fairy soup - happy hooligans - outdoor sensory activities for kids. This is also a free activity you could consider mentioning to parents; a trip to the local park and then play at home. Also called a messy mixture, or "perfume making"
Mixing potions - this is a super-simple sensory play idea that's especially good for babies, toddlers or preschoolers playing together
Roald Dahl activity ideas: there are some very imaginative activities described…
Little Wizards at Work: Mixing Potions Invitation to Explore. Love this junior science kit!
wonderful science and art projects. 30 Fun Science Projects for Kids