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Systems and Scale | Lesson 1 - Pretest and Expressing Ideas

Lesson 1: Pretest and Expressing Ideas

Students complete the unit pretest, observe a demonstration of burning ethanol, and use the Expressing Ideas Tool to document their ideas about what happens when ethanol burns.

Guiding Question

What happens to ethanol when it burns?

Activities in this Lesson 

  • Activity 1.1: Systems and Scale Unit Pretest (20 min)
  • Activity 1.2: Expressing Ideas about Burning Ethanol (40 min)


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

NGSS Performance Expectations

This lesson helps prepare students to meet the NGSS performance expectations, but does not feature a mastery of any of them.

Background Information

Lesson 1 is designed to (a) help students to anticipate and begin thinking about the questions that they will answer about burning ethanol, and (b) help you as a teacher see how your students reason about matter and energy in the context of the first carbon-transforming process, combustion. In the Instructional Model, Activities 1.1 and 1.2 in this lesson serve to “Establish the Problem” for the entire Systems and Scale 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 Powers of Ten and the Three Questions) rather than chemical structures. Your students’ responses will also provide a starting point for discussions that take place later in the unit.

In Activity 1.2, students use the first process tool of the unit (Expressing Ideas) to document their thinking about what happens when ethanol burns. This phase of the unit should be treated like a brainstorming and elicitation session: the goal is to get students to express a wide range of ideas, even if they are incorrect. Ideally, students will come to recognize that they have many different ideas about what happens when ethanol burns, as well as unanswered questions. At this point in the unit, we expect many students to express Level 2 or Level 3 ideas: gas has no mass, ethanol disappears after it burns, and matter and energy are the same. We recommend using the pretest as well as the Expressing Ideas Tool to gauge how your students are thinking about matter and energy at different scales in the context of combustion.

Key carbon-transforming processes: Combustion

Lesson Map:

See the Systems and Scale Unit Read Me document for more details.

Unit Map for Lesson 1

Unit Map


Unit Map for Lesson 1

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