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Yeast and Carbon Dioxide

Time Frame:
1 class period that runs 60 minutes.

Group Size:
Small Groups


Students will model carbon cycle and the effects of human activities on the respiration of yeast.

Main Curriculum Tie:
Science - Biology
Standard 2 Objective 2

Describe the flow of energy and matter in cellular function.


  • student page (attached)
  • 150 mL Ehrlenmyer flask
  • thermometer
  • balance
  • 50 mL graduated cylinder
  • rapid rise yeast
  • sugar
  • water
  • heat source
  • one-holed #5 stopper
  • glass tube
  • plastic tubing
  • ring stand and clamp


Background For Teachers:
Safety Issues:
Dispense chemicals in small quantities, warn students not to get on skin, eyes, or eat them.

One class period (50 min.) and part of another

Instructional Procedures:

  1. Students need to work in groups of 2-4.
  2. Make the yeast solution by mixing 1 tsp yeast in 200 ml water. Expand this to fit the number of student groups you have. Each group will need 100 ml. The yeast should be started before class by adding a tablespoon of sugar to the mixture. It should sit for at least 15 minutes to activate the yeast.
  3. The day before the lab, have students choose the variable they will test and design their experiment. Have them write their hypothesis on the board and make sure it makes sense and that no two groups have the same one. That way, they will have plenty of time to do the lab the next day. Sample hypothesis:

    If we use 2 tsp sugar, then there will be more gas.
    If we use more yeast, then there will be more gas.
    If we raise the temperature to 40 C, then there will be more gas.
    If we donít add sugar, then there will be less gas.

Lesson Design by Jordan School District Teachers and Staff.

Utah LessonPlans

Created Date :
Nov 18 2014 12:07 PM