Toddler activity: transform cornstarch into oobleck

Age range: 10 months to I'll let you know when Boo loses interest
Setup difficulty: Moderate
Equipment needed: Cornstarch, water, a large bowl, a splat mat

Water is to cornstarch as red underwear is to Clark Kent. It is transformative. Cornstarch mixed with water turns into oobleck. And with a name like oobleck it has no choice but to be weird and fun. Oobleck (aka as a non-Newtonian liquid) has the interesting property of acting as a solid when pressure is applied to it and liquid when the pressure is removed. It is a very, very interesting substance to play with.

Setup

 

Pour about a cup of cornstarch into your bowl. With a toddler I recommend using a heavy bowl, one that they can't accidentally tip over with ease. I used a glass baking dish. Add water slowly, mixing with your hands as you go. I find that using your hands is key - it is very easy to tell when you've got the proportions right if you use your hands. You've got it just right when you have a thick liquid that flows slowly and if you squeeze it you can make a ball. Remember that mistakes are very easy to fix. If it is too runny, add more cornstarch. If it is too thick, add more water. 

Put down your splat mat, place the bowl on the mat. This activity really works well sans clothes, as you will see from the pictures below.

So what is the deal with the 'moderate' difficulty rating for this simple two ingredient activity? Clean up. This can get very messy and require some effort to clean up. It is well worth it though, I promise.

Play!

 

Boo, her squeaky shaker firmly in hand, makes her first foray into oobleck land. K's curiosity is piqued too.

See what I meant about messy? She had such a great time picking up handfuls of the stuff, rolling her toy in it, putting her foot in it.

Here is Boo in action with the oobleck.

K loved oobleck too. He really, really, really wanted to eat as much of it as he could, so he ended up being rather helpful during cleanup.