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.

Most Chemistry courses have a unit on electrochemistry or oxidation-reduction. One of the most important tools in such a unit is the table of Standard Reduction Potentials. Students often have difficulty using the table to answer questions. This Concept Builder is designed to build confidence in the use of the table. Students will use it to rank the strength of oxidizing and reducing agents and to identify substances that will serve to reduce or oxidize another substance. The Reduction Potential Concept Builder is comprised of 36 questions organized into 12 Question Groups and spread across three activities. The tasks required by the questions vary per activity.

Here is the breakdown of the activities:

• Ranking Tasks - Oxidizing Agents: Question Groups 1-3 ... Using a provided Reduction Potential table, rank three different oxidizing agents according to their strength.
• Ranking Tasks - Reducing Agents: Question Groups 4-6 ... Using a provided Reduction Potential table, rank three different reducing agents according to their strength.
• Agents for Hire: Question Groups 7-12 ... Identify those substances that are capable of oxidizing or reducing another substance. 

Teachers are encouraged to view the Questions or to do the Concept Builder in order to judge which activities are most appropriate for their classes. The three activities are scaffolded such that doing all three in order makes for an effective learning experience. 

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" of three; the question a student receives is selected at random. In the end, two side-by-side students will have quite different experiences.

For those with Task Tracker accounts, the Concept Builder also keeps track of student progress. It requires that students demonstrate a mastery of questions in each Question Group. If they miss a question from one group, then they will have to answer two consecutive questions correctly in order to demonstrate mastery. Progress is displayed in the progress report on the right side of the Concept Builder. A star indicates a demonstration of mastery. A question with a red background indicates that the student has missed the question. And a question with a yellow background means that the student must get one more question from that Question Group correctly answered in order to obtain a star. When an activity is completed, the student will be awarded a Trophy. This Trophy is displayed on the Main Menu screen. These strategies make the Concept Builder an ideal addition to the 1:1 classroom and other settings in which computers are readily available. 

The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each question group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise.