For a teacher, it is important to bring real-world experiences and events to the students in the classroom.  These teachable moments happen every day.  With access to social media and 24-hour news, it is easy to find information to share and use with your students.  These can range from small, local events to larger, national or international ones.  There is a wonderful teachable moment occurring on August 21, 2017 in all North America…a solar eclipse.

What is a solar eclipse?

A solar eclipse is a celestial event in which the moon passes directly between the Earth and the sun.  The sun is much larger than the moon, but they appear to be about the same size as we observe them, due to the sun’s being about 400 times further away from the Earth..  As the moon passes in front of the sun, it casts a shadow on the Earth.  The fully shaded area of the moon’s shadow is known as the umbra.  The partially shaded area from the shadow is the penumbra.  In a total eclipse, the moon completely covers the sun, while in a partial eclipse only part of the sun is blocked. During a total eclipse, observers will witness the solar corona as a bright area circling the moon. This event can last up to 3 hours, with most places being able to see the eclipse for approximately 1 to 3 minutes.  

How often do they occur?

Total eclipses are not as rare as one might believe.  A total solar eclipse occurs approximately every 18 months on some part of the Earth.  What is rare is how often the same location will witness a solar eclipse.  Many areas go centuries between total solar eclipses.  For example, the last time Atlanta, Georgia experienced a total solar eclipse was June 24, 1778, and it will not experience another until May 11, 2078.   The last one that was visible to parts of the United States occurred on February 26, 1978, but this was only witnessed by those in the northwestern states and Canada.  The next total solar eclipse to travel across parts of the Unites States (from Texas to Maine) will occur on April 8, 2024.

Who will be able to see this eclipse on August 21, 2017?

screen-shot-2017-08-07-at-3-16-46-pmOn this day, parts of South America, Africa, and Europe will be able to see at least a partial eclipse, while all of the United States will be able to witness between 75% and 100% of the eclipse.  You must be in the thin path of totality if you want to witness the total solar eclipse. The path of totality is only about 70 miles wide, and it will start on the West Coast and extend to the East Coast.  The path of totality will extend from Lincoln Beach, Oregon (starting at 9:05 am PDT), across the United States to Charleston, South Carolina (starting at 2:48 pm EDT).  Carbondale, Illinois will witness the longest duration where the totality will last 2 minutes and 40 seconds.

What are some of the teachable moments from the eclipse?

Science: This should be the most obvious one.  This is a great time to discuss the science behind an eclipse.  Use models and flashlights to help, if available.  If not, have the students draw and color pictures.  There are also some good vocabulary terms to introduce (e.g., corona, umbra, penumbra, etc.).  This is also a good time to talk about lunar phases, orbits, and even the solar system in general.

Math: There is lots of good numerical data that can be incorporated into your lessons.  Distances from the Earth to the sun vs. the distance from the Earth to the moon, for example Also, the diameter of the sun, earth, and moon can be used to show how the width of path of totality.  Students can also do graphing of distance vs. time, to help see how fast the eclipse will travel across the United States.  

Language Arts and Social Studies:  Students can write eclipse poems, or such as haikus.  There are books that have “eclipse” as their focus, such as American Eclipse, by David Baron or Mask of the Sun: The Science, History and Forgotten Lore of Eclipses. by John Dvorak.   There are also many myths and superstitions associated with an eclipse.  Anything from dogs trying to steal the sun on orders from a king (Korea), to a frog that eats the sun (Vietnam), and even that the sun and moon are fighting (the Batammaliba, Africa).  See if the students can create and share their own “myth” behind an eclipse.

It is important to remember not to look directly at the eclipse, as it will cause damage to your eyes.  Many schools, museums, and libraries have a limited supply of the special glasses you need to view the eclipse.  You can also purchase them through many online retailers. This is a rare celestial event that may not come by a city near you for many years to come.  Enjoy the day!

About the Author
A former science teacher in Georgia, Dr Michael Tolmich is now USATestprep’s Science Content Team Leader. He lives with his wife and their two sons in Tucker, GA.