Grade Levels: 3-5, 6-8, 9-12

This lesson plan accompanies Virtual Labs: Understanding Water Activity, which is adaptable for grades 4-12. This interactive labs prompts students to explore how water acts inside food and how this affects spoilage.

Lesson Plan Common Core State Standards Alignments

Students will:

  1. Explore food science lab equipment and standard techniques.
  2. Participate in a virtual lab to test water activity in food.
  3. Explain why some items that seem to have a high moisture content do not spoil easily.


  • Computers with internet access
  • Interactive whiteboard


This lesson features an interactive, virtual lab titled Understanding Water Activity developed by our partner New Mexico State University (NMSU). Students learn about food science lab equipment and standard techniques for measuring water activity. The interactive animation guides students through both theory and practice, preparing them for experiences in a real lab.

The lab reinforces students' understanding that all living things need water to survive, and enzymes and chemical reactions also require water. If water activity is less than 0.6, almost all microbes, including bacteria, molds, and yeasts, stop growing. This means you can preserve food against spoilage by lowering its water activity–either by evaporating water away or binding it up.

Lesson Procedure:

  1. Tap prior knowledge by asking students what 10 foods they would bring on an extended camping trip into the woods. Provide time for students to discuss with a partner.
  2. Ask students to share what provisions they made for food. Which food items would last the longest without spoiling? Why? Explain that moist foods–like fresh fruit or raw meat–often have high water activity and spoil quickly. But some foods that seem moist–like jam or pepperoni–don’t spoil as quickly. Ask students why this is.
  3. Introduce the concept of food preservation and drying by projecting the Understanding Water Activity virtual lab for the class to see. Have student volunteers complete the first part of the interactive as you help them make connections to prior learning and learn how to utilize the interactive.
  4. Provide 10-15 minutes for students to complete the virtual lab on their own computer. Alternatively, you can have students work with a partner.
  5. Divide the class into teams and project the game quiz for them to see. Have teams compete to see which team can get the most answers correct. Address any misconceptions students have about water activity.
  6. Have students return to the list of foods they chose to take on their camping trip. Are there any items they might want to switch out, based on what they learned through the lab?
  7. If you have access to a water activity measuring instrument, allow students to test out their ideas and determine the water activity in the items they chose.

Extension Activities:

Extend student learning with the Virtual Labs Lesson Plan: Controlling Water Activity in Food. Be sure to explore other Virtual Labs games.