Teacher Guide
Unit A.1. Freezing Water. Students investigate why lake water freezes before saltwater. The scientific term is called "Freezing Point Depression." This phenomenon is used to study the structure of matter at the molecular level: NGSS PS-1A. Students will learn that particles of dissolved salt will intervene on the normal process of water freezing by preventing water molecules from forming hydrogen bonds at normal freezing temperatures. The purpose of this investigation is to introduce the processes of scientific investigation, scientific modeling and the scientific method. At the end of this unit, students should understand that models grow and change with increased knowledge. For that reason models can be thought of as initial models, working models, and final models. Students will also develop skills in independent research, using the Scientific Method, and collaboration. Students that earn an A will be able to draw a diagram that models the process of freezing point depression. Freezing point depression should never be explicitly taught until after the summative because it is the connection that students are being asked to make. If you teach it, then you are taking away the assessment tool: can students integrate new knowledge? Students who earn a B- or 80% will have completed 100% of their science notebook independently or with teacher help. Students who earn a C will have completed only 80% of their science notebook. Students who were not able to complete these requirements can earn a D by, independently or with help, graphing the data from lesson A.5. Graphing Data.
Unit A.1. Freezing Water. Students investigate why lake water freezes before saltwater. The scientific term is called "Freezing Point Depression." This phenomenon is used to study the structure of matter at the molecular level: NGSS PS-1A. Students will learn that particles of dissolved salt will intervene on the normal process of water freezing by preventing water molecules from forming hydrogen bonds at normal freezing temperatures. The purpose of this investigation is to introduce the processes of scientific investigation, scientific modeling and the scientific method. At the end of this unit, students should understand that models grow and change with increased knowledge. For that reason models can be thought of as initial models, working models, and final models. Students will also develop skills in independent research, using the Scientific Method, and collaboration. Students that earn an A will be able to draw a diagram that models the process of freezing point depression. Freezing point depression should never be explicitly taught until after the summative because it is the connection that students are being asked to make. If you teach it, then you are taking away the assessment tool: can students integrate new knowledge? Students who earn a B- or 80% will have completed 100% of their science notebook independently or with teacher help. Students who earn a C will have completed only 80% of their science notebook. Students who were not able to complete these requirements can earn a D by, independently or with help, graphing the data from lesson A.5. Graphing Data.