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Systems and Scale | Activity 5.4

Activity 5.4: Explaining Other Examples of Combustion (50 min)

Students choose—or you choose for them—two examples of other fuels, then use the forms and procedures they used for ethanol to explain the combustion of those other fuels.

Resources Provided

Setup

Print enough copies of the three of 5.4 Other Organic Materials Readings and 5.4 Explaining Combustion Worksheets for each student to have one reading and the corresponding worksheet. In this activity, your students may use the Three Questions Explanations Checklist on the back of the Three Questions Handout. Be sure to have this available to students, and see the notes in the Modifications at the end of the Activity for ideas about how to use it.Prepare a computer and projector to display the PPT.

Directions

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

Assessment

Assessment takes place in Step 2 when you ask students to discuss the general characteristics of combustion of organic materials. At this point, students should articulate a general pattern of what happens when organic materials burn. Students should be able to articulate the patterns for each of the Three Questions at this point. You can review previous activities if this is difficult for students.

Assessment also takes place in Step 8. Listen to the ideas your students offer as they construct a class explanation for what happens when organic materials burn. Are they able to use precise language when describing atoms, molecules, bonds, and different forms of energy? Are they able to explain this at both macroscopic and atomic-molecular scales? Do they trace matter and energy through the chemical change? Use this conversation to determine if your students are prepared for the unit posttest, which takes place in the next activity.

Tips

Emphasize the similarities among the explanations of all organic materials burning. There are different fuel molecules, but the same kinds of atoms, bonds, reactions, and forms of energy. The same rules and patterns apply to all examples of burning organic materials.

Modifications

Have students select which fuel they would like to complete in step 4.

The checklist on the back of the Three Questions Handout can be used to scaffold students’ explanations in many ways.

  • Students refer to the checklist as they are constructing their explanations.
  • Students use the checklist as they are sharing and revising their explanations with a partner.
  • Students use the checklist to critique and revise their final explanations.
  • Students use the checklist to create and/or evaluate a whole-class consensus explanation.

We recommend using this checklist with a gradual release. As students improve in their ability to write their own explanations, they may rely on the checklist less.

Extending the Learning

Have students read the articles and/or watch the videos listed in the Digging Deeper section of the 5.4 Other Organic Materials Readings.

Have students construct a model that shows the combustion of other materials with the molecular models, and use those models to write balanced chemical equations. Have students explain combustion of other organic materials that they choose. They can find structural formulas for many organic materials on the Internet.