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Crunch Time

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Crunch Time

In this quick and easy activity and/or demonstration, learners use two empty 2-liter bottles and hot tap water to illustrate the effect of heat on pressure. Learners will be surprised to see what happens to the bottles under different pressure conditions. This resource includes an explanation of how temperature affects pressure, how water pressure affects swimmers and whales differently, and how air pressure relates to thunderstorm safety.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
5 to 10 minutes

Estimated Materials Cost:

Age Range:
Ages 6 - 18

Resource Types:
Activity, Demonstration, Lesson/Lesson Plan


Materials List (per group of students)

  • Two empty 2-liter bottles
  • Hot tap water


  • Earth and Space Science
    • Earth Processes
      • Weather and Climate
    • Earth Structure
      • Atmosphere
  • Life Sciences
    • Diversity of Life
      • Animals
    • Human Body
      • Respiration
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
      • Thermodynamics and Entropy
    • Energy
    • Motion and Forces
      • Momentum and Velocity
    • States of Matter
      • Gases
    • Structure and Properties of Matter
      • Atomic Structure
      • Elementary Particles and Nuclear Physics
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Animals
  • Nature and Environment
  • Sports and Exercise


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,


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