Build A Hydrometer

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In this activity, learners will explore how a hydrometer works by building a working model and conducting experiments. Using simple materials, learners will construct a hydrometer and then use it to compare the density of water before and after salt is added. This activity can work well as a demonstration with a large group or completed by individuals or small groups.

Quick Guide

Preparation Time:
Under 5 minutes
Learning Time:
45 to 60 minutes
Estimated Materials Cost:
1 cent - $1 per group of students
Age Range:
Ages 8 - 18
Resource Types:
Activity, Demonstration, Experiment/Lab Activity, Lesson/Lesson Plan, Model
Language:
English

Materials List (per group of students)

  • Milk carton or graduated cylinder
  • Clear plastic straw
  • Fresh water
  • Salt
  • Metric ruler
  • Permanent marker
  • Small lead sinker or BBs
  • Gum

Keywords

Subjects

  • Earth and Space Science
    • Earth Structure
      • Oceans and Water
  • Engineering and Technology
    • Engineering
      • Chemical Engineering
      • Mechanical Engineering
  • Mathematics
    • Algebra
      • Patterns
    • Data Analysis and Probability
      • Data Analysis
      • Data Collection
    • Measurement
  • Physical Sciences
    • Chemistry
      • Solutions
    • Motion and Forces
      • Gravity
    • States of Matter
      • Liquids
    • Structure and Properties of Matter
      • Volume and Density
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations

Informal Categories

  • Model Building

Audience

To use this activity, learners need to:

  • see
  • read
  • touch

Learning styles supported:

  • Involves hands-on or lab activities

Other

This resource is part of:

Access Rights:

  • Free access

By:

Source Collection

  • Association of Zoos and Aquariums

Rights:

  • All rights reserved, The Florida Aquarium, Inc., 2010