If Hot Air Rises, Why is it Cold in the Mountains?

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This demonstration/activity helps learners understand why higher elevations are not always warm simply because "hot air rises." Learners use a tire pump to increase the pressure and temperature inside a plastic bottle. After the bottle cools to room temperature, learners will release the valve and observe cool air escaping the bottle. Learners will discover that as the air moves to lower pressure, it cools.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 8 - 18

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


Materials List (per group of students)

  • Two liter bottle
  • Tire valve to fit in a cap of bottle (Ace Hardware)
  • Bike pump with pressure gauge
  • LCD aquarium thermometer (Petco)


  • Earth and Space Science
    • Earth Structure
      • Atmosphere
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
      • Heat Transfer
      • Thermodynamics and Entropy
    • Energy
    • Motion and Forces
    • States of Matter
      • Gases
    • Structure and Properties of Matter
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Nature and Environment


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, Little Shop of Physics, 2009