleck a non – Newtonian fluid as it doesn’t flow like liquids normally do.

Cornflour oobleck is made up of molecules arranged in long chains. When the chains are stretched the liquid will flow, but when you force them together they stick together to form a solid.

Giant oobleck tray


You can see from the photos how much fun we had. It is a lot of cornflour, but I left the tray to try in the sun and then scooped up the dry powder so I’m hopeful we can use it again.

Giant oobleck tray

We trying walking, running and even cartwheeling over the oobleck. The children found that if they ran quickly over the surface their feet stayed dry, but if they walked slowly they started to sink!

Once the big children had finished playing for day we added some plastic fish and turned it into an ocean play tray for the littlest member of the family.

Giant oobleck tray


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