Sunday 2nd of June was the Keele Community Day and we were on Science is Fun duty! This year we went for a hands-on activity and a demonstration. We did a demonstration of Elephant’s Toothpaste, also known as the catalysed decomposition of hydrogen peroxide with a bit of dish soap for maximum bubble production. It wasn’t the glow-in-the-dark version I perfected for my demo lecture a few weeks ago because we were outside and had limited washing up facilities, but it was pretty good. For hands-on, we went for PVA-borax slime thinking that it would have broad appeal to most age groups.
Our gazebo of science fun. Tom (1st year chemistry student) is in the lab coat trying to drum up business. We were grateful for the gazebo – it was a warm and sunny day! In addition to Tom, five other 1st and 2nd year chemistry students came to help.
And a close up of Dr Darton making some green slime with Jim.
Kit-wise, generally we go for disposable plastic cups and lolly sticks as reaction tubs, plastic sealable bags to cart the product home (with stickers stating ingredients and a safety message), 4 wt% PVA in bottles to be measured (25 mL generally sufficient), and 4 wt % borax in bottles. I went for pump-action bottles of the kind used for hand lotions and they were a big hit. One pump was around 2 – 3 mL so three or 4 pumps was sufficient. Having recalled frequent food dye spills from when we did this kind of activity before (using the food dye bottle and plastic pipettes), I decanted the food dyes into eye dropper bottles. It’s important to make coloured slime!
We’re thinking about investing in a stack of plastic beakers to reduce the waste of this activity. We expected to make slime with around 100 people, we packed kit for 200 people with a bit extra spare, and I took 300 plastic cups down. There were a few points where I was heading back to Lennard-Jones (the Chemistry department to replenish our supplies). In the end, we took 20 plastic cups back to the labs and reckon we interacted with around 800 people.
For the Elephant’s toothpaste, we used 12% hydrogen peroxide (it didn’t need to be quite as spectacular as 30%), 2M potassium iodide (make fresh and/or keep in dark bottles), dish soap and a little food dye for good measure. We use a measuring cylinder (plastic of course), and a basin to contain the foam fest. It was difficult cleaning the foam out of the measuring cylinders between times – we had wash bottles but no sink. The demo was good, but many visitors were distracted by the slime!
All in all, a good day!