Lesson Plan

Acoustics 2: Echolocation in Action

Killer Whales depend on sound to find their food

Killer whales use sound to find their prey

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Grade Level:
Fifth Grade-Eighth Grade
Subject:
Aquatic Studies, Biology: Animals, Marine Biology, Oceanography, Oceans, Science and Technology, Wildlife Biology
Duration:
1 Class Period (50 min)
Group Size:
Up to 36
Setting:
classroom
National/State Standards:
NS.5-8.1 Science as Inquiry
NS.5-8.3 Life Science
NS.5-7.7 History and Nature of Science
Keywords:
orca, Humpback whale, marine biology, ecolocation, marine mammals, acoustics, underwater

Overview

Students will engage in a listening game that simulates how killer whales use echolocation to find food in Glacier Bay. They will try to determine the location of nine sounds made from various locations around a circle – in front, behind, or to the side of them. The data collectors will record the results and the class will analyze the data.  In the final round, students will be introduced to ambient noise to see how it affects the ability of the killer whales to locate their prey.

Objective(s)

Focus Questions:

  1. How do marine mammals use sound?
  2. What are the most common human-made sounds heard in the ocean?
  3. How might vessel noise affect the behavior (feeding, diving, respiration, resting) of marine mammals?
  4. Why is studying underwater acoustics important to the survival of marine mammals? 

Background

Our "Underwater Acoustics" curricula unit is divided into three lesson plans, each taking one class session to complete. They are part of our "Middle School Scientists" series that explore the fascinating research and resources of Glacier Bay National Park.

Check out the other lessons:

Acoustics 1: The World of Underwater Sound
Acoustics 2: Echolocation in Action
Acoustics 3: On the Trail of a Whale


Marine animals rely on sound to acoustically sense their surroundings, communicate, locate food, and protect themselves underwater. Some predators, like orcas (killer whales) and dolphins, use echolocation to find prey. By emitting short pulses of sounds called clicks, these marine mammals listen for echoes to detect prey and navigate around obstacles. Similarly, some fish are able to hear the killer whale clicks and avoid capture! Because these animals live in a relatively dark environment, being able to "see" acoustically is important to their survival. Engineers have mimicked this natural echolocation in SONAR (SOund Navigation And Ranging) which works the same way as echolocation in animals.

Some blind people use sonar by listening to the echoes from taps of their canes to help them avoid objects or help them determine how far they are away from a wall. Sound travels faster and farther underwater than through air. This means that sounds produced by marine animals and humans can travel great distances without much loss to the quality of the sound. These sounds are often reflected by underwater topography making it tricky to communicate using sound underwater. Marine mammals must be able to sort out all the echoes in the water in order to effectively communicate and feed. Whales and dolphin anatomy and sensory systems are adapted to meet this challenge. 

While humpback whales do not echolocate, they do use sound to communicate and may use sound to navigate and find food. Glacier Bay is currently studying the effects underwater sound may have on the feeding behavior of endangered humpback whales. Research shows that whales may move away from preferred feeding areas when disturbed by boat noise. Repeated disturbances could be detrimental to Alaskan humpbacks, who must feed enough during the summer to sustain themselves through their 3,000 mile roundtrip migration to and from Hawaii. Additionally, increased ambient noise, or background noise, may make it difficult for humpback whales and other animals to communicate, find mates and more.   

Materials

Procedure

Assessment

Underwater Acoustics Assessment

The following pre and post-tests provide assessment for material covered by the
entire Underwater Acoustics Curriculum series (Lessons 1-3)

Extensions

Extension

Have students compile their data and make comparisons. Create one large chart or bar graph using computer programs like Excel or Word Charts/Graphs. For a more challenging activity, have students plot actual location of snap versus real location and then find the percent of correct responses. 

Have students watch the short four-minute video, Dean Hudson, acoustic navigator. Dean is visually impaired and uses sound clues to navigate the city. Have several students wear blindfolds or close their eyes while making sound. They can either clap or snap their fingers. See if they can interpret the echoes to navigate around the room without bumping into objects or a wall. Be sure to give them plenty of space and use some students as monitors to help prevent trips or falls.
Here is the link to Dean Hudson's video: http://www.exploratorium.edu/listen/lg_dean.php  

Additional Resources

References/Resources

http://www.nps.gov/glba/naturescience/acoustics.htm
Glacier Bay National Park acoustics monitoring research 

http://www.nps.gov/glba/forteachers/middle-school-scientists-underwater-acoustics-video.htm
Enjoy this fun video produced by park researchers and local students.

http://www.teachengineering.org 
University of Colorado, Teach Engineering - Resources for K-12.   

The Cornell Lab of Ornithology, Effects of Human-Made Sound on the Behavior of Whales
http://www.birds.cornell.edu/brp/research/effects-of-human-made-sound-on-the-behavior-of-whales 

Bamfield Marine Sciences Centre Public Education Program
Oceanlink, An Ocean of Sound - An Exploration of Underwater Acoustics
http://oceanlink.info/oinfo/acoustics/acoustics.html 

Exploratorium, The Listen Project.
http://www.exploratorium.edu/listen/index.php

Vocabulary

echolocation, sonar, sound source