 |
|
|
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."
|
|
|
|
OBJECTIVE
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
PART
1 - GROUPING
MATERIALS
- perfume (or scented oils)
- sheet of paper
- pencil
PROCEDURE
- Work in groups of two. Use this drawing
 to
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.
- 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.
- Numbers each of the strips of paper, 1 through 5. These
numbers should be positioned at the top and middle of each
strip.
- 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.
- 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.
- 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!
- 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."
- 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.
- 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.
- Once the map is complete, compare the Tracker's map to
the "master" map. How did you do?
- Switch
roles.
 |
 |
| Two
Right Turns followed by a left |
|
Questions
- Why was it important to sniff the cards in numerical
order?
- Why were compass directions critical to constructing the
map of the migration?
- In order to create a more accurate map, what piece of
information was needed for each "leg" of the upstream
journey?
- How can this classroom experience be applied to the migration
of the salmon?
EXTENSIONS
ORIENTATION AND HISTORY
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).
WEB
CONNECTION
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
|
