The Physics Classroom » Physics Interactives » Forces in 2D » Equilibrium » Teacher Notes

Notes:

The Balance It! Interactive 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 Interactive 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:

One of the most powerful tools of a Physics student is to think in terms of components. Understanding (and believing) that angled vectors can be replaced by two components - one along the x-axis and the other along the y-axis - can simplify most vector problems. After all, when all forces are up, down, right, and left, students generally find the problem to be easy. So the substituting of components for angled vectors is the first step of any two-dimensional analysis. By providing angled vectors on top of a background grid of squares, this Concept Builder quickly trains students to visualize components without needing to use a calculator. Students will quickly measure out squares along the x-axis and the y-axis from the origin out to the arrowhead of the vector. This, we hope, cultivates the habit of thinking in terms of components.

This Interactive consists of 20 difficulty levels. Each level includes a Question Group with three similar questions - essentially vectors lying in the same quadrant(s) but having different magnitudes and directions. Students will receive a random question from the group. If they miss the question, another question from the group will be given until they get a question correct.

While we "advertise 20 difficulty levels", there are really only five difficulty levels. Think of each row on the Main Menu as being a difficulty level. All questions in the same row are really of the same difficulty. The organization of levels and questions is better described as follows:
  • Levels 1-4: One angled vector is given.
  • Levels 5-8: One angled vector and one vector lying along an axis are given.
  • Levels 9-12: Two angled vectors are given.
  • Levels 13-16: Two angled vectors and one vector lying along an axis are given.
  • Levels 17-20: Three angled vectors are given.

Within each row, the Levels are scrambled. That is, one student's Level 1 might be another student's Level 3. And one student's Level 9 may be another student's Level 12. This random ordering of levels and of questions within Question Groups essentially guarantees that two side-by-side students are going to have a similar yet different user experience. It increases the amount of collaboration while decreasing the amount of copying.

The Interactive was designed to be used as an in-class activity somewhere in the middle of a learning cycle on forces at angles and equilibrium. After having developed the idea and having discussed force components, the Interactive makes for a great formative assessment. It can be done in pairs or small groups or individually. We recognize that teachers in different classrooms will need to have different expectations for how far students progress. Honors classrooms would likely be expected to more easily complete all 20 levels. Less able classes may only be asked to complete Levels 1-8. As we always do, we create resources with the intent that teachers will be able to adapt them to a wide variety of classroom situations.

The most valuable (and most overlooked) aspect of this Interactive is the Help Me! feature. The 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 page 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 page is in the section 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.


This Interactive is now available with Task Tracker compatibility. Learn more.
 



 
 

 

Related Resources

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Balance It! Interactive. 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 from the Forces in Two Dimensions module make for a great complement to this Concept Builder. They are best used in the middle to later stages of the learning cycle. We recommend missions F2D3 and F2D4 as accompaniments to this activity. 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 Forces in Two Dimensions module can be found on Part 2 of the six-part App series. Visit Minds On Physics the App.
     
 

Additional resources and ideas for incorporating the Balance It! Interactive into an instructional unit on Newton's Laws  can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.