Download Big Idea of the lesson: Ocean Currents

Title of Lesson: Ocean Currents
Grade level / science course: High School Earth Science
Big Idea of the lesson: Ocean Currents
Lesson Objective:
Given a globe, students will be able to draw and label the 5 main ocean gyres.
Students will be able to list the 5 main gyres of the oceans.
Students will be able to identify the effects on the oceans due to the coriolis effect.
Students will be able to list the reasons for increased and decreased salinities in the
oceans.
Students will be able to describe the effects of currents on climate.
Students will be able to list the positive effects of upwelling.
Student Objective:
You will label the 5 main ocean gyres on a globe.
You will take a quiz on ocean currents at the end of class.
Alignment with NC Standard Course of Study Competency Goal & Objective:
Competency Goal 4: The learner will build an understanding of the hydrosphere and its
interactions and influences on the lithosphere, the atmosphere, and environmental quality.
Objective 4.02: Analyze mechanisms for generating ocean currents and upwelling:
-Temperature
-Coriolis effect
-Climatic influence
Required Materials
(What and how much)
Distribution of materials
10 Black globes (1 black
globe will be distributed
by the teacher to groups
of 3 students)
20 (2 markers will be
distributed by a student
volunteer to groups of 3
students)
1 Clear pie plate with
water, pepper, and 1
straw (for teacher
demonstration)
Media (software, overhead
transparencies, video, etc)
Equipment (computer,
display, OHP, VCR, etc)
Word document with
input material (for
student notes)
Computer, Smart Board,
White board, overhead
projector
Safety (Precautions and reminders)
None, though students should be reminded that there should be no horseplay in the
classroom.
Time
10 min
Presentation Outline
Event
Opener
*NOTE: Students should be in assigned seats. Seats should be determined
based on behavior and ability. Each group of students should be made up
of different abilities.
Written on board:
Read page 545 in your textbook and write at least 3 bullet points of the
main ideas from the article.
Student volunteers should share their bullet points. Teacher should write their
responses on the white board.
Make sure the following is addressed regarding the article:
-Track surface currents using drifting items.
-Objects accidently become drift meters after falling off cargo ship.
-Objects lost include athletic shoes and bathtub toys (rubber duckies).
-Objects lost in North Pacific circulation.
-Objects washed up in Alaska 6 months later.
ASK: Have any of you heard of this before? Why should we care?
10 min
Give them the statistics:
70 million bottles of water are consumed in the U.S. each day.
In 2006, only 7% of plastic waste produced in the U.S. was recycled.
Americans threw more than 22 billion plastic bottles in the trash in 2006.
Have 2 student volunteers read the first 2 paragraphs of the following wikipage aloud. (Put wiki page up on the smart board).
http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patch
ASK: Who is in charge of cleaning up this mess?
Where did this mess come from?
Why should we care that it’s there?
Do you know think there might be more garbage patches like this out
there?
What can we do to help?
10 min
Input
Word document *Make sure students are taking notes and explain to them that
there will be a quiz at the end of the class period.
Ocean currents- masses of ocean water that flow from one place to another.
Why are they important?
Currents help to recycle nutrients within the ocean.
Currents and waves impact land and weather patterns.
What produces ocean currents?
Wind
Density differences
2 Kinds of Circulation:
Surface
Deep-Ocean
Surface Circulation:
Surface currents- movements of water that flow horizontally in the upper part
of the ocean’s surface. They develop from friction between the ocean and the
wind that blows across its surface
Gyres- huge circular-moving current systems that dominate the surfaces of the
oceans and whirl within an ocean basin.
5 main ocean gyres:
North Pacific
South Pacific
North Atlantic
South Atlantic
Indian Ocean
10 min
Modeling
Student Activity:
Pass out black globes to groups of students. Have a student volunteer pass out
markers.
Instruction:
Find the locations of the 5 main ocean gyres on your globes and draw dots on
those locations.
Draw the main gyres around the dots on your globes using arrows showing
direction.
10 min
After student groups have completed their gyres, the instructor should get the
attention of the class and model the correct answers for the location and
direction for the main gyres.
Input
Coriolis effect- the deflection of currents away from their original course as a
result of Earth’s rotation. Because of Earth’s rotation, currents are deflected to
the right in the Northern Hemisphere and to the left in the Southern
Hemisphere.
Each main gyre generally consists of 4 main currents.
Ie- Norther Pacific Gyre consists of North Equatorial Current, Kuroshio
Current, North Pacific Current, and the California Current.
It takes a floating object (like the rubber duckie) about 6 years to complete a
loop.
Current impact on climate: (Ocean accounts for ¼ of Earth’s heat transport,
wind transports the rest)
-When currents from low-lattitude regions move into higher latitudes, they
transfer heat from warmer to cooler areas on Earth.
Example- Gulf stream.
Anyone been deep-sea fishing? How far off our coast do you go? ~50 miles off
Oregon Inlet.
This impact on climate causes the U.K. and a lot of North-West Europe to have
warmer winters than NYC.
- As cold water currents travel toward the equator, they help moderate the
warm temperatures of adjacent land areas.
Example- Peru and western Africa.
Upwelling- the rising of cold water from deeper layers to replace warmer
surface water. (it’s wind induced)
One type is called coastal upwelling- winds blow toward the equator and
parallel to the coast- coastal winds + coriolis effect cause surface water to
move away from the shore. As the surface layer moves away from the coast,
it’s replaced by water that upwells from below the surface.
Upwelling brings greater concentrations of dissolved nutrients, such as nitrates
and phosphates, to the ocean surface. (supports marine productivity).
5 min
Modeling
Teacher Demonstration:
Put clear pie plate filled with water on the overhead. Sprinkle pepper on the top
of the water. Use the straw to blow over the middle of the pie plate. Have
students observe that the water is rippled by the artificial wind and that the
currents on the surface circulate around the edges of the pan. Point out that the
wind created is analogous to the coriolis effect.
Have students write down their observations in their notes and also draw a
picture of the demonstration.
10 min
Input
Deep-Ocean circulation
Density currents- vertical currents of ocean water that result from density
difference among water masses. (Denser water sinks and slowly spreads out
beneath the surface)
An increase in sea-water density can be caused by a decrease in temperature or
an increase in salinity.
What increases salinity?
Evaporation
Formation of sea ice
What decreases salinity?
Melting of sea ice
Precipitation
Runoff from land
High Latitudes- at the poles the surface water temperature decreases, then
sinks due to its density, it then moves along the seafloor in slow currents.
El Nino- At irregular intervals of three to seven years, these warm
countercurrents become unusually strong and replace normally cold offshore
waters with warm equatorial waters.
Onset is marked by abnormal weather patterns that drastically affect
economies (fish starve!) Too much rain.
La Nina- When surface temperatures in the eastern Pacific are colder than
average, a La Nina event is triggered that has a distinctive set of weather
patterns. Colder air is blown over the Pacific NW and Great Plains while
warmer much of the rest of the U.S. NC gets less rain.
We are currently in the middle of an El Nino oscillation
10 min
Check for Understanding
The following discussion questions should be asked and discussed in small
groups. After the class discusses in their small groups, the discussion
should be extended to the entire class.
Discussion Questions
1. During the 1700s, mail ships sailed back and forth between England
and America. It was noted that it took the ships two weeks longer to go
from England to America than to travel the same route from America to
England.
2. How could sailors avoid the Gulf Stream when sailing to America?
3. You are in a sailing upwind in a regatta in Banks Channel off of
Wrightsville Beach, NC. To the West of the sound you have a shallow
bank that is only about 4 feet deep. On the east side of the sound you
have a deep channel that is greater than 14 feet deep. The wind is equal
throughout the channel and the incoming high tide is moving in a
northerly direction up the sound. Where in the channel do you want to
be sailing?
4. You are swimming on the beaches of Bald Head Island, NC. A
hurricane is off the coast. When swimming, the local rip currents start
to take you out to sea. What should you do?
15 min
Closure
The following quiz questions should be displayed in the word document on the
smart board:
Quiz:
(Please answer on your own piece of paper and turn in)
1. Why do gyres in the Northern Hemisphere flow in the opposite direction of
gyres in the Southern Hemisphere?
Coriolis Effect
2. What increases salinity of the oceans?
Freezing
evaporation
3. What decreases salinity of the oceans?
Precipitation
Melting
Runoff
4. What are the 5 main ocean gyres?
N P, S P, N A, S A, I
5. Why are winters in the U.K. warmer than those in New York City even
though the U.K. is a higher latitude than New York?
Gulf Stream
6. How does upwelling affect marine organisms?
Brings in greater concentrations of dissolved nutrients to the surface.
Assign Independent Practice (Homework):
Create a KIMP chart for 5 terms we discussed today in class.
K- Term to know
I- Information about the term
M- Memory clue
P- Picture
Assessments
Pre assessment: Based on the student answers to the discussion questions in the opener,
the instructor will be able to get a feeling for what the students know about currents.
Formative Assessments:
The modeled gyre patterns on the black globes.
Answers to student discussions.
Student answers on the KIMP chart.
Closure quiz.
Reflection:
Overall, I like the layout of this lesson. It’s easy to read and flows well. The use
of the word document and smart board makes it so I wouldn’t have to be focused on the
board the entire time, but could instead put up the word document and focus on
explaining things and walking around the classroom.
My concern with this lesson is the amount of notes that the students would need
to take. Though I would assign that chapter’s reading the night before, I doubt students
would actually take notes and retain a lot of the information. I tried to cut the notes down
a little bit, but it still seems like a decent amount for a student to write down. However, I
do think it’s very important for them to write it down to have to refer to later on when
they’re studying. Also, by writing information down, they’re reinforcing that information.
Even though this lesson uses direct instruction, I think the amount of input and the
activities involved help to relay the information nicely. I don’t do any more than 10
minutes of input at a time and I involve activities and student-interest discussions as to
keep their interest during class. The lesson also contains a lot of formative assessments
that will allow me to figure out if my lesson is effective. I also really like my independent
practice for this lesson. Its focus on literacy would be beneficial to students as a study
tool. I think this lesson plan would be a thoughtful and effective lesson and I believe it
would be simple to implement in the classroom.