6/16/14 9:16 AM
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An Introduction to Sound through Frog Calls
Part of:
Inquiry Science with Dartmouth
Katie Duryea, Biology Department
Overview
This module is meant to introduce students to the basic properties of sound (wavelength, frequency, and
amplitude). Additionally, it introduces students to local (to VT/NH) frog species and sets the stage for
students to monitor frog calls.
Science Standards
PS4.A: Wave Properties
A simple wave has a repeating pattern with a specific wavelength, frequency, and amplitude. (MS-P4-1)
A sound wave needs a medium through which it is transmitted. (MS-PS4-2)
Focus Questions
How does sound work? Students will focus on understanding the properties of sound and how they can be
measured. Through introducing the basic features of a sound wave (i.e., wavelength, frequency, and
amplitude), students will learn how to compare different sounds and develop testable hypotheses
regarding how sounds may differ.
Objectives
Through this lesson, students will:
•
Learn how to identify wavelength, frequency, and amplitude of a sound wave.
•
Learn the different ways to graph sound.
•
Identify sounds that differ in their wave properties (e.g., high frequency vs. low frequency).
Background
Review basic properties of sound (this is covered on the first page of the worksheet):
An Introduction to Sound
Sound can be thought of as a wave! When scientists measure sound, they use terms that describe
the wave.
Wavelength: the distance between two high or low points on a wave.
Amplitude: how loud or soft sound is.
Frequency: the number of sound waves in a certain amount of time.
In addition to using the worksheet developed here, we found it helpful to develop a probe for your current
science textbook. For example, after introducing sound properties, have students find the terms
(wavelength, amplitude, frequency) in their textbooks and describe the context in which they’re used.
This is often done through comparing different musical instruments. An example warm-up question could
be: “How would you expect the frequency of sound to be different between a bass guitar and a ukulele?”
A: The bass guitar would have a lower frequency (also called “pitch”).
Materials
Worksheet, computer, speakers. Smartboard technology is helpful for labeling features of the sound wave,
but this could also be done on a white board.
Preparation
Frog calls are displayed using Raven Viewer software. This software displays the sound wave as it is
being played, allowing students to directly connect wave properties to what they are hearing. The
software is free to download and works on most browsers for both PC and Mac.
1) Download and familiarize with Raven Viewer
Before the lesson, download the software here: http://macaulaylibrary.org/raven-viewer
Follow the instructions provided on the website (copied below):
Download
Raven Viewer uses QuickTime and a custom plugin.
1. Install the Firefox web browser (suggested, but not required)
2. Install the Apple QuickTime (done, if you have itunes)
3. Install Raven Viewer for Windows or Mac OSX
4. Restart your computer
Flash Alternative
If you prefer not to install QuickTime, we also support a Flash based audio/video player.
1. Install the flash plugin (probably already installed)
2) Locating frog calls in the Macauly Library
This lesson is designed to introduce three frog species that are native to the NH/VT region. The first call
(Frog 1 on worksheet) is from the bullfrog. You can locate the call here:
http://macaulaylibrary.org/audio/168994
Click on the Raven Viewer icon (red sound wave on top right of webpage, below the “Share>>” link) to
load the Raven Viewer file for each call. It is helpful to have each call loaded in a browser window before
the lesson begins. The two other calls are the gray treefrog (Frog 2) found here:
http://macaulaylibrary.org/audio/88762 and the spring peeper (Frog 3) found here:
http://macaulaylibrary.org/audio/176101
Procedure
This lesson can be taught in one or two class periods. First, introduce students to the basic properties of
sound. We followed this procedure:
1) Start with a warm-up question about sound. We used “How could you draw a sound?”. This introduced
them to thinking of sound as something you could visualize and measure.
2) Introduce wavelength, amplitude, and frequency. To do this, we displayed page 1 of the worksheet on
the Smartboard and labeled each part of the sound wave on the worksheet diagram. We then had students
work in groups to complete the “Draw” section of the worksheet and did a pair/share of their responses. If
splitting this activity into two lessons, you could then do a probe of sound using a science textbook or
science article. We had the students locate key terms in their textbooks and describe their meaning to their
desk partner.
3) Play sound calls from the Macauly website. We played each call twice. Once just for the students to
listen and the second time for them to focus on the worksheet questions. After each call was played, we
had the students work individually on the final “Questions” section of the worksheet and then did a
pair/share of their responses. Finally, we had each pair share their responses with the class and discussed
their findings.
4) Bonus! If time permits, we found that students often wanted to look up other calls on the website. If the
rest of the activity goes well, you can reward them with a bonus sound call of their choosing. Our students
wanted to hear a wolf pack and blue whales. This can be a good opportunity to connect to other animals
that they’ve learned about and encourage creativity (“How do you think the sound of a blue whale will
compare to that of a frog?”). To find bonus calls, go to http://macaulaylibrary.org/ and type your desired
animal in the “Search recordings by species” box (labeled in yellow on the top right of the page). You can
search by common names.
Assessment
Teachers can assess the student based on their answers to the worksheet and their responses
during group sharing sessions.
Extensions
Future lessons could explore the calls of other animals available on the Macaulay Library website. For
example, whale calls could be used to introduce how sound travels through water vs. air (NGS Standard
MS-PS4-2: A sound wave needs a medium through which it is transmitted.).