How to make oobleck

Making oobleck was one of the very first science activities I wrote about on Science Sparks. I’ve given this very old post a bit of an update and refresh so I hope you like it!

How to make oobleck

Gloop or oobleck is just cornflour and water. It’s very easy to make and creates a lovely gooey slime which feels solid when you scrunch it up and liquid if you let it flow through your fingers.

how to make oobleck


  • Cornflour
  • Water
  • Food colouring – optional
  • Ice cube trays – optional
  • Mixing bowl
  • Colander, funnel and beakers – optional, but great for messy fun!



  • Fill a cup with cornflour and add to the bowl
  • Add water very slowly mixing with your hands all the time, until you get a sticky, slimy gloop.
  • If you want to make it coloured add some food colouring. ( be careful this can stain skin and clothes)
  • Play with the slime and see how it behaves. Can you make it into a ball? and what happens if you throw it onto the floor?



The Science Bit

Did you notice that if you make a ball with the gloop it is solid, but if you drop it on the floor it turns liquid again? The slime is a non – Newtonian fluid as it doesn’t flow like liquids normally do.

Conrflour gloop 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.


Gloop play ideas

Pretend you’ve run out of superhero slime, can you make some more? – this activity an also be found in Science Sparks the book, along with extension ideas and links to maths and English.

Try squeezing the cornflour into a ball, it should feel solid. Open your hand and watch as the cornflour slime runs through your fingers.

Can you freeze the gloop? Our frozen Kool Aid oobleck smelled wonderful.

Try pouring the slime through a colander, what happens? Can you use the slime to trap a small figure or pretend spider?

 The always amazing Babble Dabble Do has even more fun Oobleck activity ideas for you.

superhero slime

Things to think about

Can you squeeze the slime into a ball? What does it feel like? How long does the ball stay solid after you let go?

If you used less water do you think the slime would fall faster or more slowly through the colander?

  How to make oobleck

There are 15 comments

  1. Ross Mannell

    I always loved this activity. A favourite was rolling a ball in the hands then handing it to a child and watching it collapse. I would then ask what they thought had happened. Their responses could be very creative.

  2. Lisa Hagg

    This is a big hit with my two girls (Emily 4 & Phoebe 2) and features in our Little Explorer classes for toddlers/preschoolers too and it is an activity that is always approached with curiosity, awe and amazement! Loving the picture too, this is a good activity around Halloween time especially if using green colouring. To avoid staining, particularly for younger children, we use waterbased paint to colour the ‘goo’. Thanks Lisa

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