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  • In this activity, students investigate water density by floating eggs in freshwater and saltwater.

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

    • discuss the concept of density
    • discuss how salt increases the density of water
    • explain why an egg sinks in freshwater but floats when salt is added.

    Download the Word file for:

    • introduction/background notes
    • what you need
    • what to do
    • extension idea.

    Related content

    Explore the big ideas that underpin floating and sinking in the article Building Science Concepts: Floating and sinking.

    Read the articles Ocean salinity and Ocean density to learn about the vital role salinity and density play in ocean currents and heat circulation.

    Activity ideas

    Temperature, salinity and water density – use this activity to help your students visualise differences in water density.

    Buoyancy in water – students make a Cartesian diver to demonstrate the relationship between volume, mass and density.

    Investigating seawater – students investigate some of the properties of seawater.

      Published 4 September 2008, Updated 22 January 2014 Referencing Hub articles
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