Activity 3.4PT: Observing Plants’ Mass Changes, Part 2 (45 min)

Target Student Performance

Students measure the dry weight of harvested plants and of paper towels or gel, identify patterns in data, and reach consensus with other groups about their results.

Resources You Provide

Resources Provided


By the time you are completing this Activity, your plants and paper towel should be completely dried out.

Print the 3.4PT Observing Plants’ Mass Changes Class Results 11 x 17 Poster before class. Your students will also need their copies of the worksheets they completed in Pre-Activity 0.2PT, Activity 3.1, and Activity 3.2PT. Print one copy of 3.4PT Observing Plants’ Mass Changes, Part 2 Worksheet for each student. Prepare a computer with a projector to display the PPT.


1. Use the instructional model to show students where they are in the course of the unit.


  • Use the class discussion to interpret how successful your students are at identifying patterns in the class data. Use the 3.4PT Grading the Observing Plants’ Mass Changes, Part 2 Worksheet to determine if your students had any trouble with data collection.
  • During this activity, note students’ success in measuring changes in mass. Also note students’ ability to reach a consensus about patterns in data and how they interpret results.
  • The discussions in steps 4 and 5 can be helpful for informal assessment in two ways: 1) It can help you assess your students’ skills in identifying sources of error and finding patterns in data, and 2) it can help you assess how well students identify the limits of the evidence. Do they recognize that the investigation does not fully answer the Matter Change Question?


  • Be sure to collect results from the different groups and compare their measurements. Discuss threats to accuracy of measurement.
  • Check to see if students can identify unanswered questions from the investigation.

  • Strategic grouping with strong speakers 
  • Compare class data orally and on the spreadsheet
  • Think-Pair-Share about the class data in comparison to another class’ data
Extending the Learning
  • Have students make predictions and design investigations to see how the results of the investigation would change if they used different types of plants.