Hi Rachael,
Dancing Raisins is great fun – both in English and in Irish. It is one of those really nice demonstrations that is easy to extend into an investigation, by responding to the children’s questions.
If they think the raisins are the key part – try with other small items. If they think the fizz is the most important – try with different levels of fizz (perhaps by mixing fizzy drink with water – or by stirring the drink to get the fizz out).
In all cases, the children’s science explanation can be modified in light of what they notice happening.