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Show Title

Teaching Guide
Guide Title
Growing Prairie
Indentifying Species
Follow Your Nose

Each winter, hundreds of thousands of white storks embark on a remarkable journey across Europe to the warmer climates of Africa. As you saw in "Flight Into the Unknown", scientists in Germany tag and track certain birds to try to learn more about their 8,000-mile flight. It is believed that storks use a complex system of sight, smell and even a means of detecting the Earth's magnetic field in order to navigate their way across the continents.

Migration is vital to the life cycle of many animals. Another creature that travels enormous distances during its lifetime is the salmon. Born in a shallow riverbed, young salmon later swim downstream to the open ocean, where they mature. As adults, they return to the same river in which they were born, where they produce new young and eventually die.

Research shows that salmon most likely use their sense of smell during this migration. By detecting minute differences in chemical concentrations within the water, they can to navigate river junctions to eventually return to the site where they spent their first few years of life. In this activity, you'll use your sense of smell to follow a scented path. As you detect each odor placement, you'll use this information to help construct a map of the "river" as you head "upstream."

note to educators


This activity page will offer:

  • an opportunity to use the sense of smell as an observational tool
  • a review of degree headings and compass directions
  • an experience in collecting and analyzing data
  • an experience in using data to create maps



  • perfume (or scented oils)
  • sheet of paper
  • pencil


  1. Work in groups of two. Use this drawing image of compassto familiarize yourself with compass headings and how degrees are used to indicate direction. Once both team members understand degree headings, move onto the next step.
  2. Prepare a sequence of "sniff" strips that will be analyzed your teammate. To produce these cards, you'll need five strips cut from a sheet of paper.
  3. Numbers each of the strips of paper, 1 through 5. These numbers should be positioned at the top and middle of each strip.
  4. To either side of the number, place two compass headings. These headings indicate the direction of each fork of the river. The left side should have a value between 270 and 0 (360) degrees. The right side should have a value anywhere between 0 and 90 degrees. Remember to work separately from your partner - you'll be testing them with these scent strips later on.
  5. Places a drop of scent on either the right or left side of each of the strips. If possible, use a different scent on each strip.
  6. As the scents and headings are added to the scent strips, record the route in a "master" map that illustrates the direction indicated by your clues (SEE EXAMPLE). But don't show this map to your partner!
    image of scent strip
  7. As soon as all five strips are scented and your master map is complete, decide which one of you will be the first "Scent Tracker."
  8. The Tracker begins at the "mouth" of the river. Examining the strips in numerical order, the Tracker sniffs each one to determine the route (right turn or left turn) identified by each scent.
  9. As each strip is sniffed, the Tracker uses a pen and paper to record the route up the river, remembering to pay close attention to the direction of each turn and to each the compass heading.
  10. Once the map is complete, compare the Tracker's map to the "master" map. How did you do?
  11. Switch roles.
Image of map
Two Right Turns followed by a left  



  1. Why was it important to sniff the cards in numerical order?
  2. Why were compass directions critical to constructing the map of the migration?
  3. In order to create a more accurate map, what piece of information was needed for each "leg" of the upstream journey?
  4. How can this classroom experience be applied to the migration of the salmon?



Although the ancient Egyptians did not have compasses, they were able to align pyramids in precise north/south/east/west orientations. How could this be accomplished without exploiting the magnetic field of the Earth? (using the directional cues found in shadows).


Salmon Article from Seattle Times
This article from Seattle Times presents a rich overview of what we know (and don't know) about salmon migration

Atlantic Salmon Links
A collection of links to Atlantic salmon fishing, aquaculture and legislation

Atlantic Salmon Unlimited
An essay describing the biology of the Maine Atlantic salmon



The activities in this guide were contributed by Michael DiSpezio, a Massachusetts-based science writer and author of "Critical Thinking Puzzles" and "Awesome Experiments in Light & Sound" (Sterling Publishing Co., NY).

Academic Advisors for this Guide:
Corrine Lowen, Science Department, Wayland Public Schools, Wayland, MA
Suzanne Panico, Science Department, Fenway High School, Boston, MA
Anne E. Jones, Science Department, Wayland Middle School, Wayland, MA

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