Teacher Notes for Waves and Sound

 

Lesson Plans || Learning Outcomes and Activities || Teacher Notes || Labs

 

Unit Overview

This is a LLLOOONNNGGG unit. It could easily be divided into two units - one on Vibrations and Waves and one on Sound and Music. We've put it all together and went light on the topic of vibrations. We propose 20 days, starting with the idea of a vibrating object, transitioning to the topic of wave motion and all that it entails, and then applying wave principles to an understanding of sound waves and music. We have packed this unit with Concept Builders (9), Minds On Physics missions (8), Simulations and Concept Checkers (4), CalcPad problem sets (5), Science Reasoning Center activities (2), and hands-on lab experiences (6). We've also included a project in the plans. We have scheduled two quizzes into the unit plan. You'll need to plan on an additional day for a unit test.


 

Awkward Terrain

We have always found this general area of physics a bit difficult to organize. When it comes to textbooks, there seems to be little agreement on how to organize the topics of vibrational motion, wave motion, sound waves, and light waves. In some textbooks (mostly college physics), there's an entire chapter on vibrational motion and other textbooks devote a page to it. Some textbooks have separate chapters for waves and sound and other textbooks append the sound wave ideas to the end of the Waves chapter. In our own development of the site, we have used a variety of organizational schemes. This wasn't really planned. In our early years, we just tended to group resources for multiple topics together under one larger heading because we didn't have enough to group them under a single topic heading. So if we had only one Sound Wave simulation, we would group it with our two Wave simulations and put it under the heading Waves and Sound. We did the same with Concept Builders and other sections. Then when our first vibrational motion Concept Builder came along, we put it in our Waves and Sound section. Then we created seven Concept Builders for pendulum motion and simple harmonic motion and decided to create a Vibrational Motion section. 

So there is a rhyme and reason to the apparent madness but what we really wanted to say is we apologize. Sorry. You may need to look in a few places to find everything you need when it comes to the topics of Vibrations, Waves, and Sound. There's quite a bit of this on the site. It's just organized a bit awkwardly. 




 

Labs

We have proposed six labs for this unit. Since two of these (Labs 1 and 4) do not have any Teacher's Guides available for comparable labs, we are supplying some notes here. Additional details are on our Lab Page for this unit. 

Lab 1: Lab 1 requires the use of two acrylic paint colors (red and blue recommended), string or rope to form a pendulum attached to the ceiling, a large funnel with rubber tubing attached to the nozzle and an adjustable tubing clamp to adjust the drip rate, butcher paper, a constant speed vehicle, stopwatches, masking tape, and protection from the inevitable mess that is about to come. Suspend the funnel filled with the acrylic paint from the ceiling by two strings so it swings as a pendulum; set it up to slowly drip paint onto butcher paper below. Pendulum frequency can be controlled by holding strings at a fixed height while it is swinging; maintain your grip. Start the pendulum swinging and pull paper with a constant speed vehicle. Dripped paint forms a wave. Do two trials - one with red paint and a long pendulum and another with blue paint and a short pendulum. Use a short enough pendulum (and long enough paper) to get >2 cycles minimum. Measure time for 2 cycles, length of repeating pattern, and (in a separate trial) speed of tractor, and (in still another trial) the time for the funnel to make 5 back and forth cycles of vibration. Plan for a mess. You do the messy part; hire a few assistants to make measurement, turn the vehicle on, and to do the timing. Plan for a WOW! Tape the butcher paper on the wall (if possible) for frequent reference during the unit.

Lab 2: Lab 2 is identical to a lab that we have used for our other courses. We have provided a link to the Teachers Guide on our Lab page.

Lab 3: Lab 3 is identical to a lab that we have used for our other courses. We have provided a link to the Teachers Guide on our Lab page.

Lab 4: Lab 4 requires the use of a tuning fork, rubber mallet or bridge (or soft sole of a shoe), a computer, a printer, and a computer-interfaced microphone. Students use the microphone to capture a short sample of sound from the vibrating tuning fork. Most software programs will display pressure as a function of time. Adjust the plot to show several (>10) pressure peaks. The plot can be printed or screen captured; it should be marked to show a count of the peaks from start (0) to some final peak (X). The times associated with the peaks should be likewise marked on the plot. Students should use X and ∆time to determine the frequency and the period. The frequency stamped on the tuning fork should also be reported.

Lab 5: Lab 5 is identical to a lab that we have used for our other courses. We have provided a link to the Teachers Guide on our Lab page.

Lab 6: Lab 6 is identical to a lab that we have used for our other courses. We have provided a link to the Teachers Guide on our Lab page.

 

The Calculator Pad (a.k.a., CalcPad)

The  Waves section and the Sound Waves section of our Calculator Pad includes 38 problem sets with well over 200 problems. We used this bank of problems to create five custom CalcPad problem sets for the Conceptual Physics course. Most of the problems in these problem sets were customized/adjusted versions of the original problems. We provided some scaffolding, added some hints, reduced some complexities associated with the language, and just generally softened the difficulty level to make the problems more approachable by this level of student.

But if you need more problems or problems with less scaffolding, you will find them among these 38 problem sets. And with a Task Tracker subscription and our directions and video walk-throughs, you can even create your own custom problem sets or edit one of ours. You will never find a shortage of available word problems in the CalcPad section.


 

Pan Flute Project

We scheduled two days for a project in which students Build and Tune a Pan Flute. This is a construction/build project that involves the use of Physics to determine the length of PVC tubes. The required materials include PVC tubing (1/2-inch inner diameter; 8-12 foot lengths), foam insulation (for insertion into the PBC tubes), PVC tube cutters, Sharpies to mark cut locations along the tube, hot glue and hot glue guns, and a means of determining the frequency of a sound (you can use our Spectrum Viewer). Find some short YouTube videos to show students that demonstrate the use of a Pan Flute to produce professional sounding music. Review closed-end resonance tube math. Emphasize safety when cutting the PVC tubes. An 8-foot length tube should be sufficient for a single lab group.

The steps of the project can be described as follows.
 

• Create a pan flute using 8 PVC tubes (closed at one end) that play frequencies of 523 Hz (C₅), 587 Hz (D₅), 659 Hz (E₅), 698 Hz (F₅), 784 Hz (G₅), 880 Hz (A₅), 988 Hz (B₅), and 1047 Hz (C₆). Assume v = 340 m/s.
• Calculate the L of closed-end air column to produce such frequencies; check calculations with teacher
• Add 1 cm to L to allow for insertion of foam plug to close off end; cut PVC tubes to length
• Insert foam piece; adjust location and measure frequency using a frequency meter like Spectrum Viewer (<== we have one!!)
• Use trial-and-error to get the frequency perfect; then use hot glue to seal location of foam piece
• Repeat for all 8 PVC tubes
• Assemble PVC tubes with open-ends flush to produce final instrument
• Look up some simple songs to play with C-D-E-F-G-A-B-C. Pick a song and practice playing the song.
• Perform your concert for your classmate  

 

Project Time?

Looking for a different project besides our Pan Flute Project? Maybe we can help. One of our more recent Interactives is Sound Spectrum Viewer. Sound Spectrum Viewer is a tool and not a simulation. It can be used to capture the sound spectrum from any source. The Interactive will graphically display information about the frequencies (and their amplitudes) over the course of time as a waterfall plot. The tool is also capable of displaying a Fast Fourier Transform (FFT) of the collected sound, making it a useful tool for analyzing the harmonics of musical instruments. It works well on computers, tablets, and phones. So if you have an idea for a project on sound, consider the use of our Sound Spectrum Viewer. Just give your device microphone a cleaning, visit the app, and start listening. Give your students a question to explore or let them come up with one of their own.



 

Science Reasoning Center

We have several Waves and Sound activities at our Science Reasoning Center. These provide a slightly different approach than Concept Builders or Minds On Physics. They tend to emphasize less conceptual development and more scientific processing, data interpretation, experimental analysis, etc. They often make great follow-ups to labs and can sometimes be used as an introduction to a topic. For most topics, they are great accompaniments to an NGSS curriculum. If you have a Task Tracker subscription, visit the Teacher Resources section in order to quickly preview the activity and navigate through all the questions. You will also find information there about NGSS alignments. Here are some of our favorites:
 

1. Wave Speed
   Information about three short student experiments are presented to students. Students analyze the design of the experiment, identify appropriate claims and the supporting evidence for such claims, and use the patterns in the data to predict the result of subsequent trials. The activity includes a wide collection of questions that target the HS-PS4-1 performance expectation of NGSS.
2. Slinky Experiments
   Students investigate experimental data to determine the nature of the speed-wavelength-frequency relationship for waves traveling in a uniform medium. Students plan an investigation to determine what variables do and don't affect the speed of a wave. And finally, students investigate the values of a wave from one medium to another to predict numerical values of wavelength and frequency.
3. Standing Waves on a Rope
   Questions target a student's ability to understand the design of an experiment; to combine results from two or more data presentations in order to draw appropriate conclusions; to interpolate and extrapolate from data in a table; to predict the results of an additional trial; to translate information from a data table to a graph; and to make predictions based upon a model.
4. Sound Intensity and the Decibel System
   Questions target a student's ability to identify and use the relationship between intensity and the deciBel rating; to read values from and to interpret a complex graph; to use data from two or more data presentations in order to compare two sounds; and to combine information from two or more data presentations in order to draw valid conclusions.
5. The Sound of Music
   Questions target a student's ability to select information from a complex data table or a graph; to identify the relationship among the variables wavelength, frequency, speed, and harmonic number; to use such relationships to make comparisons of the sounds produced by two different air columns; and to combine information in a table with information in a graph in order to identify appropriate conclusions.

 

Other Resources

There are a few resources that we did not list in our Lesson Plans and Learning Outcomes and Activities that you may find to be very helpful. These include:
 

1. Physics Interactives: The Particle Wave
   The Particle Wave simulation allows students to explore the nature and properties of a wave. Properties such as wavelength, amplitude, and speed can be changes. The effects of the change on the wave pattern and particle motion can be immediately observed. The simulation is accompanied by a Student Activity Sheet and a Concept Checker.
2. Minds On Physics: Mission WM8 - Mathematics of Standing Waves
   Students utilize a combination of textual information and diagrams to mathematically analyze standing wave patterns.
3. Minds On Physics: Mission WM2 - Wave Characteristics
4. Students describe the basic characteristics of waves such as frequency, wavelength, amplitude, period, and speed and utilize mathematical relationships related to wave characteristics
5. Minds On Physics: Mission WM3 - Wave Speed
   Students define wave speed, identify the variables that effect wave speed, and utilize the definition of wave speed to solve simple computational problems involving speed, distance and time.
6. Minds On Physics: Mission SM6 - Harmonics for String Instruments
   Students identify the standing wave patterns for stringed instruments and use them to state the length-wavelength relationships and identify the relationship between the frequencies of the various harmonics for stringed instruments.
7. Minds On Physics: Mission SM9 - Mathematics of Open-End Air Columns
   Students relate the wave speed, wave frequency, wavelength, and the length of an open-end air column for one of the harmonics.
8. Minds On Physics: Mission SM11 - Mathematics of Closed-End Air Columns
   Students relate the wave speed, wave frequency, wavelength, and the length of a closed-end air column for one of the harmonics.

 

Teacher Presentation Pack

Yes. This is going to cost you ... money. But it is also going to pay you back big time in return ... time and the satisfaction that comes with managing your class and providing engaging lessons. Our Teacher Presentation Pack was designed for all Physics teachers; but we particularly had early-career and cross-over Physics teachers in mind. For them (and anyone), this can be a huge time saver and a life saver (excuse the slight exaggeration). It includes a large collection of Slide Decks, Lesson Notes, animations, and graphics for use in your classroom. Once downloaded, you can modify and customize the Slide Decks as needed. The slides are highly organized and (mostly) graphical; they make great graphic organizers for any student, and especially for the struggling student. Learn more.


 

Also Available ...

Physics teachers may find the following for-sale tools to be useful supplements to our Lesson Plan and Pacing Guide section:

 

1. Task Tracker Subscription (annual purchase)
   A subscription allows teachers to set up classes, add students, customize online assignments, view student progress/scores, and export student scores. Task Tracker accounts allow your students to begin assignments in class or at school and to finish them at home. View our Seat and Cost Calculator for pricing details.
    
2. The Solutions Guide
   We publish a free curriculum with >200 ready-to-use Think Sheets for developing physics concepts. The Solutions Guide is a download containing the source documents, PDFs of source documents, and answers/solutions in MS Word and PDF format. An expanded license agreement is included with the purchase. (Cost: $25 download)
    
3. Teacher Presentation Pack
   This is a large collection of downloadable content packed with nearly 190 Microsoft PowerPoint slide decks, the corresponding Lesson Notes (as PDF and fully-modifiable MS Word format), about 170 animations (in .gif, .png, and .mp4 file formats), a countless number of ready-to-use images (including the original source documents that would allow for easy modification of those images), and a license that allows teachers to modify and use all the content with their classes on password-protected sites (such as course management systems).  (Cost: $40 download)
    
4. Question Bank
   We distribute a Question Bank that includes more than 9300 questions neatly organized according to topic. The Question Bank is the perfect tool for busy teachers or new teachers. Even if you don't use the website with your classes, the Question Bank will assist you in quickly putting together quizzes, tests and other documents with high-quality questions that target student's conceptions of physics principles. And if you do use The Physics Classroom website, the Question Bank is the perfect complement to the materials found at the website. (Cost: $25 download)