The Oxidation-Reduction Concept Builder is an adjustable-size file that displays nicely on smart phones, on tablets such as the iPad, on Chromebooks, and on laptops and desktops. The size of the Concept Builder can be scaled to fit the device that it is displayed on. The compatibility with smart phones, iPads, other tablets, and Chromebooks make it a perfect tool for use in a 1:1 classroom.


Teaching Ideas and Suggestions:

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. This Concept Builder is intended for the early stages of the unit, introducing students to the task of analyzing a redox reaction in order to determine the element that is oxidized and the element that is reduced. And finally, students must identify the oxidizing and reducing agents (last activity of three). There are a total of 57 questions organized into 15 Question Groups and spread across three unique activities. 

Here is the breakdown of the activities:
  • Two Truths and One Lie: Question Groups 1-3 ... Students are given three statements about oxidation-reduction reactions. One of the statements is false. They must identify the false statement. 
  • Redox Analysis 1: Question Groups 4-9 ... Students are given the balanced chemical equation for an oxidation-reduction reaction (a synthesis reaction). They must assign appropriate oxidation numbers to each element on the reactant and product side. Then they must identify the element that is oxidized and the element that is reduced.
  • Redox Analysis 2: Question Groups 10-15 ... Students are given the balanced chemical equation for an oxidation-reduction reaction. They must use oxidation numbers to identify the element that is oxidized and the element that is reduced and indicate how the oxidation state has changed (initial state and final state). Then they must identify the oxidizing agent and the reducing agent.

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. The first activity - Two Truths and One Lie - is very short and comprised of general knowledge questions. The Help Me! link would be a useful resource for students having difficulty with the meaning of the concepts. The second activity - Redox Analysis 1 - is comprised of two-part questions. First, students must assign oxidation numbers to each element. Once they have made correct assignments, they must identify the element being oxidized and the element being reduced. The third activity - Redox Analysis 2 - is comprised of questions that have three tasks: identify the elements being oxidized and reduced, identify the initial and final oxidation numbers of those elements, and identify the oxidizing and reducing agents.

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 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.