Salt 'n Lighter

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In this activity, learners discover that as the salinity of water increases, the density increases as well. Learners prove this by attempting to float fresh eggs in saltwater and freshwater. This resource explains the relationship between water density and salinity as well as how this phenomenon relates to water displacement. It also explains how large ships float on water and includes a chart of some famous historical ship sizes. This resource also includes the flood safety tip "Turn Around, Don't Drown."

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
5 to 10 minutes

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

Age Range:
Ages 6 - 14

Resource Types:
Activity, Demonstration, Lesson/Lesson Plan


Materials List (per group of students)

  • 3 fresh eggs
  • 3 - 1.5 liter beakers (or quart jars)
  • 6 ounces of salt


  • Earth and Space Science
    • Earth Processes
      • Weather and Climate
    • Earth Structure
      • Oceans and Water
  • Engineering and Technology
    • Engineering
      • Transportation Engineering
  • Physical Sciences
    • Chemistry
      • Solutions
    • States of Matter
      • Liquids
    • Structure and Properties of Matter
      • Mass and Weight
      • Volume and Density
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Food and Cooking
  • Nature and Environment
  • Science Festivals Activity
  • Transportation


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



  • All rights reserved, National Weather Service,