Masking Marine Mammals:
An Introduction to Noise Pollution
Heather Heenehan
Duke University Marine Laboratory
135 Duke Marine Lab Road, Beaufort, NC 28516
Website: http://sites.duke.edu/heatherheenehan/for-teachers-and-students/
Email: hlh18@duke.edu, Twitter: @spinnerheather
Introduction: When you think of pollution in the ocean what comes to mind? Plastic bags? Balloons?
What about noise? Can noise be a “pollutant” in the ocean too? This lesson plan will introduce
students to the concept of noise and noise pollution and will illustrate some of the possible effects of
increasing noise in the ocean. Students will first think about sound in their own environments and
how they use sound and then move towards thinking about sound in the ocean, how efficiently sound
works in the ocean and the possible effects of an ocean that is getting louder and louder every year
on the marine mammals that live there.
Learning Objectives:
1) Explain the importance of sound for
marine mammals.
2) Describe what “masking” means.
3) Discuss noise pollution as it relates to
marine mammals.
Appropriate Grade Levels: Middle
School, Grades 6-8
Approximate time: 45 minutes with
optional final product homework
assignment
Group Size: 25-30 students, utilize small
groups of 4 students, the groups should
have an even number of students
Setting: Ideally students would start
inside and then move outside
Resources needed for students:
Clipboards or something to write on if
students go outside
Worksheet per group or per student
Pen or pencil
Resources needed for educators:
This lesson is a modified version of one
from the NOAA Outreach and Education on
Protected Species.
-The website for that NOAA OEPS lesson
provides great background for the lesson:
http://www.nefsc.noaa.gov/psb/NOEPS/doc
uments/B_Lesson_3-5_NOEPS.pdf
-Noisemakers (spoons and pots, musical
instruments, etc.)
Lesson Activity
1. Break the students up into small (3-4 person) groups. These
groups will be used throughout the activity. These activities can be
done as a group or each student can be given a worksheet and the
instructor can call on individual students for a class brainstorm. Have
students pick a recorder and a spokesperson for their group if they are
working in small groups.
2. Begin by telling students you are going to play a little word
association game. I’m going to say two words and I want each of you to
tell the recorder the first thing that comes to mind so he or she can write
it down in your Question 1 box. The students will have 3 minutes.
Words: OCEAN POLLUTION
3. Call on the spokesperson from each group to tell us what your
group wrote down.
4. The instructor should write the ideas on the board grouping
them by themes.
5. If the students volunteered sound as an ocean pollutant tell the
students we will be focusing on that for the rest of our time together. If
students did not have noise on their list, tell them, I’m going to add one
more to our list.
6. Tell students we will be focusing on thinking about why we
consider noise or sound as a “pollutant” and the possible effects of this
pollution on marine mammals.
7. In the classroom the instructor should review the following
topics at this point: Sound
http://www.dosits.org/science/sound/whatissound/, How marine
animals use sound
http://www.dosits.org/animals/useofsound/animalsusesound/,
Specifically how marine mammals use sound: communication (moms
and calves, in pods or groups, with potential mates, etc.) navigation,
finding their prey. It would be useful at this point to talk about why
8.
9.
10.
11.
12.
13.
14.
15.
humans make sounds. What are we trying to do? Then to think about marine mammals.
The students should be able to answer the question how do marine mammals use sound and should realize the
importance of sound for marine mammals.
Tell the students we will be moving outside and that they should bring their worksheet and their clipboard but
they don’t need anything else. This activity can also be completed inside.
We’re going to play another game. The first part is silent. I want you to take 30 seconds, I will time it and I just
want you to listen.
Now that you have listened, hopefully you paid attention, in your groups I want you to write down in a numbered
list how many sounds you could hear.
We are marine mammal sound researchers so I want you to pretend you are in the ocean. So in our situation, the
bird sounds are our whale sounds. Did we hear any bird song? Were there any sounds that you think interfered
with our hearing bird song?
The instructor(s) should get out the noisemakers and make noise for 10 seconds. Ask the students, did you hear
bird song? If yes, was it harder to hear the bird song? If no, do you think if there was bird song you would have
heard it?
Explain to the students that when one sound “covers” another, it is called masking. See
http://www.dosits.org/animals/effectsofsound/marinemammals/masking/ for more information. This is one
possible effect of sound pollution in the ocean. Have students discuss again what types of sounds could be
masked. Are these important sounds for the animals?
We will illustrate masking another way. This masking activity can be done in many different ways and each can
be modified to suit the situation. Here are two options.
Option 1: Modified from http://www.nefsc.noaa.gov/psb/NOEPS/documents/B_Lesson_3-5_NOEPS.pdf
Have each pair of students face each other and start talking about what they ate for dinner last night. Pause the
activity. Easy. Now have the one pair stand directly behind each student in the other pair. I want both pairs to
repeat that conversation about dinner last night over the first pair. Think of how each additional pair talking
makes it more difficult to hear your partner. This is what marine mammals have to deal with when trying to
communicate with all the other animals and ocean noise activities surrounding them.
Pair 1: Student 1 and 2
Pair 2: Student 3 and 4
Situation 1: 1 and 2
3 and 4
Situation 2: 1 3 4 2
Option 2: Have students stand in a circle. Give each student a small slip of paper with the name of a fruit on it.
Ideally each student will have a pair but it is okay if they do not. The instructor should also have a word and give
the same word to another instructor. Tell the students that you want them to find their match but that they cannot
move. We will do this in rounds. Have the two instructors with the same word start. They find their match. Easy.
Now pick a few of the students on opposite sides of the circle. Do any of them find a match? Are we confident
that we made all the matches we could with those students? Now everyone go! Get everyone back together. Have
students put their hands up if they found a match. If you didn’t find a match, what was your word? Did any other
students have that word? Were we successful in making matches? How hard was it to find your match when
everyone else was making noise?
16. Discuss how marine mammals deal with this problem. Some of them talk higher or lower in frequency. Others
make louder sounds. Others just give up. We could also take turns and not all vocalize at once.
17. Okay one more game: If we were dolphins in the ocean. What types of sounds might we hear? In your group list
as many sounds as you can in 1 minute. Ask the students how many of them had sounds from other marine
animals? Did you have other whales? What about fish? Who had sounds from waves or wind? Who had sounds
from humans like boats or sonar?
18. Come back to the list of pollutants we came up with. Explain to the students that even though we focused on noise
pollution today, remember this list of pollutants. Each of these pollutants has the chance to affect marine
mammals. So we can’t think of the effects of only one. We need to remember that they’re facing multiple sources
of pollution every day.
Final Product
Worksheet completed.
Option: As a wrap up we would like students to write a blog explaining why they should or shouldn’t
be worried about noise pollution. Students should be told that they need to talk about masking and the
importance of sound for marine mammals and that they should research one example of where a
marine mammal sound could be masked by a human-made sound.
Assessment
Assessment can either be done with a short quiz or survey or through grading the student’s blog
entries. Students should be able to explain the importance of sound for marine mammals, to describe
what “masking” means NC
and Essential
to discuss Standards:
noise pollution
as it8.E.1
relates to marine mammals.
6.P.1,
Next Generation Science Standards: MS-PS4, MS-LS2-4
Notes: If I were to visit the class I would explain my research on Hawaiian spinner dolphins and how the dolphins live in
a place where lots of humans like to hang out. I would show students pictures of the bays and ask them to think of sounds
from humans I might record in my bays. I will play sounds for the students that I have recorded where marine mammal
and human sounds overlap and examples of human-made sounds.
Appendices: Worksheet, 2 sides, see next page
Masking Marine Mammals
Group Member Names __________________________________________________________________
Recorder_____________________________________________________________________________
Spokesperson _________________________________________________________________________
Word Association 1:
Brainstorm 1:
Brainstorm 2: