What's In Your Breath?

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In this activity, learners test to see if carbon dioxide is present in the air we breathe in and out by using a detector made from red cabbage. Learners experiment by exposing the detector to air from a balloon filled by breath, a pump, or a carbon dioxide-producing mixture of baking soda and vinegar. Step-by-step instructions are included with photos. Activity guide includes a "What's going on?" explanation and connections to relevant science concept such as the composition of air we breathe, how alveoli in our lungs absorb oxygen and release carbon dioxide, and the negative effects of smoking and air pollution on our lungs.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
Over $20 per group of students

Age Range:
Ages 8 - adult

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • Leaf of red cabbage
  • 1 L of water
  • Blender
  • Liquid measuring cup or large container
  • Strainer
  • 4 large, clear drinking glasses or containers
  • Marker
  • Masking tape
  • 4 drinking straws
  • 3 large balloons (about 20-30 cm when inflated)
  • Ruler
  • Funnel
  • 25 ml (5 teaspoons) of baking soda
  • 60 ml (1/4 cup) of white vinegar
  • Empty soda or water bottle, approximately 500mL
  • Bicycle tire or balloon pump
  • Newspaper and/or paper towels
  • Rubber band (optional)


  • Earth and Space Science
    • Earth Structure
      • Atmosphere
  • Life Sciences
    • Ecology
      • Human Impact
    • Human Body
      • Health and Nutrition
      • Medicine
      • Respiration
  • Physical Sciences
    • Chemistry
      • Acids and Bases
      • Chemistry of Life


Learning styles supported:

  • Involves teamwork and communication skills
  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access


Source Collection

  • DIY Science Apps


  • , The Regents of the University of California, 2015

Funding Source:

  • National Institutes of Health Science Education Partnership Award, 5R25OD010543-02