Yeasts are one-celled micro-organisms. They consume oxygen and exhale carbon dioxide just like humans in a process called fermentation. The fermentation process is characterized by foaming and bubbling which helps for raising bread dough or making alcoholic beverages. Yeast cells digest food to get energy for growth. Their favorite food is sugar. If yeast cells receive enough food and air, and are at a comfortable temperature they grow very quickly. Yeasts can also break hydrogen peroxide down into water and oxygen gas. In this activity, you will investigate yeast activity in a cola, milk, and antacid (acidic, neutral, and basic mixtures). Rather than measuring carbon dioxide, however, you will use a Gas Pressure Sensor to measure the pressure caused by the production of oxygen gas when yeasts are added to hydrogen peroxide.
In this experiment, you will
Use a Gas Pressure Sensor and NXT to measure pressure in yeast mixtures.
Measure and compare yeast activity in acidic, neutral, and basic mixtures.
Make a conclusion about yeast activity.
Sensors and Equipment
This project/activity requires each of the following Vernier sensors and equipment (unless otherwise noted):