This activity turns a classic student observation activity of yeast generation of gas into a guided inquiry lab. Rather than give the students one sugar, we give them a range of foods to taste for developing hypotheses based upon their analyses of the foods. The students then design the experiment with appropriate controls and carry it out using gas generation in a closed system with balloons to measure yeast fermentation.

Learning Objectives

After completing this lesson, students will be able to do the following:
  1. Identify dependent and independent variables, as well as appropriate experimental controls.
  2. Use initial observations and prior knowledge to form a hypothesis.
  3. Explain the relationship between food and growth.


Science Standards

This lesson addresses National Science Education Standards (1996):
  • Science as Inquiry – Plan and Conduct a Simple Investigation 
  • Science as Inquiry – Employ Simple Equipment And Tools To Gather Data And Extend The Senses
  • Science as Inquiry – Use Data To Construct A Reasonable Explanation 
  • Science as Inquiry – Communicate Investigations and Explanations
  • Life Science – Organisms and Their Environments
  • Physical Science – Properties of Objects and Materials