Katie Stewart on how to teach critical thinking using her very cute picture book What Colour is the Sea?

The importance of critical thinking has become a common discussion topic in the media in recent weeks. And teachers have long known critical thinking is the basis for progress in learning. In this article, writer, illustrator and former teacher Katie Stewart shows how to use her new picture book, What Colour is the Sea?, to start children on the path to critical thinking. Katie has dedicated What Colour is the Sea? to ‘all the wonderful teachers who encourage their students to discover things for themselves’.

Using the book in the classroom

What Colour is the Sea? is on the surface a very simple story, but, looked at more deeply, offers the chance for a lot of discussion. There is no explanation of what Koala is doing, so there is lots of room for talking about what she finds and why she feels happy at the end. Furthermore, it is not necessarily only useful for younger children. With older students, the same concepts could lead to discussion about social media, and the need to analyse what students see and hear and to reason out their own opinions based on research, rather than simple acceptance of what they see. The possibilities are many for the teacher with an imagination.

Curiosity and open-ended questions


Curiosity is the essential ingredient for critical thinking. It is the catalyst that sparks the quest for knowledge and then often stirs the urge to use that knowledge creatively. Fortunately young children tend to have it in abundance. Koala, the main character of What Colour is the Sea?, starts her journey with her question – what colour is the sea? It is a question with no definite answer, an open question with potential for classroom discussions that lead to new discoveries.

Activity suggestion

What is an ‘open-ended question’? Brainstorm a list of open-ended questions as a class and collect them in a ‘Curiosity Box’. Every Friday, choose one to ponder over the weekend. Children can then share individual discoveries during a ten-minute ‘reflection time’ on Monday mornings.

Exploration and discovery


Having asked her question and received five different answers, Koala is understandably confused. Which should she believe? It would be so easy for her to choose one of the answers as correct, based perhaps on which of her friends she trusts or likes the most. Alternatively, she could accept a mental image of a rainbow sea. Instead, she sets out to find out for herself. This conveys the message that active engagement is vital to critical thinking and helps children get beyond simple acceptance of information to form their own opinions and articulate their reasoning for those opinions.

Activity suggestion

Before reading, ask the class to turn to a partner and tell them what colour they think the sea is. Discuss the answers as a class – does everyone agree? Is there more than one opinion?

Analysing and explaining


Over the course of a day by the ocean, Koala realises that all her friends are in fact correct. In discovering this, she is learning two important facts. First, opinion is often based on experience and everyone’s experience may be different. Second, a question can have more than one answer. Koala then takes the next step in critical thinking – finding a way to explain what she has discovered. She picks up a shell and fills it with seawater so that she can show her friends how the sea changes colour over the day. Of course, in doing this she discovers a new fact and goes home happy in the knowledge that she has an answer all of her own.

Activity suggestion

What shape is water? Ask students to bring to class an empty clear container of any shape or size, e.g. a plastic or glass bottle, Tupperware container or plastic cup. Using a measuring jug, have students pour 250 ml of water into their container. Does the water look the same in every student’s container? Do some containers look fuller than others even though it’s the same amount of water? Why is that? What is a ‘liquid’ and how does it behave when poured into a container?

The role of the teacher


Every child needs a guide. In Koala’s case it is Boobook the owl. In true wise-old-owl fashion, Boobook does not give an answer to ease Koala’s confusion. On the contrary, she gives a cryptic response and prompts Koala to work it out for herself. She doesn’t offer to go with her, she doesn’t give suggestions on what she should look for, but simply urges Koala to visit the sea. The discovery is left entirely up to Koala. Allowing children time to work things through for themselves is a wonderful way to help children learn to think critically.

What Colour is the Sea? is available in all good bookstores and online. You can see sample pages here or listen to a podcast about picture books featuring Katie Stewart here. Free bookmarks, teaching notes, stickers and an at-home activity are also available for the book by emailing admin@fremantlepress.com.au. While stocks last. You can also download materials here and here.


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