Changing the Density of a Liquid: Adding Salt

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Learners see that a carrot slice sinks in fresh water and floats in saltwater. Considering the placement of the carrot slice in water and saltwater, learners infer that the density of salt water must be greater than the density of fresh water. As a challenge, learners adjust the density of the saltwater until they get the carrot slice to hover somewhere in the middle of the cup. [Activity is publicly available through a web crawler capture on Activity write-up only, images are unavailable.]

Quick Guide

Preparation Time:
5 to 10 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
1 cent - $1 per group of students

Age Range:
Ages 8 - 14

Resource Types:
Activity, Demonstration, Experiment/Lab Activity, Lesson/Lesson Plan


Materials List (per group of students)


  • Physical Sciences
    • Chemistry
      • Solutions
    • Structure and Properties of Matter
      • Volume and Density
  • The Nature of Science
    • The Scientific Process
      • Asking Questions
      • Conducting Investigations
      • Gathering Data

Informal Categories

  • Food and Cooking


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access


  • Kessler, James H. ; Galvan, Patricia M.


  • All rights reserved, American Chemical Society, 2007