Notes

The concept of slope is an important concept in a Physics course. Data points from labs are often plotted and the task of determining the slope becomes vital to the completion of the lab and the accomplishment of the lab goal. This skill of calculating slope is one of those beginning-of-course skills that most teachers devote some attention to. While most of our Physics students have already learned how to calculate the slope of a line on a graph in a math class, they have a tendency to be a bit rusty and need a quick refresher of that skill. This Concept Builder is a tool to help students review and solidify their understanding of determining the slope of a line on a graph.

Teachers are encouraged to preview the activity (or view the Questions in the separate file) in order to judge which difficulty level(s) would be most appropriate for their students. Our summary of the three difficulty levels is as follows:

• Apprentice Difficulty Level: Questions 1-4 ... All graphs include lines with positive slope and y-intercepts of 0.
• Master Difficulty Level: Questions 5-8 ... All graphs include lines with positive slope; the y-intercepts are not 0.
• Wizard Difficulty Level: Questions 9-12 ... All graphs include lines with negative slope; the y-intercepts are not 0.

In order to complete a difficulty level, a student must correctly analyze each Question Group in that level. Each Question Group consists of two paired questions. The question that the student receives is chosen at random. If they miss the question, then they will receive the other question in the Question Group before receiving the missed question and second time. This approach provides the student extra practice on questions for which they exhibited difficulty. As a student progresses through a level, a system of stars and other indicators are used to indicate progress on the level. A star is an indicator of correctly analyzing the Question Group. 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 at a 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 levels.

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.

There are very few resources at The Physics Classroom website that pertain to the topic of experimentation and variables. What little discussion that is present is treated as more of an application in the understanding of other topics. Teachers will find that the most-related supports for the topic of variables and experiments are the other Concept Builders found in this same chapter of the Concept Builders section.