Lesson Plan

Acoustics 3: On The Trail of a Whale

Humpback Whale in Glacier Bay

Scientists can track whale migrations using sound.

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Grade Level:
Fifth Grade-Eighth Grade
Subject:
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.5-8.5 Science and Technology
NS.5-8.7 History and Nature of Science
Keywords:
marine mammals, Humpback whale, underwater, acoustics, vocalization, sound, tracking, migration, Glacier Bay National Park, whales, ocean, research, science

Overview

Students will learn that humpback whales make different vocalizations. They will
discover how scientists can use technology to track whales by listening to their vocalizations. Students will engage in a role play activity that simulates the tracking of whales using hydrophones as they migrate between Alaska and Hawaii.

Objective(s)

Focus Questions:

  1. How do scientists record and analyze underwater sounds?
  2. What can scientists learn about whales by listening to their sounds in the sea?
  3. How can this information help scientists in their efforts to protect whales and other marine animals? 

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


Studying whales can be challenging. Whales are often in remote oceans where there are few boats. Whales spend most of their life underwater out of sight of people. Scientists had to find a different way to track whales. Whales are very noisy and vocal animals. They sing songs, make audible blows, and communicate vocally during feeding and mating. Like people, whales also have different accents and voices. Some vocalize at a higher or lower pitch, or sing faster or slower. Whale calls even have regional differences: humpback whales in the Southern Hemisphere sing a little differently than humpback whales in the Northern Hemisphere. Scientists can track whales by the unique noises they make.

Each whale, like anything that makes noise, is a sound source. Hydrophones can record the noise of the whales underwater. Using hydrophones, scientists can determine where whales are, how many there are, where they are going, diving depth, and more. However, scientists need accurate sound receivers. For humans, our ears are sound receivers. They are what we use to hear. Not only can ears hear, but they can also determine direction. Since our ears are on two different sides of our head, they hear things at slightly different rates. If the sound source is on the right side of a person, the person's right ear will hear the noise slightly before the left ear. This is called the time of arrival difference and allows us to determine which direction a sound is coming from. Sometimes a sound source may be the same distance from each ear and it is hard to determine where the sound comes from. If we had three ears, it would be easier, but no one has three ears. However, we can have three (or more!) hydrophones recording the same whale. Underwater listening stations in the North Atlantic and North Pacific can do this. Using a process called triangulation, scientists use the time of arrival difference between several sound receivers (hydrophones) to determine where a whale vocalized.

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 compare their coordinates with actual humpback whale migration routes. Are they close? Discuss why these points are accurate/inaccurate to actual whale migrations. 

Additional Resources

Underwater Acoustic Monitoring Video

Sea Grant Alaska, Alaska Seas and Rivers Curriculum
http://seagrant.uaf.edu/marine-ed/curriculum/grade-6/investigation-4.html?task=view 

Glacier Bay National Park and Preserve, Acoustic Monitoring Program
http://www.nps.gov/glba/naturescience/acoustics.htm 

Humpback Whales in Glacier Bay
http://www.nps.gov/glba/naturescience/humpback-whales-in-glacier-bay.htm  

http://www.dosits.org/
This website will introduce you the science and uses of "Sound in the Sea." 

Vocabulary

frequency, sound receiver, sound source, time of arrival difference,  triangulation,