What Do Enzymes in Pineapple Juice Do to Milk?

Overview

In this fun chemistry lesson, students will explore chemical reactions by mixing pineapple juice and milk. Students will observe whether the properties of milk change when it is mixed with pineapple juice, as well as how they change. They will then infer from their results whether a chemical reaction happened. In the process, they will not only learn about chemical reactions but also discover the importance of enzymes and their role in the human body.

NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:

• 5-PS1-4. Conduct an investigation to determine whether the mixing of two or more substances results in new substances.

This lesson focuses on these aspects of NGSS Three Dimensional Learning:

Science & Engineering Practices	Disciplinary Core Ideas	Crosscutting Concepts
Planning and Carrying Out Investigations. Conduct an investigation collaboratively to produce data to serve as the basis for evidence, using fair tests in which variables are controlled and the number of trials considered. Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon. Constructing Explanations and Designing Solutions. Use evidence (e.g., measurements, observations, patterns) to construct or support an explanation.	PS1.B: Chemical Reactions. When two or more different substances are mixed, a new substance with different properties may be formed.	Cause and Effect. Cause and effect relationships are routinely identified and used to explain change.

Materials

For preparation before class:

• Fresh and unpasteurized pineapple juice, such as the cold-pressed versions available at some stores.

or

• Pineapple (fresh or frozen)
• Paring knife
• Cutting board
• Food grater, juicer, or blender
• Cheesecloth or cotton fabric
• Microwave or stove
• Microwavable containers with lids (2)

For teachers:

• Fresh cow's milk, any percent but not evaporated (room temperature)
• Measuring spoons (tablespoon and teaspoon)
• Cottage cheese

For each student group:

• Mini cups, about 2 oz. (5)
• Spoon
• Permanent marker
• Paper towels