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Plants | Lesson 1 - Pretest and Expressing Ideas

Lesson 1: Pretest and Expressing Ideas

In this lesson, students take a pretest and share their initial ideas about plant growth, identifying what plants need to grow and gain mass.

Guiding Question

How does a plant grow?

Activities in this Lesson

  • Activity 1.1: Plants Unit Pretest (20 min)
  • Activity 1.2: Expressing Ideas about How Plants Grow (30 min)


This lesson helps students start thinking about all of the unit objectives, but does not feature a mastery of any of them.

NGSS Performance Expectations

This lesson helps students start thinking about all of the unit NGSS Performance Expectations, but does not feature a mastery of any of them.

Background Information

The pretest and discussion in this lesson (a) help students to anticipate and begin thinking about the questions that they will answer in this lesson and (b) help you as a teacher see how your students reason about matter, energy and the carbon-transforming processes of photosynthesis, cellular respiration, and biosynthesis. In the Application activity Sequence, both Activity 1.1 and Activity 1.2 in this lesson serve as the “Establish the Problem” phase for all the activities in the Plants unit.

In Activity 1.1, the unit pretest is useful for two purposes. Your students’ responses will help you decide how much detail you want to include during the unit, particularly details about chemical structures of materials. If your students are mostly at Level 2 in the carbon learning progression, you may want to focus on the main ideas (like the tracing of matter and energy and the Three Questions) rather than chemical structures. Your students’ responses will also provide a starting point for discussions about the focus for this unit.

In Activity 1.2, through the discussion students will come to recognize that they have many different ideas about what how they think plants grow, as well as unanswered questions. We expect many students to express Level 2 or Level 3 ideas, for example, that plants grow because soil minerals coming into the plant through the roots provide energy for plant growth. Though most students will know that plants need light and that light is absorbed by the leaves, even students who know the word “photosynthesis” are likely to be vague about what happens during photosynthesis, particularly that photosynthesis enables plants to use CO2 as a carbon source for storing chemical energy and building plant tissues.

Key Carbon-Transforming Processes: Photosynthesis, Cellular Respiration, & Biosynthesis

Unit Map

Plants Lesson 1 Unit Map

Talk and Writing

At this stage in the unit, the students will be Expressing Ideas. The table below shows specific talk and writing goals for this phase of the unit.

Talk and Writing Goals for Expressing Ideas Phase

Teacher Talk Strategies that Support this Goal

Curriculum Components that Support this Goal

Treat this as brainstorming and elicitation.

Remember, there are no “right” answers at this point. We want to hear all ideas.

Unit Pretest

My Students’ Answers

Listen for ideas about what is happening to matter and energy at different scales.

Where did the energy come from?

Where does the matter go next?

Are you talking about matter or energy?

What about the atomic-molecular scale?

What about the cellular scale?

Unit Pretest

Expressing Ideas Process Tool

Listen for a wide range of student ideas. Press for more complete ideas.

Who can add to that?

What do you mean by _____? Say more.

So I think you said _____. Is that right?


Have students compare, contrast, and document their ideas.

Who has a different idea?

How are those ideas similar/different?

Who can rephrase ________’s idea?

Let’s record our ideas so we can come back to them and see how our ideas change.

Sticky notes on the class poster

Activity 1.2 Presentation

Encourage students to provide evidence for their ideas.

How do you know that?

What have you seen in the world that makes you think that?

Sticky notes on the class poster.