Lesson Plan #3
Jane Zegers
3/25/14
Grade level: 11th/12th
Subject Area: Earth Science
School: Martin Luther King High School
Physical Setting: Classroom
District: DPS
Lesson Plan Title: The Coriolis Effect
Outcomes:
At the end of this lesson students will:
1. Model the rotation of the Earth and demonstrate the Coriolis Effect.
2. Explain how the Coriolis Effect influences global winds and ocean currents.
Standards: HSCE
E4.2A Describe the major causes for the ocean’s surface and deep water currents, including the
prevailing winds, the Coriolis effect, unequal heating of the earth, changes in water temperature
and salinity in high latitudes, and basin shape.
E4.2f Explain how the Coriolis effect controls oceanic circulation.
Rationale:
In the previous lesson, students were given a brief introduction to the Coriolis effect. The Coriolis
effect plays a major role in the movement of surface ocean currents, however it is often difficult
for students to visualize how it works. This activity will allow students to physically model the
Coriolis effect so they can directly see how it influences winds and currents. The lesson also helps
students realize the interconnection between the land, atmosphere, and oceans.
Materials:
 Copies of the Coriolis Effect Activity (procedures and questions)
 Balloons
 Markers
Procedures/Development of the Lesson:
Introduction:
The Do Now assignment is to prepare the Know/Observed/Learned chart (see activity sheet) and
fill in the first column. Explain to the students that they are to write whatever they know about the
Coriolis effect. If they do not feel they know anything about the Coriolis effect, they should write
what they think it means or what they would guess it is or what it does. Leaving the column blank
or writing “I don’t know” is not an option. Emphasize that there are not right or wrong answers for
this part of the assignment. The purpose it gauge individual learning.
Tell the students that today they will model the Coriolis effect. Have the students read through the
first several steps of the procedures and demonstrate how to setup and move the balloon. Ask the
following:
 What does the balloon represent? (The Earth)
 What is the equator and where should I draw it? (A line around the center or middle of the
Earth)
 We know that the Earth is a sphere and the equator divides it into two halves. What is the
top and bottom half called? (Northern and Southern Hemisphere)
 Where are the North Pole and South Pole located? (The North Pole is at the top of the globe
and the South Pole is at the bottom)
 How does the Earth move in space? This question should spark a discussion. Be sure to
review how the Earth travels around the sun, how it spins, and why the sun rises in the east
and sets in the west.
Explain that students will work with a partner on this activity and show them how the person
holding the balloon should rotate the balloon from left to right. Continue to spin the balloon and
have the students observe how it moves counterclockwise when looking down at the North Pole
and clockwise while looking at the South Pole. Remind the students to make sure they are turning
the balloon correctly when they work in partners.
Methods and Procedures:
Students are working with a partner for the modeling portion of the activity. I will be circulating
through the classroom assisting pairs with procedures and clarifying concepts. The bulk of teacher
led instruction occurs in the introduction and demonstration of the activity. The actual activity is
student driven exploration with the teacher offering support or guidance when needed. Students
should work independently on their Know/Observed/Learned chart but may consult their partner
in answering the other questions.
Issues to address with pairs or in small groups:
 Make sure students rotate the balloon from left to right during the entire activity.
 Instruct the student that is drawing the line to try to draw it straight from the pole to the
equator and not move with the balloon.
 The student spinning the balloon should move it fast enough to result in a significant curve
of the line. This may take a few trials.
 When students are trying to determine in which direction the line is deflected, have them
look down the path from the pole. Making arrows along the line will be helpful. Suggest that
they draw a dotted line along the intended path from the pole to the equator and observe
which direction, right or left, the curved line moves from the dotted line.
 Suggest that when answering question #6, students should turn their books and look down
the path of the currents to determine if they behave in the same manner as the line they
drew on the balloon.
Closure:
Survey: Ask the students how many teams…
 Discovered that the line would curve (all should raise their hands)
 Found that the line curved to the left in the Northern Hemisphere
 Found that the line curved to the right in the Northern Hemisphere
 Think that curving to the right is the correct answer (this is correct)
 Discovered that the lines in the Northern and Southern Hemisphere curved in opposite
directions
Ask the students what they think the error was for groups that observed the line deflecting to the
left in the Northern Hemisphere (the balloon was being rotated from right to left – opposite from
what it should be).
Accommodations/Adaptations:
Special education students may be paired with a regular student or added as a third member.
Students that have difficulty describing their observations may draw pictures.
Assessment/Evaluation:
Ongoing observation of students during the activity will show if they are getting the expected
results and are able to understand how the Coriolis effect works through physical manipulation of
the model. Students should be able to verbalize their observations and explain why the lines are
deflected. The Know/Observed/Learned charts show the progression of learning and how well
students understand the main concepts at the end of the activity. Answers to question #4 and #5
will determine if students have made the connection between Earth processes, global winds, and
surface ocean currents.
Reflection:
This activity was a great way to model a difficult concept. The students were engaged the entire
time and were able correctly demonstrate the Coriolis effect. The Know/Observed/Learned chart
was a good way for students to track their own learning. The most difficult part of the activity for
the students was to determine which way the line was deflected and to see the same pattern in the
ocean currents. In the future I will add several different examples for students to practice this skill.
Overall, I believe the objectives of the lesson were met.
Coriolis Effect Activity
Prepare the following chart
Know / Think
Observed
Learned
 In the first column, write what you know about the Coriolis Effect or what you think it means.
Procedure
1. Blow up a balloon.
2. With a marker, draw the equator on the balloon and label the North and South Poles.
3. Hold the balloon at eye level and rotate it left to right, simulating the rotation of the earth. The North
Pole should stay facing up during the entire activity.
4. While 1 partner rotates the earth balloon, the other examines the movement of the earth from the
North Pole perspective and from the South Pole perspective. You should observe that the North
Pole turns counterclockwise and the South Pole turns clockwise. If not, you are rotating incorrectly.
5. While 1 partner continues to rotate the balloon steadily from left to right, the other slowly tries to
draw a line straight south from the North Pole to the equator.
6. While the earth continues to rotate, 1 partner tries to draw a line straight north from the South Pole
to the equator. What you see happening to your line is the Coriolis Effect.
Questions – complete all questions in complete sentences on the back of your chart.
1. How did the line from the North Pole to the equator curve? (Right or left from the intended path)
2. How did the line from the South Pole to the equator curve? (Right or left from the intended path)
3. Write on your chart what you have observed about how the Coriolis Effect works.
4. Predict how the lines in the Northern and Southern Hemispheres would curve if the Earth were
rotating in the opposite direction.
5. Look at section 24.1 in the book. What is the primary cause of surface currents in Earth’s oceans?
6. On page 533, do the winds and currents in the image match what you have observed about the
Coriolis Effect in the Northern and Southern Hemispheres? Explain.
7. Write on your chart what you have learned about how the Coriolis Effect works.