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

In this Virtual Labs lesson plan, which is adaptable for grades 4-12, students are introduced to water activity levels in food.

Lesson Plan Common Core State Standards Alignments

Students will:

  1. Explore food science lab equipment and standard techniques for measuring water activity.
  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.

Materials:

  • Computers with internet access for BrainPOP's GameUp

Preparation:

This lesson uses an online virtual lab that familiarizes students with food science lab equipment and standard techniques for measuring water activity. The interactive animation guides the user through both theory and practice, preparing them for experiences in a real lab.

The lab will reinforce students' knowledge 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 that food can be preserved against spoilage by lowering its water activity – whether by evaporating water away or binding it up.

After this lesson, we recommend extending student learning with the Virtual Labs Lesson Plan: Controlling Water Activity in Food.

Lesson Procedure:

  1. Hook students into the topic of water activity by asking them what 10 foods they would bring on an extended camping trip into the woods. Provide time for students to talk with a partner and brainstorm.
  2. Ask students to share what provisions they made for food. Which food items would last the longest without spoiling? Why? Students may mention 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. Why is this?
  3. Introduce the concept of food preservation and drying by projecting the Understanding Water Activity Interactive 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 interactive 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 students 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 decided to take on their fictional camping trip. Are there any items they might want to switch out, based on what they learned through the interactive?
  7. If you have access to a water activity measuring instrument, allow students to test our their ideas and determine the water activity in the items they chose.

Extension Activities:

After this lesson, we recommend extending student learning with the Virtual Labs Lesson Plan: Controlling Water Activity in Food. Be sure to check out the other Virtual Labs games on GameUp!
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