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  • Floating and sinking may appear to be quite simple concepts. Something floats or it doesn’t – correct? What does floating mean? Does it have to sit on top of the water or can it be partially submerged? Do solid things float or do they have to be hollow? Does something have to be lightweight to float? What happens if something floats initially and then begins to sink once it becomes waterlogged?

    There are a lot of questions regarding floating and sinking. The science concepts that underpin whether an object floats or sinks – density, displacement and forces – are quite complex. Understanding these concepts and forming accurate conceptions requires time and multiple learning experiences. Experiencing, identifying and describing the patterns associated with this physical phenomenon feature in levels 1–5 of the New Zealand Curriculum.

    Use this activity prior to teaching about floating and sinking to gauge students’ thinking about why some things float or sink. Consider using this activity again – during the teaching process or at the end of a unit for formative assessment.

    In this activity, students use an interactive or paper-based graphic organiser to consider whether an object floats or sinks.

    By the end of this activity, students should be able to:

    • use their prior knowledge to make choices about whether an item floats or sinks
    • begin to use appropriate content vocabulary
    • begin to provide evidence to support their choices
    • discuss their ideas with others who may hold different views.

    Download the Word file (see link below).

    Related content

    The article Building Science Concepts: Floating and sinking has useful background information for educators.

    The PLD article Physical World – Floating and sinking curates Hub resources on this topic.

    A sinking feeling – this level 4 Connected article introduces the science concepts underpinning floating and sinking in the context of a boat race.

    Our Floating and sinking Pinterest board is full of related resources.

    Activity ideas

    These simple hands-on activities use exploration and play to observe and learn about the science concepts:

    Useful links

    Related Building Science Concepts books

      Published 11 October 2022 Referencing Hub articles
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