Understanding Seasonal Change, Polar Extremes in Seasons, and the Aurora: Content Knowledge for Teachers

For as long as humans have inhabited the earth, knowledge of the regularity of the seasons and day and night has been used to enhance the quality of life. Changing of the seasons was marked with elaborate celebrations around four important dates: the vernal equinox, summer solstice, autumnal equinox and winter solstice. Key weather events such as thunderstorms, tornadoes, drought, hurricanes or blizzards were explained through myths involving supernatural powers. No longer are such explanations sufficient. Science relies upon empirical evidence rather than faith in mythical stories for explanations of seasons, weather-related phenomena, and phases of the moon. For example, we know the tilted earth’s axis and the resultant angle of incidence of the sun’s rays at the poles as compared to the equator, in combination with the earth’s revolution about the sun, are responsible for the seasons. Auroras are visible as functions of the atmospheric content in combination with electromagnetic radiation. The resources listed below will allow you to develop your content knowledge regarding seasons, seasonal change in the Arctic and Antarctica, and the aurora (northern and southern lights).


Seasons

A Reason for the Seasons
Although this is actually a lesson, the background information is helpful in enhancing teacher content knowledge.

Misconceptions About Why Seasons Occur
This pdf is the teacher background piece to a lesson plan. It contains links to two clips from A Private Universe, an educational research video that revealed college graduates’ misconceptions regarding the seasons.

Seasons
A Flash animation shows the earth orbiting the sun and gives dates for the seasons. In addition, it shows the declination of the sun throughout the year, as well as how a constant beam of sunlight gets spread out and concentrated as the sun changes altitude. The resource is from Demonstrations and Animations for Teaching Astronomy (DATA), a web site developed at the University of Illinois.

Observe Seasonal Changes in the Amount of Sunlight Reaching Locations on Earth
This animation demonstrates how the tilt of the earth’s axis causes seasonal variations in daylight. The introduction explains how the images, captured from a geostationary satellite positioned over Australia, were recorded daily from January to December. Learners are instructed to look for the continent of Australia and to play the animation until they can identify the images that represent solstices and equinoxes. Movie controls allow learners to repeat, pause, or step through the animation.

Seasons of the Year
This site contains several concise, illustrated informational pages. Use the left navigation bar to go to other topics such as the angle of sunlight or latitude and longitude.

What Causes Earth’s Seasons?
A graphic illustrates the way solar waves get diffused when they hit closer to the poles, complementing the resource listed above.


Temperature, Weather, and Latitude

Why Is It Warmer at the Equator than at the Poles?
Although this is a commercial site, the answer is brief and on target.

Antarctic Weather
This page contains weather data along with other useful information. A concise explanation for the extreme cold of Antarctica is presented. Live weather data from any of 14 stations is available in the right margin. Also available is a wind chill calculator and a temperature conversion tool.

Arctic Climatology and Meteorology Primer for Newcomers to the North
This is a nicely organized tutorial with sections titled: Basics of Arctic Weather, Factors Affecting Arctic Weather and Climate, Artic Weather Patterns. Each section is further subdivided and easily navigated via the left navigation bar.


The Aurora

Aurora
This brief page shows two photos by a professional photographer who talks briefly of the aurora at both poles.


National Science Education Standards: Science Content Standards

A study of seasons and astronomy aligns with the Earth and Space Science content standard of the National Science Education Standards:

K-4 Earth and Space Science

Objects in the Sky

  • The sun, moon, stars, clouds, birds, and airplanes all have properties, locations, and movements that can be observed and described.
  • The sun provides the light and heat necessary to maintain the temperature of the earth.

Changes in the Earth and Sky

  • Weather changes from day to day and over the seasons. Weather can be described by measurable quantities, such as temperature, wind direction and speed, and precipitation.
  • Objects in the sky have patterns of movement. The sun, for example, appears to move across the sky in the same way every day, but its path changes slowly over the seasons. The moon moves across the sky on a daily basis much like the sun. The observable shape of the moon changes from day to day in a cycle that lasts about a month.

5-8 Earth and Space Science

Structure of the Earth System

  • Clouds, formed by the condensation of water vapor, affect weather and climate.
  • Global patterns of atmospheric movement influence local weather. Oceans have a major effect on climate, because water in the oceans hold a large amount of heat.

Earth in the Solar System

  • The sun is the major source of energy for phenomena on the earth’s surface, such as growth of plants, winds, ocean currents, and the water cycle. Seasons result from variations in the amount of the sun’s energy hitting the surface, due to the tilt of the earth’s rotation on its axis and the length of the day.

Read the entire National Science Education Standards online for free or register to download the free PDF. The content standards are found in Chapter 6.)


This article was written by Mary LeFever. For more information, see the Contributors page. Email Mary at beyondpenguins@msteacher.org .

Copyright May 2008 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license

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