Plant Growth and Gas Exchange
Note: All teaching materials are packaged as ZIP file. You can download individual file from the following paragraphs, or download the whole package here. (Package)
Target Grades: 6-12 (w/ suggested modifications for tailoring to the level of your students)
Description: The activities in this unit engage students in collecting data about plant growth and gas exchange, then in developing a scientific explanation for their observations. A major focus of the unit is to engage students in the question of where the dry plant matter came from (i.e., not from the soil or water, but from the air), and what plant matter is (it is based on carbon). These activities will lay a foundation for tracing carbon through organisms and ecosystems, improving student understanding of the global carbon cycle.
Learning Goals: This unit is designed to help students make the connections described above by engaging them in two kinds of practices:
1. Inquiry or investigating practices, in which students learn to:
a) Make careful measurements of plants’ dry weight or biomass and gas exchange (absorbing and releasing carbon dioxide) in light and dark conditions, and
b) Construct arguments from evidence about how plants grow and exchange gases with their environment, and how growth and gas exchange are related.
2. Accounts or explaining and predicting practices. This unit addresses five different aspects of explaining and predicting plants’ growth and gas exchange. Two are core goals of this unit. They are:
a) Identifying reactants and products of the key carbon-transforming
b) Processes in plants: photosynthesis, biosynthesis, and cellular respiration..
Three other explaining and predicting practices are less central. They are:
3. Explaining photosynthesis, biosynthesis, and cellular respiration using atomic-molecular theory
4. Explaining energy transformations in photosynthesis, biosynthesis, and cellular respiration
5. Locating photosynthesis, biosynthesis, and cellular respiration in the general carbon cycle
Lesson Plans: These documents contain teacher instructions and student worksheets for all of the lessons in this unit. Teacher guide(download: word, PDF), Student Activities (download: Word , PDF), Student Readings (download: Word , PDF)
Powers of 10 Poster (download) – Chart containing notations for spatial scales from 10-10 to 105 meters, with areas for the four ‘benchmark’ scales (atomic-molecular, microscopic, macroscopic and large-scale) color-coded. This simple tool can be used to discuss the relative sizes of nearly any object that you might discuss in your courses, even outside of this unit.
Process Tool Poster (download) – Blank version of the mass-and-energy-tracing ‘process tool,’ which scaffolds for students the transformations of matter and energy that occur during biological (or other) processes, such as those discussed in this unit. Use in conjunction with sticky notes or magnets whenever you would like your students to be explicit about transformations in a given process.
Powers of 10 (General) (download) – A slideshow for use with Lesson 2; moves students from the scale of the whole earth to a single carbon atom.
Powers of 10 (Animated answers) (download) – For use with Lesson 3; single slide with animation that brings in all of the powers of 10 cards in this lesson to their proper places on the chart (i.e.- an answer key).
Powers of 10 (Air) (download) and Powers of 10 (Plant) (download) – Slideshows for use with Lesson 4; they move students through a subset of the powers of 10 to focus more directly on the structure of both air and plants. This introduction can then help students to make sense of the explanations that their observations in the upcoming activities will be pointing them towards. (Note: this animation--air molecule movement (download) is necessary for the final slide on the ‘air’ slideshow to work correctly)
Weight Gain and Los (download) – Slideshow for use with Lesson 5; guides students through the process and rationale for tracing wet and dry biomass separately.
Plants & Photosynthesis (download) and Plants & Respiration (download) – Slideshows for use with Lesson 8; these build off of the ‘plant’ slideshow used in Lesson 4 to focus students on the structures that allow plants to undergo photosynthesis and respiration. Depending on the level of your students, more or less detailed information can be presented here. Both slideshows also have an animation that you will need at one point (photosynthesis video (download), Cell Respiration(download).
Tracing Matter (download) – Slideshow for use in both Lessons 10 & 11; slides for lesson 10 can be used for class discussions of photosynthesis, biosynthesis and respiration. Those for lesson 11 include a simple terrestrial carbon cycle.
Assessments – Please plan to do the pre-test within 2 weeks of starting the lessons and post-tests within 2 weeks of ending the lesson. The pre and post test forms are the same.
Unit Feedback Form –The Environmental Literacy Math Science Partnership is funded by the National Science Foundation to conduct research on student understanding of carbon cycling, among other topics. This activity was carefully designed to increase student knowledge, understanding and skills. We are collecting pre- and post-test data from students. In order to make proper inferences about student learning, we need to understand what actually happened in each classroom. In order to make our teaching materials easier to use in the future, we also need teacher feedback. Please fill out this form ( download) and return it to your MSP contact.
For all other teachers, contact email@example.com a week or more before you want your students to take assessments so that she can enter your class into the on-line system.
Instructions for having your students use the on-line system (this is much preferred over paper and pencil versions. We can analyze this data faster and provide feedback to you sooner.)
· Paper and pencil versions (only use if you don’t have access to computers)
o Version A (randomly give half the students this form)
o Version B (randomly give half the students this form)