Joel has been doing outreach at Strathfield North Public School for about a dozen years now – working the whole time with teacher Filomena Catanzariti. For all of those years, I’ve desparately wanted to run over a swimming pool filled with oobleck, to demonstrate the properties of a non-Newtownian fluid (and, after all, who *wouldn’t* want to do it…).

Oobleck is a slurry of cornflour and water (about 1:0.7). It pours like relatively runny pancake batter, but if you apply force to it, it becomes solid for as long as the force is applied.

After a decade of the school knocking back my suggestion (largely on the grounds of messiness), a new principal gave it the green light – yee haa!!

With the aid of Dr Taylor Szyszka – my ever-keen science communication expert (and former PhD student) – I was able to integrate it into a workshop on the properties of materials – which is what the ~150 year 6 students had been studying in science. We started off the workshop with some liquid nitrogen and dry ice capers, including the super-cool (ha ha) Meissner effect – making a liquid-N2 temperature superconductor levitate – and even demonstrating the amazing magnetic properties of liquid oxygen.

Then it was time for the big finale – Keith Rippon in our workshop constructed a trough of exquisite workmanship – 4 m long and built to easily take the 100+ kg of cornflour:water slurry (or a nuclear blast, judging from how heavy it was…). Getting the trough to the school was a bit of a challenge, requiring a 12-seater van with the trough wedged in above all the seats – and leaving *just* enough room for the concrete mixer that we had to hire to mix the oobleck!

Taylor introduced the students to liquid N2 while I set about shovelling cornflour and water into the mixer out on the grass, and then trying to get it all to stay mixed after pouring into the trough. Turned out to be a bit tougher than I imagined – because a liquid that turns into a solid when you apply force is strangely resistant to mixing!

Got there in the end though, and we were able to have a huge amount of fun with the students sinking their hands or feet into the trough and then being unable to pull them out if they pulled too hard – they had a blast.

And of course, the big finale – my run through the trough… worked like a charm (i.e., I didn’t sink!) and a life goal fulfilled! Bring on 2023!

We were also featured on the CSIRO’s blog…[here]