what causes ocean water near the equator to be warmer than ocean water farther north

Seasons and Why the Equator is Warmer than the Poles

Author: Ann Bykerk-Kauffman . Section Of Geological and Ecology Sciences, California State Academy, Chico

Summary

One of the most common and persistent scientific misconceptions is that Earth'due south seasons are caused by Earth'south distance from the sun. A closely related and perhaps more than common misconception is that the equator is warmer than the poles because the equator is significantly closer to the sunday than are the poles (i.eastward. the equator "bulges out" toward the sun). Fifty-fifty professional geoscientists sometimes hold the latter misconception. It is, for example, stated as fact in 1 of the (to remain nameless) "Geology Underfoot" series of guidebooks. Many people combine the 2 misconceptions. For example, many people know that the southern hemisphere experiences winter while the northern hemisphere experiences summer (and visa versa), but they explain this phenomenon by erroneously stating that the northern hemisphere is closer to the lord's day in June than information technology is in December because Earth'south tilt toward the sunday in June makes the northern hemisphere "bulge out" toward the lord's day.

The guided-discovery activity described here helps students confront and overcome both of these common misconceptions as it guides students toward an agreement of how and why the angle of incident sunlight determines the intensity of the solar energy that strikes the basis and hence how the angle of incident sunlight tin can be used to explain both seasonal and latitudinal differences in temperature. Along the style, this activity helps students visualize the truthful dimensions of the solar organization and the diverse objects within it. This seemingly unrelated topic is included in this activity because an accurate perception of the scale of the solar system helps students sympathise that (1) Earth'due south equator is not significantly closer to the sun than are its poles, and (2) all sunrays intercepted by Earth are substantially parallel to each other, whether they strike the equatorial or polar regions -- a concept that is essential for agreement how and why the bending of incident sunlight varies systematically with latitude and season.

Learning Goals

In this activity, students confront their misconceptions about seasonal and latitudinal temperature variations, come to understand the true causes of these phenomena, practice using simple physical models to solve problems, and develop their 3-D visualization skills.

The specific content learning objectives are:

• Visualize the truthful-calibration proportions of the solar system -- the sizes of objects and distances between them.
• Clearly and fully explicate why it is warmer at the equator than information technology is at the poles.
• Evidence how the tilt of Earth'due south axis and Globe's revolution around the lord's day crusade seasonal variations in temperature past causing seasonal variations in twenty-four hours length and maximum daily solar altitude.

Context for Employ

This activeness has been extensively tested, revised and retested for more than 15 years in the Concepts in Earth and Infinite Sciences course for future teachers at California State University, Chico. It should work well in Globe science and astronomy courses from centre school to college level. Because this activity is designed to guide students toward discovery of the concepts, it works best if complete it before reading any explanations of or receiving any directly instruction about the causes of the seasons or why it is warmer at the equator than it is at the poles.

Description and Teaching Materials

• Student Handout (Microsoft Word 522kB Sep5 09) for the Activity on the Seasons and Why it's Warmer at the Equator than the Poles
• Grid (Acrobat (PDF) 240kB Sep5 09) to exist printed on an overhead transparency.
• Other materials needed (in chronological order):
  • Per Table:
    • Flashlight
    • Collection of spherical objects to represent celestial bodies as follows:

      

    • Light fixture with a single unshaded frosted light bulb.
    • Pencil inserted into i 3 inch diameter white Polystyrene ball. An ordinary Styrofoam brawl volition not do; the ball must be opaque. Suggested source: Molecular Model Enterprises, 116 Swift St., P.O. Box 250, Edgerton, WI 53334, (608)884-9877. Prices are under $1 each.
  • Per classroom
    • Yellow or white exercise ball -- 65 cm (25.5 inch) to 75 cm (29.five inch) diameter, to represent the sun, which has a diameter of 1.4 one thousand thousand km. (The ideal scale model size would exist 70 cm or 27.v inches.)
    • Do brawl stand
    • 10 cm Pilates toning brawl to represent Proxima Centauri, the nearest star
    • Outdoor space at least 120 grand long
    • Tape measure out (optional; students tin can too measure distances by counting paces)
    • 3 ring stands
    • Overhead projector
    • Large piece of white potent (foam backed) poster board
    • Large globe on a stand up; 30" - 36" diameter is best.

Teaching Notes and Tips

General Comments: This activeness can exist completed in ii hours if students give it a superficial handling, but three to four hours are required for an in-depth exploration, including the confrontation of any misconceptions and the construction of a full understanding of the concepts.

Equally students work through these activities, encourage them to engage in lively conversations, continually brainstorming, questioning, and checking for consistency. In my feel, students are often inconsistent -- gently call them on this. For example, one student adamantly insisted -- despite the protestations of her squad members -- that the equator was not significantly closer to the sun than were the poles. Yet, she and then attributed the temperature differences betwixt the equator and the poles to differences in their distances to the sun. I pointed out that she was contradicting herself, which acquired her to engage in some deep thinking which culminated in an "Aha!" moment that she absolutely delighted in.

Notes on Lab Activity #1: Scale Model of the Solar System

• I recommend doing the outdoor activity equally a whole class with educatee volunteers to represent each planet; choose the tallest person in the grade to footstep off the distances. When you get to "Earth," have the students place the moon at the appropriate distance from Globe and point out that, coincidentally, the moon and sun await the same size as seen from Earth.
  
• In the table at the lesser of page 2, fill in appropriate landmarks in your local area that are located at the model distances.
  
• Questions one and 2 on folio 3 typically generate a dandy bargain of discussion. The students may demand a fair amount of prodding and questioning to get to the correct answers.
  

Notes on Lab Activity #2: Why is it Warmer at the Equator Than it is at the Poles?

• Place the globe on a counter and so that it is tilted to the correct or left (i.east. Spring or Fall position) with the Pacific Ocean facing the overhead projector -- having a relatively featureless part of the globe face the projector helps students see the grid projected on it more clearly, without being distracted by the details of circuitous shorelines or borders.
  

Notes on Lab Action on the Causes of the Seasons

• Before students brainstorm this activeness, explicate to them that each group will be asked to codify an initial hypothesis to explicate the causes of the seasons. The students will then attempt to use this hypothesis to explicate a series of facts. If their hypothesis is not up to the job, they must discard and reformulate, modify, or add to their initial hypothesis until it can provide a satisfactory explanation of the facts.
  

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At the cease of this activity, I typically assess student learning past having student groups present their answers to the remainder of the form. I separate the different parts of this activity amid the student groups, assigning each group to prepare illustrations and orally present their office to the balance of the course. Each presentation is then followed past a whole-form discussion.

I assign this Homework Assignment on the Causes of the Seasons (Microsoft Word 58kB Sep5 09) every bit assessment, but also as a fashion for students to consolidate the understandings that they have built during the guided-discovery action. Students oft benefit from a formal traditional presentation of concepts that they have previously struggled to grasp while working through a hands-on guided-discovery activity. When the traditional presentation follows guided discovery, information technology can be very meaningful, building students' conviction in their freshly hatched ideas and organizing their discoveries into a logical and elegant construct. Without some kind of traditional presentation of the concepts, students are often so unsure of themselves that they feel lost. Yet, in my classes, students rarely complete (allow alone embrace the material presented in) a "Read Chapter 3" type of assignment, even when it'southward followed by a quiz. Only the vast bulk of students volition complete an assignment like the ane presented hither, which requires students to extract and record specific data from the textbook. Higher-order thinking information technology's not, but it is a helpful incentive to encourage students to open their textbooks and actually comprehend what is written there.

I give students exercise answering questions in depression-stakes ConcepTests (using clickers) or on-line practice quizzes before asking such questions on high-stakes exams. Hither are some sample questions:

Why is information technology hotter at the equator than it is at the poles?

a. Considering the equator is closer to the sunday.

b. Because the sun's rays travel through more temper at the equator.

c. Because the sunday's energy is more spread out at the equator.

d. Because the sun's rays hit the earth's surface at a higher angle at the equator.

e. Because the sun is always directly overhead at the equator.

If the World's axis simply had a 5° tilt, how would the seasons in Chico be different from how they are at present?

a. The seasons would exist shorter.

b. The transitions between seasons would be more abrupt.

c. The dissimilarity in temperature between summer and winter wouldn't be as great.

d. Summertime days would be longer than they are now and winter days would exist shorter than they are now.

e. All of the above.

On exams, I ask students open-ended essay questions (Microsoft Word 4.3MB Sep5 09) that crave them to synthesize the concepts gained from this lab activity.

References and Resources

Gould, A., Willard, C. and Pompea, S., 2004, The Real Reasons for Seasons: Sun-World Connections: GEMS (Great Explorations in Math and Science), Lawrence Hall of Science, Academy of California, Berkeley.

This teacher'due south guide features many engaging hands-on activities. Although it was written for teachers of grades 6-eight, it is also useful for high schoolhouse teachers and college professors.

Schneps, Matthew H., 1989, A Private Universe.

This video was produced by the folks at the Individual Universe Project who studied common misconceptions about the seasons and the phases of the moon. To view this video, whorl to the bottom of the page and click on the "VoD" icon. You will have to commencement annals with the Annenburg Media Center (learner.org) to see the video, but registration is free and it grants yous access to many other videos for educators.

An extension of this activity that helps students deepen their understanding of the concepts is to model the path of the sunday beyond the sky at different latitudes and at unlike times of the year. An excellent cheap solar movement demonstrator kit is available from the Astronomical Club of the Pacific (www.astrosociety.org). I accept written a worksheet for students to complete (Microsoft Word 63kB Sep5 09) equally they work with these solar motion demonstrators.

Go back to the Guided Discovery Bug examples page.

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Source: https://serc.carleton.edu/sp/library/guided_discovery/examples/seasons.html

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