1. Plants Unit Activity 3.4PT Observing Plants’ Mass Changes, Part 2
Carbon: Transformations in Matter and Energy
Environmental Literacy Project Michigan State University
Plants Unit Activity 3.4PT Observing Plants’ Mass Changes, Part 2

2. Plants Unit Map You are here (down the triangle) Application
Lesson 2: Foundations: Zooming into Organisms
Lessons 4 & 5: Explaining How Plants Make Food, Move, Function, and Grow
Lesson 3: Investigating Plants
Lesson 1: Pretest and Expressing Ideas
Lesson 1: Pretest and Initial Ideas
Lesson 6: Explaining Other Examples of Plant Growth and Functioning
Observations
Patterns
Models
Data from mass of plants growing from seed.
Data from plants in the light and dark with BTB.
Plants gain mass (more).
Soil loses mass (less).
Plants take in CO2 in the light.
Plants release CO2 in the dark.
Photosynthesis
Biosynthesis
Cellular Respiration
Pre Lesson: Investigation Set-Up
(up the triangle)
Inquiry
Evidence-Based Arguments
Model
(down the triangle)
Application
Observe
Coach
Use the instructional model to show students where they are in the course of the unit.
Show slide 2 of the 3.4PT Observing Plants’ Mass Changes, Part 2 PPT.
Pre Lesson
Pretest
Establish the Problem
Found-ational
Knowl-edge and Practice
Predict & Express Ideas
Fade
Post test
Maintain
Next Unit

3. Complete the Observing Plants’ Mass Changes Worksheet to organize your experimental data
Compile data
Following the directions in Part C on the students’ worksheet, have students fill in the data table, showing slide 3 of the 5.1PT Observing Plants’ Mass Changes, Part 2 PPT.
Have students record their data on their worksheets and follow the rest of the instructions on the worksheet to fill in their data table.

4. Class data for plants’ mass changes investigation
Have students compare data between groups and look for patterns.
Have students select a recorder to input their group’s results on the 5.1 Observing Plants’ Mass Changes Class Results 11 x 17 Poster. Lead a discussion to help students compare results across groups and identify patterns in the data.
Use Slide 4 of the PPT to guide students through data recording.
Have students compare the dry mass change of the plant with the dry mass change of the paper towel.
Show students slide 5 of the PPT. Have students discuss whether the patterns they observe in the class data match with their predictions.
Discuss any outliers or unexplained data points.

5. Comparing group results
What patterns are there in measurements made by all the groups?
Do the patterns match your predictions?
Have students compare data between groups and look for patterns.
Have students select a recorder to input their group’s results on the 5.1 Observing Plants’ Mass Changes Class Results 11 x 17 Poster. Lead a discussion to help students compare results across groups and identify patterns in the data.
Use Slide 4 of the PPT to guide students through data recording.
Have students compare the dry mass change of the plant with the dry mass change of the paper towel.
Show students slide 5 of the PPT. Have students discuss whether the patterns they observe in the class data match with their predictions.
Discuss any outliers or unexplained data points.

6. Plant mass change investigation results from Ms. A’s class
Group
Starting Mass of Radish Seeds (grams)
End Dry Mass of Plant Material (grams)
Change in mass of Radishes (grams)
Starting Mass of Paper Towel (grams)
End Dry Mass of Paper Towel (grams)
Change in Mass of Paper Towel (grams) 1
0.20
1.04 
0.84
4.01 
4.03 
0.02  2
0.22
1.06
0.84 
3.22
3.48 
0.26  3
1.39 
1.19
3.20
3.37 
0.16  4
0.16
1.30
1.14 
3.21
3.28 
0.07  5
0.21
0.86 
0.65 
2.77
2.89 
0.12 6
0.28
0.43 
0.15 
3.46
3.47 
0.01  7
0.25
0.54 
0.29 
3.30
3.35 
0.05 
Average
0.95 
0.73
3.31 
3.41
0.10
Have students compare their class’s data with data from another class to identify patterns.
Show students slide 6 from the PPT and ask them to compare their results to Ms. A’s class results.
Ask students if they recognize similar patterns from their own data. Use the poster to compare. What similarities or differences do they notice? What patterns do they see?
Probe student thinking with questions such as, Where did this mass come from? Did the mass come from the gel? What evidence do we have to build our conclusions?
Use slide 7 to discuss the idea that they know from this investigation that the majority of the mass of the plant did not come from the paper towel, so the mass must come either from air or from water. An unknown question is, does water or air make up the mass of the dried plants? Students may have some ideas about where this mass came from. Tell students that you will discuss where this mass came from later in this Lesson.

7. Have students compare their class’s data with data from another class to identify patterns.
Show students slide 6 from the PPT and ask them to compare their results to Ms. A’s class results.
Ask students if they recognize similar patterns from their own data. Use the poster to compare. What similarities or differences do they notice? What patterns do they see?
Probe student thinking with questions such as, Where did this mass come from? Did the mass come from the gel? What evidence do we have to build our conclusions?
Use slide 7 to discuss the idea that they know from this investigation that the majority of the mass of the plant did not come from the paper towel, so the mass must come either from air or from water. An unknown question is, does water or air make up the mass of the dried plants? Students may have some ideas about where this mass came from. Tell students that you will discuss where this mass came from later in this Lesson.

8. Examining group results
Examining results for mass changes
How are the mass changes connected with The Movement Question: Where are atoms moving?
What unanswered questions do you have?
Have students complete Part D of their worksheet.
Use slide 8 and Part D of the worksheet to help students describe the patterns they observed during the observation.
Help students to recognize that the mass changes provide them with evidence that much of the plant’s mass is coming from a source other than the medium in which it is growing. However, this evidence does not show where this mass is coming from.
Revisit predictions from earlier.
Ask students to retrieve their completed tools from the 3.1PT Predictions Tool for Plant Investigations. Have them compare the predictions they made with the results of the investigation. Which predictions were correct? Which predictions were incorrect? What questions do they still need to answer?