Mount Fuji erupts!
We love making things fizz and erupt using bicarbonate of soda and vinegar – see my post on Bicarbonate of soda and vinegar: the science behind it. And Mt. Fuji is so famous as a volcano in Japan (although its last eruption was 1707!). So we decided to make Mt. Fuji erupt.
For this, we first took a plastic squeezy honey bottle (empty, washed and dried) and cut the top 1/3 off. We then painted the bottom black and the top white to be our Mt. Fuji. Into this we put a couple of teaspoons of bicarbonate of soda. In a separate jug, we squirted some vinegar and then dyed it red with food colouring (purely for aesthetics!).
My preschooler then slowly poured the red vinegar into Mt. Fuji…and watched it erupt with glee! Note we did this on a tray covered in kitchen towel to minimise the mess.