It's been almost a year since we have played with the curious properties of a cornflour/water mix.  Since I started my blog last July, I've learnt that it's often referred to as oobleck after a substance in a Dr Seuss book.  Anyway, time fades the memory of just how messy this stuff can be in little hands (and all over their faces, feet, and anything they come into contact with) and my littlest is now at the point where I thought he might enjoy it so I made some more.

Playing together with oobleck

It's a mix of 1 part water to somewhere between 1.5 and 2 parts cornflour (I think it's called cornstarch in the US and other places, we're in the UK).  I actually just made it by tipping the cornflour we had left into a bowl and then adding water until I got to the right consistency.  It should behave like a liquid when it moves slowly, and like a solid when it's moved rapidly - if you want to know more about the science behind it, my previous blog linked to above has more details on this.

I thought it'd be fun for my 3.5 year old and the little one might show an interest.  As it happened, my 3.5 year old wasn't very impressed at all, particularly when he found it was messy, but my 16 month old played with it for half an hour.  I put it on what's left of our lawn after the hot weather to make the cleanup easier, and gave him a yoghurt pot, a scoop and the funnel from our science set.  He industriously scooped, poured and found his hands got stuck when he moved them quickly.  He likes pouring water between containers and this stuff clearly behaved differently, which appeared to fascinate him. 

The small one was fascinated

I largely left him to his own devices as he seemed so content.  My eldest has never really taken to sensory play, but the little one seems to enjoy it more.  I joined him for a while when he started to show signs of getting bored and showed him a bit more of the shear thickening properties, moving my hands through it quickly, picking up large apparently solid chunks and show them turning to liquid and dripping through my fingers.

It was definitely messy

It was definitely a messy activity as you can see from the last photo, and it's questionable the amount of science he learnt.  However, whilst my 3.5 year old was playing with it too, we talked a bit about things that are liquids which you can pour (he decided water and milk were examples) and things that are solids which you can't (like wood), and that oobleck looks like it can be either depending on how quickly you move it.  There was also a surprising amount of co-operative play between the two of them for those few minutes, with the little one scooping into the funnel the big one held and them both watching the way the oobleck scooped, poured and drizzled through the funnel.  The mess makes me hesitant to repeat this again in a hurry, and I forgot to make sure it was dried out thoroughly so we could store it, but I'm sure we'll have another go in a few months' time.