Today Mtoto and I became home scientists and we made our own clouds. Really we did loads of things but this was our special experiment.
I found the instructions for this in a book, but there are loads of examples online, it turns out.
An empty gherkin jar
We got the hairspray especially (around 4 CHF in the Coop) but everything else was in stock already. We usually buy our food colouring from our local Migros.
I boiled the water in the kettle and got the ice cube rack out of the freezer. I poured lots of water into the jar and added way too much colouring. Really you only need the water to be 2-3 cm deep and it doesn’t have to be as hot as boiled. You also only need a few drops of food colouring.
I sloshed the water around in the jar, then put its lid on upsidedown. Once I had shown mtoto how to get the ice out of the tray he loved taking responsibility for that job and he carefully placed each cube on the upturned lid.
Then I removed the lid and I sprayed hairspray into the jar and put the lid back on.
Mtoto was amazed by the clouds and loved watching them swirling around in the jar. Some escaped and we were both excited to see the clouds rise. Mtoto was soon in charge of spraying the hairspray into the jar, though I had to help him by holding the can.
We talked about safety issues such as not spilling the water and not spraying hairspray near anyone’s faces.
It was also a great opportunity to talk about how clouds form and Mtoto does ask a lot of questions, so it was a satisfying experiment. So satisfying that we repeated it to show L when we had the play dough out after dinner tonight.
In case you’re wondering, adding hot water to the jar crests warm moist air, which rises and is cooled by the ice above the lid. Then it needs a surface to condense onto to become cloud droplets and the hairspray provides this. As the warm air rises and the cool air sinks, it makes a swirling effect.
It wasn’t clear what the colouring does – perhaps it helps make a colourful contrast between the water and the cloud.