Chia seed slime

After we played with oobleck a couple of weeks ago, I spotted a post about chia seed slime on social media.  I hadn't seen this before, so I had a look into the science behind it before deciding to give it a go with my sons.  Chia seeds absorb many times their mass of water because each seed has lots of mucilage surrounding it.  This forms a gel-like substance around the chia seeds, surrounding the seeds in water whilst they germinate.  If this is mixed with cornflour (cornstarch in the US) which we used for oobleck, it creates a slime-like consistency which is a thicker non-Newtonian fluid. It will slowly adopt the shape of the container it's placed in, and is significantly less messy than oobleck which drips everywhere!

Chia seeds after soaking overnight in yellow water

I decided that I'd have a go at making it first in case it wasn't as simple as it looked, making some for my youngest son to play with - he'd loved the oobleck so I .hoped he'd like this too.  I thought my eldest might find the making process more interesting than playing with it, so once I'd found the right quantities I got him to help make his own chia slime to play with.  I decided to go with a rainbow effect so we could also talk about colour mixing and because I thought multicoloured slime might be more visually appealing for the younger one.

Multicoloured chia slime

To start with, I soaked chia seeds overnight in the fridge.  I used a 1:7 ratio of chia seeds to water, measuring with a set of measuring spoons.  For one small boy's portion of slime, I used a 5ml measure of chia seeds and 35ml of water in each of 3 pots, one with a few drops of red food colouring added, one with yellow and one with blue.

Mixing coloured slime

To make the slime the next day, I took 15ml of chia/water mix and added it to 22.5ml of cornflour.  We have 7.5ml and 15ml measuring spoons, so this is straightforward, but you may want to adjust the quantities to fit whatever measures you have - it's a ratio of 12 parts cornstarch to 1 part chia and 7 parts water.  For the secondary coloured slime (green, purple or orange), I took 7.5ml of each of the constituent primary coloured chia/water mixes e.g. yellow and blue for green.  I mixed them well with a spoon, then kneaded them a little on the work surface.  It should be soft and spread out slowly, if it's crumbly, add a drop of water and if it's too liquid, add a little more cornflour.

Scooping the slime

This all worked fine, so I put out six blobs of different coloured slime for the little one (who was napping) and measured out six containers of cornflour for the big one.  Cornflour is really fine and goes everywhere so I didn't fancy letting him measure it himself, but I got him to add the coloured chia mixes.  This gave a bit of practice colour mixing as I got him to tell me which combinations of colours he needed to use.  We also talked a bit about the chia seeds, where in the world they grow (Mexico or Guatemala) and how they hold the water around them as the seedlings will need water to grow when they germinate.  He had a look at a few with his magnifying glass too, although he was pretty underwhelmed - I think under a microscope they probably look quite interesting!

Enjoying watching it ooze through his hands

He had a surprising amount of fun mixing, and was quite curious about the texture of what he'd made.  He asked for a scoop to use to play with it, and whilst I'd envisaged it being a hands-on thing to play with, he's not a great fan of mess on his hands so this seemed like he'd thought of a way to play with it on his terms.  He did a bit of scooping and layering the colours, and then - much to my surprise - started poking it and making hand prints.  Having discovered that it came off his hands pretty easily, he progressed to picking it up and watching it slowly change shape and drip onto the table.  He played with it for about 15 minutes before his brother woke up!

The slime I'd left out in little blobs for the smaller one had gone a bit solid by the time he came to play with it.  A quick spray of water remedied this, and he gave it a bit of a poke and then turned his nose up at it.  His brother tried to show him how fun it was, but even that didn't help and he went to play with something else instead.  Not what I'd have predicted, given the little one's enthusiasm for oobleck and the bigger one's reluctance to play with it, but the bigger one went on to ask to play with it again the next day (after it had been stored in the fridge overnight) - it needed a quick spray of water to get it back to the right consistency as it had dried out a little before it was put in the fridge.