This Concept Builder is intended for use in the middle to later stages of a learning cycle on mechanical energy conservation. There are three highly scaffolded difficulty levels involving an energy analysis of a vertically launched projectile. Students must determine values of PE and KE at various locations along the trajectory. The motion is entirely vertical; the upward path and downward path are offset horizontally for clarity purposed. In each case, the initial kinetic energy (at ground level) of the object is given. This kinetic energy value and height information are used to determine potential and kinetic energy at other locations. In the
Apprentice Difficulty Level, a background grid is used to determine PE values. The peak of the trajectory is 20 squares high. Other locations include the
half-way height(10 squares high) and either the
one-quarter height(5 squares high) or the
three-quarters height(15 squares high). In the
Master Difficulty Level, height values of three locations are given and used to determine the potential energy values. Energy conservation can be used to determine the kinetic energy values. In the
Wizard Difficulty Level, the locations to be examined are the peak location, the
half-way height, and either the
one-quarter height or the
three-quarters height. Students must use enery conservation to determine the PE and KE values and then calculate two height values and two speed values.
We recommend all three difficulty levels, beginning with the easiest. For purely conceptual physics classes, the Apprentice Level may be most suitable; the Master level might be a stretch for such classes. More advanced classes should find all three difficulty levels very do-able. Students will quickly gain an understanding that the PE and the height are directly related. You will need to prep students on how to use energy conservation to determine the PE and the KE values. And if doing the Wizard Difficulty Level, you will need to prepare students with a strategy for calculating speed values from KE values.
Student misses are tracked and use to determine a Health Rating. The Health Rating is published at the completion of the difficulty level. The formula for determining a Health Rating is shown
on a separate page. Students can repeat the exercise as many times as needed to improve their grade above a minimum-required level.
Task Tracker Note: as of this time, we do not collect information regarding the Health Penalty in our Task Tracker database.
This Concept Builder was intended as an in-class activity or as an assigned out-of-class activity for those classrooms subscribed to Task Tracker. After some lab work, some discussion of how to analyze energy values, and some guided practice, allow students to try it for themselves. Teachers using the Concept Builder with their classes should preview the activity (or view
the Questions in a separate file) in order to judge which difficulty levels would be most appropriate for their students.
Students can complete as much of the table as they wish before checking their answers. And they can check their answers as many times as they wish. Feedback regarding the correctness of their answers is immediate and provided using a color-coding system. Correct answers are displayed in a table cell with a green background; these correct answers become
locked and cannot be changed. Incorrect answers are displayed in a table cell with a red background. Each time students check their answers, the number of missed answers is determined. A running tally is kept of the number of misses. When a student accurately completes the table, a Health rating is displayed on the screen. The Health rating is dependent upon the number of misses. Formulas for computing the Health rating are discussed
on a separate page. The Health rating is also displayed on the Main Menu screen for any completed difficulty level. A student can always repeat a difficulty level in order to improve their Health rating for that level. The best Health rating is always displayed on the Main Menu screen below the trophy for that difficulty level.
We leave it to the discretion of individual teachers as to what they wish to do with the Health rating information. We recognize that there will be some teachers who feel most comfortable with their students in simply requiring that a difficulty level be completed and trophy be earned. Other teachers may wish to require completion of a difficulty level with a minimum Health rating. For instance, such teachers may require that each difficulty level be completed with a 70% or higher Health rating. Still other teachers may tie the Health rating into a grade or allow a homework pass for completing an activity that exceeds a 90% Health rating. Decisions as to what to do with the Health rating are best left for individual teachers who know their students the best.
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.