Activity
Part One - Wind
1. In yesterday’s lesson the students mapped “Message
in a Bottle” to describe ocean currents. They will
use that information in today’s lesson. Remind students
that yesterday they used bottles floating on the ocean
to discover ocean currents. Reveal the ocean current map
to students.
2. Have students compare their maps they created yesterday
on the overhead. What is similar? What is different?
3. Ask students to look carefully at the surface currents
map. Draw their attention to the oceans. Is there a boundary
where one ocean starts and another stops?
4. Ask students, “Since the world really has one
large ocean, what might cause the water to move in the
fashion it does with some surface currents flowing to the
equator and others away from the equator?”
5. Explain to the students that they are going to explore
some of the different factors that affect ocean currents.
Divide the class into groups and have the groups do the
following:
i.) In a baking dish place the sand to construct a beach
at one end.
ii.)Fill the baking dish with water to a depth of about
5 centimeters.
iii) Place the fan or hair dryer on one side of the container
so that the fan can blow onto the surface of the water.
It should be aimed down the tank along the surface of the
water at about a 45-degree angle. Switch on the fan (or
hair dryer). Allow 2 minutes for each trial. Let the students
observe the results.
6. Select a few students to share their results with the
class.
7. When students have finished sharing, ask them to repeat
the above experiment by changing one variable. Examples
might be force of the wind, angle, water depth, water temp,
etc. Again they should collect data and share their results
with the class before the end of the period.
8. At the end of class ask students to describe how wind
affects surface ocean currents.
Part Two - Temperature
1. Ask students to think about the primary source of energy
for our planet, the sun. Where are the sun’s rays
most concentrated? [equator] How does that concentration
of solar radiation affect the oceans? [heats them] Where
do they think the oceans are coldest? [polar regions] What
evidence supports this belief? [presence of icebergs and
glaciers]
2. Divide the class into groups and send them to their
laboratory stations.
3. Groups should complete the following while at their
laboratory stations:
i) Fill a clear baking dish with warm/hot water colored
red to represent the warm water near the equator.
ii) Place one or two blue ice cubes at each end of the
baking dish, representing the cold water near the poles.
iii) Invite them to predict what will happen as the ice
cubes melt.
iv) Students will observe the results. (The cold water
will sink and move along the bottom of the baking dish
toward
the warmer water in the middle. The warmer water will move
toward the ends of the baking dish; as the cold water begins
to warm, it will begin to rise.)
v) Have students use a
straw to simulate wind currents. How does this affect the
flow of the hot and cold water?
vi) Students should record the results of their experiments,
accompanying their reports with labeled diagrams and an
explanation of how differences in water temperature in
different parts of the “World Ocean” cause
ocean currents.
4. When the groups have finished, invite them to share
the results. What did they observe? How do hot and cold
water move to create currents? How does wind play a role
in those currents? How does temperature affect the density
of the water? [Colder water is denser so it sinks; warmer
water is less dense so it floats.]
Part Three – Salinity
1. Ask students, “When you think about oceans and
lakes, what quality of ocean water makes it so distinguishable
from lake or river water? [salinity]
2. Tell students that different parts of the ocean are
saltier than others. Ocean regions near igneous formations
are less salty, while ocean regions near sedimentary formations
are saltier. How do you think the amount of salt affects
density? Do you think that will affect the way ocean currents
flow?
3. Divide students into groups and send them to their laboratory
stations.
4. Have groups create 5 different concentrations of salt
water using the directions below. Students should add 2
drops of food coloring to each solution so that the differentiating
salinity can be distinguished later on.
5. Have students put 100 mL of water in each beaker. In
beaker one they should place 2 drops of red coloring and
5 grams of salt. Beaker two should be colored yellow with
40 grams of salt in it. Beaker three should be colored
green and contain 80 grams of salt. Beaker four should
be colored blue and contain 140 grams of salt. Beaker five
should be colored purple (one red drop and one blue drop)
and contain 220 grams of salt.
6. Have groups tilt their 6th beaker and slowly and carefully
pour the solutions into the beaker. They should pour the
purple solution, then the blue, then the green, then the
yellow, and finally the red. Students should carefully
record their results.
7. What do they notice? What happens to the layers? Do
they mix?
8. As a class, determine how salinity might affect ocean
currents.
Closure
How else might we work to determine the way the
oceans move and why? What characteristics of ocean
water might affect its currents?
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Embedded
Assessment
As
the students discuss their explorations are they able
to explain that winds tend to move the surface currents
in the same direction they are flowing? Do they explain
how salinity and temperature affect deep ocean currents?
Can they explain how temperature and salinity affect
density?
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