As part of our world around us topic, Natural Disasters, we made volcanoes.
Here is the recipe
half fill a cup with water
add 3 drops of red colouring and stir
add 3 teaspoons of bicarbonate of soda and stir
a squirt of washing up liquid and stir
add a quarter cup of vinegar and stand back
make sure you carry out this experiment somewhere you don't mind making a mess