We're going to be honest: we do Physics. That's why this is called The Physics Classroom website. And when we do the Teacher's Notes section for our Concept Builders, we typically have a lot to say ... and a lot of resources to point you to. We're not claiming to be ignorant of chemistry; we just don't have a lot of resources here at The Physics Classroom to point you to. And so this page is going to be a lot shorter than our usual page that accompanies our Physics Concept Builders. That's our honest confession.
Constructing a galvanic cell diagram can be a daunting task for the beginning student of Chemistry. This Concept Builder will be a great pre-cursor to such diagramming as it provides 12 interactive questions in which students make decisions about the half-reactions, the anode and cathode location, and the direction of electron and ion flow. In each question, students are shown the redox reaction and the two half-cells. The components of the half-cells are labeled; the identity of the electrode and the aqueous ions are shown. Students tap on fields to complete the diagram. There are 7-8 fields per question.
There are a total of 24 questions in this Concept Builder. The questions have been organized into 12 Question Groups and spread across three difficulty levels. The levels are independent of one another, allowing a student to jump in at any level and to exit at any level.
Here is the breakdown of the difficulty levels:
- Apprentice Difficulty Level: Question Groups 1-4 ... Students are given contents of each half-cell and the balanced equation for the redox reaction. They must identify the half-equations, the anode and the cathode, and the direction of electron flow.
- Master Difficulty Level: Question Groups 5-8 ... Students are given contents of each half-cell and the balanced equation for the redox reaction. They must identify the half-equations, the anode and the cathode, the direction of electron flow, and the direction of positive/negative ion flow.
- Wizard Difficulty Level: Question Groups 9-12 ... Students are given contents of each half-cell and the balanced equation for the redox reaction. They must identify the half-equations, the anode and the cathode, the direction of electron flow, and the direction of positive/negative ion flow. Reactions are slightly more complex than the Master Level.
Teachers are encouraged to view the
Questions or to do the
Concept Builder in order to judge which difficulty levels and how many difficulty levels are most appropriate for their classes. The three difficulty levels are rather similar in difficulty. The Master and Wizard levels include an extra component - identifying the direction of ion flow through the porous membrane. For a student who knows the vocabulary and has a good sense for identifying the half-equations, the activity will go quite quickly. For those students who are progressing towards an understanding of the vocabulary and half-equations, the activity will be quite useful. The Help Me! button is recommended for those who are struggling. The questions can be viewed by logged-in teachers on a separate page. View
Questions.
There are 2 similar questions in every Question Group. The half-cells contain the same components but are simply reversed from left to right. If a student misses a question from within a particular Question Group, then they will have to answer both questions correctly (without any further miss). This strategy provides students extra practice on their most troublesome questions.
Like all our Concept Builders, this Concept Builder utilizes a variety of strategies to make each student's experience different. The ordering of questions is random. The Question number assigned to each question is scrambled. For instance, two side-by-side students will not have the same question for question number three. And questions are organized into "groups"; the question a student receives is selected at random. In the end, two side-by-side students will likely have quite different experiences.