Lime water is used to test for carbon dioxide. Image  weebly.com

Lime water is used to test for carbon dioxide. Image weebly.com

ZIMSEC O Level Integrated Science Notes: Inhaled vs Exhaled air experiment: Method 1

Aim: Test to compare the composition of exhaled and inhaled air.

Materials: Limewater (to test for the presence of carbon dioxide), corks, test tubes, glassware tubing shown below

Method

Comparing Inhaled and exhaled air. Image credit pixshark.com

Comparing Inhaled and exhaled air. Image credit pixshark.com

  1. Set up the apparatus as shown above with an equal amount of lime water in each test tube.
  2. Breath in and out using the mouthpiece.
  3. Do this for a couple of minutes.

Results and explanation

  • Air enters through the left and out to the right.
  • The limewater in the right test tube turns milky.
  • This shows that exhaled air has more carbon dioxide when compared with inhaled air.
  • Limewater turns cloudy/milky when air containing carbon dioxide is blown into the test tube.

Conclusion

  • Exhaled air contains more carbon dioxide compared to inhaled air.

To access more topics go to the Integrated Science Notes page.

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