### Notes:

The Work 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:

In the early stages of a unit on energy and energy conservation, it is typically a goal that the student be able to identify the presence or absence of work and its effect upon the mechanical energy of the object and the energy transformations that result from such work. The three activities in this Concept Builder target this learning goal. In each of the activities, students are presented with a collection of situations and must answer questions regarding the situation. In Activity 1 - Positive, Negative, or Zero Work, students must answer the question Is this an example of positive, negative, or zero work being done on the object?​ In Activity 2 - Gain or Loss, students must answer two questions: 1) What force is doing work upon the object? and 2) Does the total mechanical energy of the object increase, decrease, or remain the same as the result of this work? In activity 3 - Energy Transformation, students must answer the question What energy transformation best describes this situation?

This Concept Builder was intended as an in-class activity to be used in the early to middle stages of a unit on energy. Familiarity and understanding with the phrases positive work and negative work are pre-requisites to completion of Activity 1. Positive work occurs when there is a force applied in the direction of motion. Negative work occurs when there is a force applied opposite the direction of motion. In Activity 2, students should have some comfort with associating positive work with a gain of mechanical energy and negative work with a loss of mechanical energy. Familiarity and understanding of energy storage modes such as kinetic energy, gravitational potential energy, chemical energy, and disippated energy (thermal and sound energy) are pre-requisites to understanding Activity 3

The Concept Builder includes three activities. Teachers using the Concept Builder with their classes should preview the activites (or view the Questions in the separate file) in order to judge which levels would be most appropriate for their students. There is no redundancy from one activity to the next. They all fit together nicely to form a relatively thorough assessment of understanding of the work concept and its association with energy. At the same time, any one of the activities can be done at the exclusion of the others. Our summary of the three activities is as follows:

• Activity 1 - Positive, Negative or Zero Work: Question Groups 1-5. Five Question Groups are presented. Learners must determie whether the situation is describing an example of positive work, negative work, or zero work.
• Actvitiy 2 - Gain or Loss: Question Groups 6-9. Four Question Groups are presented. Learners must identify the force that is doing work and the effect of that force on the total mechanical energy (increase, decrease, or no change) of the object upon which the work is done.
• Activity 3: Energy Transformation: Question Groups 10-14. Five Question Groups are presented. A physical situation involving work is described and learners must determine the energy transformation that is associated with the described instance of work

We can imagine it being profitable to allow students to make judgements as to what level to begin with and to progress from easier to more difficult levels.

In order to complete an activity, a student must correctly analyze each question of 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 cue 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 an activity has been analyzed, the student earns a medal which is displayed on the Main Menu. This system of stars and medals allows a teacher to easily check-off student progress or offer credit for completing the activities.

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.

### Related Resources

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Work Concept Builder. These include:
• Minds On Physics Internet Modules:
The Minds On Physics Internet Modules include a collection of interactive questioning modules that help learners assess their understanding of physics concepts and solidify those understandings by answering questions that require higher-order thinking. Assignments WE1, WE2, WE3 and WE4 of the Work and Energy module provide great complements and extensions to this Concept Builder. They are best used in the middle to later stages of the learning cycle. Visit the Minds On Physics Internet Modules.

Users may find that the App version of Minds On Physics works best on their devices. The App Version can be found at the Minds On Physics the App section of our website. The Work and Energy module can be found on Part 3 of the six-part App series. Visit Minds On Physics the App.

• Physics Interactives:
The Physics Interactives section of our website include numerous interactive physics simulations that allow a student to visualize and explore various physical concepts. The Work and Energy chapter of the Physics Interactives includes several simulations that will serve as great extensions to this Concept Builder. Most simulations come with one or more Activity pages which are convenient for classroom use and utilize a guided inquiry approach to the use of the simulation. The following Interactives would be of interest to most teachers:

It's All Uphill

Stopping Distance

Roller Coaster Model

Work-Energy Bar Charts

Visit Physics Interactives

• Curriculum/Practice: Several Concept Development worksheets at the Curriculum Corner will be very useful in assisting students in cultivating their understanding, most notably ...

Work

Energy

Work-Energy Relationships

Work-Energy Calculations

Visit the Curriculum Corner - Work and Energy

Additional resources and ideas for incorporating Work into an instructional unit on Work and Energy can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.