Bubbling Plants Experiment to Quantify Photosynthesis

Overview

Students learn a simple technique for quantifying the amount of photosynthesis that occurs in a given period of time, using a common water plant (Elodea). They use this technique to compare the amounts of photosynthesis that occur under conditions of low and high light levels. Before they begin the experiment, however, students must come up with a well-worded hypothesis to be tested. After running the experiment, students pool their data to get a large sample size, determine the measures of central tendency of the class data, and then graph and interpret the results.

Engineering Connection

Students perform data analysis and reverse engineering to understand how photosynthesis works. Both are important aspects of being an engineer.

NGSS Alignment

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

• MS-LS1-6. Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
• 5-LS1-1. Support an argument that plants get the materials they need for growth chiefly from air and water.

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

Science & Engineering Practices	Disciplinary Core Ideas	Crosscutting Concepts
Constructing Explanations and Designing Solutions. Construct a scientific explanation based on valid and reliable evidence obtained from sources (including the students' own experiments) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future. Scientific Knowledge is Based on Empirical Evidence. Science knowledge is based upon logical connections between evidence and explanations. Engaging in Argument from Evidence. Support an argument with evidence, data, or a model.	LS1.C: Organization for Matter and Energy Flow in Organisms. Plants, algae (including phytoplankton), and many microorganisms use the energy from light to make sugars (food) from carbon dioxide from the atmosphere and water through the process of photosynthesis, which also releases oxygen. These sugars can be used immediately or stored for growth or later use. Plants acquire their material for growth chiefly from air and water. LPS3.D: Energy in Chemical Processes and Everyday Life. The chemical reaction by which plants produce complex food molecules (sugars) requires an energy input (i.e., from sunlight) to occur. In this reaction, carbon dioxide and water combine to form carbon-based organic molecules and release oxygen.	Energy and Matter. Within a natural system, the transfer of energy drives the motion and/or cycling of matter. Matter is transported into, out of, and within systems.