Baking Soda Rainbow Bubbles
Here's a great sesnory play exercise for the little ones. Add some vinegar and food colouring to baking soda and watch fizz and bubble up! Combine different primary colours together to mix different colours! Pour them in gently or use a dripper (the one from the Neurofen pack works well!).
Extension: You can also hide a few things inside like mini dinosaur figurines or Shopkins- add a magnifying glass and paintbrush for them to brush off like a true investigator.