### Notes:

The Frequency and Period 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:

Many Physics courses will begin the topic of waves with a discussion of vibrational motion. The vibrations of a pendulum or a mass on a spring are common discussion points. The the concepts of frequency and period typically emerge during this time. Students have difficulty distinguishing these two concepts from one another. At both the conceptual and the numerical level, they are often confused. This Concept Builder targets this confusion, providing questions that bring the confusion to the surface.

There are three activities in the Concept Builder. The first activity deals with more basic defintion-style elements of the concepts of frequency and period. In addition to definitions, the unis of frequency and period are also presented to students. The second activity presents graphical representations and data sets to students and asks them to determine which case has the greatest frequency or the greatest period. The third activity presents numerical data - the number of vibrational cycles and the time - and asks students to calculate the period and the frequency.

While the Concept Builder was intended as an in-class activity, use of it with our Task Tracker system makes it very suitable for an out-of-class homework assignment. After some brief laboratory exposure (pendulums and masses on a spring are helpful here) and some discussion of the definition and meaning of frequency and period, accompanied by some guided practice with several examples, allow students to put the principles into practice by the completion of the exercise. Teachers using the Concept Builder with their classes should preview the activity (or view the Questions in the separate file) in order to judge which activities would be most appropriate for their students.  The three activities in this Concept Builder are summarized as follows:

• Two Truths and a Lie: Question Groups 1-6
• Case Studies: Question Groups 7-12
• Do the Math: Question Groups 13-18

In order to complete an activity, a student must correctly analyze each question in 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 level. 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 in an activity 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 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 a few resources at The Physics Classroom website that serve as very complementary supports for the Frequency and Period Concept Builder. These include:
The first page of Lesson 2 of the Vibration and Waves Chapter of the Tutorial is a perfect accompaniment to this Concept Builder.

Frequency and Period

• Physics Interactives: Mass on a Spring Simulation
This simulation consists of a virtual spring and a mass set. Masses can be "lifted" and placed upon the spring, setting it into vibrational motion. A plot of position as a function of time is shown. The plot can be used to determine the frequency and the period. The simulation is accompanied by a ready-to-use activity that focuses on the factors that affect the frequency and the period of a vibrating mass on a spring.

Visit Mass on a Spring Simulation

• Science Reasoning Center: Waves
Our Science Reasoning Center consists of a collection of data-rich reading passages that focus on a phenomenon and present questions that target student ability to analyze data and draw conclusions. There are two passages that are relevant to the topic of frequency and period. They make great follow-ups to lab activities.

Visit Period of a Pendulum

Visit Mass on a Spring

• 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 WM1 and WM2 of the Wave Motion module provide great complements 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 Wave Motion module can be found on Part 5 of the six-part App series. Visit Minds On Physics the App.

• Curriculum/Practice: There is at least one Concept Development worksheet at the Curriculum Corner will be very useful in assisting students in cultivating their understanding, most notably ...

Describing Waves

Visit the Curriculum Corner - Wave Basics

• Calculator Pad: Wave Basics Problem Set: Our Calculator Pad consists of problems sets with 25-35 problems. Each problem is accompanied by an answer and an audio-guided solution.

Visit Wave Basics Problem Set

Additional resources and ideas for incorporating this Frequency and Period Concept Builder into an instructional unit on Vibrations and Waves can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.