Objective

By the end of this lesson, you will understand the role of yeast in the process of fermentation and be able to conduct a simple experiment to observe yeast activity.

Materials and Prep

• Active dry yeast
• Sugar
• Warm water
• Measuring spoons
• Small cups or containers
• Markers or labels
• Plastic wrap or balloons
• Optional: food coloring

Make sure you have read about yeast and its role in fermentation before starting the lesson. This will help you better understand the activities.

Activities

1. Mixing Yeast and Sugar

In a small cup, mix 1 teaspoon of yeast with 1 teaspoon of sugar. Add 2 tablespoons of warm water and stir well. Allow the mixture to sit undisturbed for about 10 minutes.

2. Observing Yeast Activity

After 10 minutes, observe the cup and note any changes. Look for bubbles or foam formation. You can also place a plastic wrap or balloon over the cup's opening and watch for it to inflate, indicating the release of carbon dioxide gas.

3. Optional: Adding Food Coloring

If you want to make the observation more visually interesting, add a few drops of food coloring to the yeast mixture before letting it sit. Observe any changes in color along with the other reactions.

Seventh Grade Talking Points

• "Yeast is a single-celled organism that belongs to the fungus kingdom."
• "Yeast plays a crucial role in the process of fermentation, where it converts sugars into alcohol and carbon dioxide gas."
• "Fermentation is used in various food and beverage production processes, such as making bread, beer, and wine."
• "When yeast consumes sugar, it produces carbon dioxide gas as a byproduct. This gas is what causes the bubbles and inflation we observed."
• "The warm water we used helped activate the yeast and speed up the fermentation process."
• "Food coloring can be added to the yeast mixture to make it easier to observe any color changes that may occur during fermentation."