Teachers Parents Students

Carbon Dioxide Output You Can See

| 1 Comment
maddy-respirometer.jpg
Respirometer made from a water bottle and used in "The Effect of Exercise: Changes in Carbon Dioxide (CO2) Output" project.

[Editor's Note: Madeline Sides, 2010 Intel ISEF participant, has been testing project ideas this summer from the Science Buddies library of 1000+ science projects.]

It sometimes seems like movies and books tell us that, in life, one has to choose between being the jock or the brain, the football star or the mathematician. Hopefully, most of us grow up knowing that doesn't have to be the case and that academics and sports are not mutually exclusive. In high school, I participated in science competitions and earned varsity letters in two sports because I didn't want to be involved in just one or the other!


One of the science projects I tested recently as part of my summer internship with Science Buddies was The Effect of Exercise: Changes in Carbon Dioxide (CO2) Output (Difficulty: 6-8).

In bringing together chemistry and exercise physiology, this project highlights the relationship between science and sports and exercise. As an athlete and as a developing scientist, I really enjoyed this human biology project!

As part of this project, you construct a homemade respirometer, a device that measures the amount of CO2 a human produces when breathing. This respirometer utilizes a "colorimetric pH test" to measure CO2 production. Thanks to a pH indicator solution that changes color as CO2 is blown into the solution (and lowers its pH), a test subject can actually observe his or her own CO2 production.

After a quick trip to the pet store for the pH indicator solution, some clear plastic tubing, and a small aquarium pump, I got to work assembling my respirometer using a recycled water bottle. In less than 30 minutes, my setup was complete.

I practiced blowing into the respirometer and measuring the amount of time it took the indicator solution to change from blue/green (meaning neutral, about pH 7) to light yellow (indicating a lower pH and more acidic water) because of the CO2 in my breath. After taking some "control" readings of my CO2 output before exercise, I was ready to see how the readings would change with an increase in activity. The project calls for either "moderate" activity for 10 minutes or "brisk" activity for 2-3 minutes. I decided to exercise "briskly" by running and jumping around on my driveway, which probably gave my neighbors a good laugh.

After a few sessions of jumping around, breathing into my respirometer, monitoring the color change from blue to yellow, and comparing my exercise results to my resting control, I was able to draw some conclusions about how exercise affects CO2 output in humans.

I had fun, got a bit of a workout, and got the chance to turn chemistry into an athletic event—right there in the driveway!

~ Maddy


More Maddy


Madeline Sides has been testing project ideas this summer from the Science Buddies library of 1000+ science projects. If you missed her previous post, check out her experience measuring the amount of energy in common foods.




Science Buddies human biology and health project ideas are sponsored by Medtronic Foundation.




1 Comment

Hi everyone!!I love science...its my favorite subject!!!im in 6th grade at the moore heven elementary school.its fun being there.Im doing a science project on Leaves and Light.thats the name of it.Go animals and science...and music!!ha ha!!


katherine west

thumbnail
Egg science comes over-easy this time of year. Whether you are boiling eggs, dyeing eggs, or both, there are easy questions you can ask with your kids to turn the activity into a hands-on science experiment that everyone will enjoy....

thumbnail
This great guide and collection of family-friendly activities lets kids explore the history of robotics and put robotics engineering concepts to use with hands-on projects at home. Introduce Students to Robotics Engineering Robotics: DISCOVER THE SCIENCE AND TECHNOLOGY OF THE...

thumbnail
School and family science weekly spotlight: floating eggs.

thumbnail
There was no singular moment of Big Data Bang, but we are living in and heading towards a time of seemingly endless and exponential data explosion—and the race to create solutions and strategies to help tame, store, organize, and make...

thumbnail
Take a sneak peak at an exciting pair of hands-on science and engineering activities that Science Buddies has planned for USASEF visitors and get inspired to make your own robots this week in celebration of National Robotics Week—or experiment with your own catapult project!

thumbnail
Robotics engineers are experimenting with soft robots and robots modeled after biological organisms. With a squishy project at Science Buddies, students can get in on the action and test their own soft, air-powered, robot. A recent story in MIT News...



Your Science!
What will you explore for your science project this year? What is your favorite classroom science activity? Email us a short (one to three sentences) summary of your science project or teaching tip. You might end up featured in an upcoming Science Buddies newsletter!


Help With Your Science Project

The following popular posts are designed to help students at critical stages of the science project process.


You may print and distribute up to 200 copies of this document annually, at no charge, for personal and classroom educational use. When printing this document, you may NOT modify it in any way. For any other use, please contact Science Buddies.