Hi Ursula,
is this the book you recommend? https://www.goodreads.com/book/show/161179929-jupiter-the-gassy-giant
The framework of inquiry has been designed to help you planning for inquiry activities that help children learn science through the inquiry process. You might go deeper into the children’s understanding of colour with Jupiter as your theme with this resource from spaceweek.ie https://www.spaceweek.ie/wp-content/uploads/2020/04/Gas-Planet-Clouds.pdf
The children could predict which colours they would get when they mix the food colouring – perhaps referring to their understanding of paint. Then the inquiry process would show them if their understanding was correct.