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Plants | Activity 3.1

Activity 3.1: Predictions about Plant Investigations (50 min)

Students use the Predictions Tool to record their predictions about what happens when plants are placed in the light and dark, and about where a plant’s mass comes from as it grows.

Materials You Provide

Resources Provided


This lesson helps students prepare for the Observing Plants in the Light and Dark investigation (Activity 3.2). An optional aid for this lesson is to have a ‘demo’ investigation setup to show students what they will be doing in the next lesson. If you chose to do this, see the materials list in Activity 3.2. Another optional extension to this lesson is for students to plan their own investigations. If you choose to do this, you may or may not want to have extras of the materials on hand in case groups of students want a closer look at their available materials. Optionally, print a few copies of the BTB Color Handout for students to use as a color reference.

Refer to the BTB Information and Instructions Handout for information about preparing BTB.

Prepare your computer, projector, and speakers for the Carbon TIME Growing Plants Video and the 2.1 Predictions about Plant Investigations PPT.

Print one copy per student of the 3.1 Predictions Tool for Plant Investigations (GL or PT). Prepare your computer, projector, and speakers for the Carbon TIME Growing Plants Video and the 3.1 Predictions about Radish Plants Growing PPT (GL or PT). Print one copy of the Three Questions 11 x 17 Poster and display it on your classroom wall. Print one copy of the Three Questions Handout for each student. Retrieve the materials from Activity 1.2. This may include a PPT slide from the lesson in which you typed students’ responses or a photograph of their sticky notes as well as the students’ completed 1.2 Expressing Ideas Tool for Plants Growing.


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

Show slide 2 of the 3.1 Predictions about Radish Plants Growing PPT (GL or PT).


During the class, listen to the ideas students offer in step 8 of the activity. Do students’ predictions follow the rules? At this point, do not correct student ideas, but listen for what they say about matter and energy in the context of plant growth. After class, use the 3.1 Assessing the Predictions Tool for Plant Investigations to compare your students’ work with what we would expect to see in Level 4 responses.

Ideally, the discussion about the Predictions Tool in this activity will reveal a range of student ideas. Some students will have Level 2 ideas with respect to the principles (matter and energy) and the context-specific knowledge (how a plant grows). Listen to see if students have a sense of necessity about connecting mass changes and movement of atoms, and if they recognize that if the plant gains mass, then atoms must be moving into the plant. Also, listen to see if students account for energy separately from matter (Levels 3 and 4), or if they suggest that some of the matter in the plants might be converted to energy (Levels 2 and 3). You do not need to correct any problems now; they will be addressed through the investigation and modeling in the activities to come.


  • Have a designated place in the classroom where students store their Expressing Ideas and Predictions Tools so they can easily refer back to their ideas at the end of the lesson.
  • Expect some students to make the right predictions for the wrong reasons. Note in particular whether they say that changes in the mass of the gel indicate that atoms are moving.


Document the thinking of the whole class on a large poster.

Extending the Learning

  • Have students plan and carry out their own investigations to answer the Three Questions. If groups get unreliable data, you may want to carry out the investigations as planned in this Unit, at least as a demonstration.
  • Have students review their notes about plant growth that they have been collecting since the Pre-Lesson. Discuss what is similar, different, or surprising about this method of growing plants compared to more familiar methods.