The experiment calls for 1 cup flour (we used expired bread flour): 1 cup baking soda: 1/4 cup oil (we used vegetable oil) – for each colour cloud dough – and some tempera colours.
As mentioned, we made three colours and arranged the colours onto a big tray.
To start the experiment, just spray vinegar into the cloud dough!
Video of them trying the fizzy cloud dough <here>
Outcome of the fizzy cloud dough <here>