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 teachers of Chemistry have a unit on the topic of gases. And a large part of that unit is a discussion of the various gas laws. The numerical relationship between basic gas quantities - pressure, Kelvin temperature, volume, and the number of moles - is discussed and used to make predictions. This Concept Builder focuses on the relationship between gas pressure and Volume. The Concept Builder consists of 25 Questions that are organized into 10 Question Groups and spread across three distinctly different activities. The three activities can be described as follows:
 

• The Basic Relationship: Question Groups 1-3 ... Each question is a Multiple Choice question in which students must identify the basic nature of how pressure depends upon volume.
• Proportional Reasoning: Question Groups 4-9 ... Each question includes a table of pressure-volume data. Students must inspect the data and predict the effect that a doubling, tripling, or quadrupling of the volume has upon the pressure of a gas sample. 
• P-V Data: Question Groups 10 ... Each question includes a pressure-volume data table with several empty cells. Students must use the pressure-temperature relationship in order to determine the value of pressure, volume, or the P•V product for various states of the gas. A health bar monitors student understanding and terminates the activity when it appears students have a suitable understanding. Based on their understanding, students may have to complete 1-3 Data Tables before being rewarded the trophy for the activity.

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. So two side-by-side students are not likely to have the same question for question number three. And questions are organized into "groups" with questions within the same group being very similar (for instance, they may present different data to the student) but not identical.

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. 

In order to complete an activity, a student must correctly analyze each question for that activity. If a student's analysis is incorrect, then the student will have to correctly analyze the same or very similar question twice in order to successfully complete the activity. This approach provides the student extra practice on questions for which they exhibited difficulty. As a student progresses through an activity, a system of stars and other indicators are used to indicate progress on the activity. A star is an indicator of correctly analyzing the question. Once a star is earned, that question is removed from the que of questions to be analyzed. Each situation is color-coded with either a yellow or a red box. A red box indicates that the student has incorrectly analyzed the question and will have to correctly analyze it twice before earning a star. A yellow box is an indicator that the question must be correctly analyzed one time in order to earn a star. Once every question of a difficulty level has been analyzed, the student earns a Trophy which is displayed on the Main Menu. This system of stars and trophies allows a teacher to easily check-off student progress or offer credit for completing assigned difficulty levels.

The third activity - P-V Data - is quite different than most of our Concept Builder activities. This activity presents students with a table of data that has some empty cells. Students must complete the table. A health rating is used to determine the completion of the activity. There are four different tables. Students must complete a table with fewer than 20 misses in order to complete the activity. But after completing the third table, the student is automatically awarded the Trophy for the activity.

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.