Science for Skills: Comparing Carbon Dioxide Levels in Inhaled and Exhaled Air

Key Concepts

• Objective: Compare the levels of carbon dioxide in inhaled and exhaled air using lime water.
• Lime Water: Used as an indicator for the presence of carbon dioxide. Turns from clear to milky when carbon dioxide is present.

Experiment Setup

• Materials Used:
  • Lime water
  • Two test tubes
  • Straws
  • Stoppers

Safety Precautions

• Wear goggles to protect your eyes while conducting the experiment.

Experiment Procedure

1. First Test Tube:

   • Exhale into a straw placed in lime water.
   • Observation: Lime water turns milky, indicating the presence of carbon dioxide in exhaled air.

2. Second Test Tube:

   • Inhale through a red straw which pulls air from outside through a blue straw and lime water.
   • Observation: Lime water remains clear, indicating less carbon dioxide in inhaled air.

Conclusion

• Result:
  • The lime water in the exhaled air test tube turns milky, confirming higher carbon dioxide levels in exhaled air.
  • The lime water in the inhaled air test tube stays clear, indicating lower carbon dioxide levels.
• Inference: There is more carbon dioxide in exhaled air than inhaled air.

Final Notes

• This experiment visually demonstrates the difference in carbon dioxide levels between inhaled and exhaled air using a simple setup.
• The change in lime water color is a clear indicator of carbon dioxide presence.

Enjoyed learning through this experiment and looking forward to the next episode!