Written by: Suzanne Monir, Kimberly Tran, EIS Education Team Members, July 2016
Title: Solar Eclipses
Grade (Age) Level: High School (Ages 14-18), University
Pre-requisites: Knowledge of space at the grade 9 level is recommended.
NASA's official webpage containing information about previous and upcoming solar eclipses.
By inputting your city/town, this calculator will let you know when upcoming solar/lunar eclipses will occur.
This website by Southern Illinois University has information about upcoming solar eclipses in the United States of America along with a countdown clock until the next eclipse.
Parts of a Solar Eclipse
Penumbra- The Moon’s faint outer shadow
Umbra- The Moon’s dark inner shadow
Corona- The gaseous envelope of the sun and other stars. The sun’s corona is only visible during a total solar eclipse when it is seen as an irregularly shaped pearly glow surrounded by the darkened disk of the moon
Difference between Solar and Lunar Eclipse
Phases of the Moon
The moon has eight phases, with the moon orbiting the Earth once every 29 and a half days. Note, when the illuminated part of the moon is getting bigger, the Moon is waxing. When it is getting smaller, the Moon is waning.
The cycles are as follows:
- New Moon: The illuminated side of moon is facing away from the Earth (nothing
- Waxing crescent: Less than half of the illuminated side of the Moon is facing
the Earth (right crescent visible)
- First quarter: Half of the illuminated side of the Moon is facing the Earth
(right half visible)
- Waxing gibbous: More than half of the illuminated side of the Moon is facing
the Earth (right side visible)
- Full moon: The illuminated part of the Moon can be fully seen
- Waning gibbous: The illuminated part of the Moon begins to shrink, with more
than half facing the Earth (left side visible)
- Last quarter: The illuminated part of the Moon shrinks, with half facing the
Earth (left half visible)
- Waning crescent: The illuminated part of the Moon shrinks, with less than half facing the Earth (left crescent visible)
- New Moon: The illuminated side of moon is facing away from the Earth (nothing is seen)
A solar eclipse occurs when the moon passes directly between the Sun and the Earth, resulting in a shadow being cast over the Earth. Solar eclipses only occur during the new moon phase and based on alignment, there are four possibly types of solar eclipses that can be seen. This phenomenon lasts a few minutes and on average occurs every 18 months.
Solar eclipses are the product of coincidence. The Sun with a diameter of 1.39 million kilometers is 400 times larger than the moon with a diameter of 3,474 kilometers. However, the moon is roughly 400 times closer to the Earth than the Sun (384,400 km vs 149.6 million km). Something else to note is that the moon has been gradually moving away from the Earth since its formation billions of years ago. At its current distance, the moon is at the perfect position to appear in the sky as the exact same size as the Sun to block it out.
In this video by Andy Cohen of TED-Ed, what a solar eclipse is and how it is formed is discussed.
Partial solar eclipses
Annular solar eclipses
This activity by McGraw Hill Education will allow students to interact with various factors in the formation of solar eclipses.
You should never view a solar eclipse with unprotected eyes. Staring directly at the Sun can result in retinal burn and blindness. This is because the Sun is too bright for the human eye to handle. During a total eclipse while the Sun is covered by the Moon, it is still dangerous to view unprotected. As a total solar eclipse makes the surrounding area dark, the human pupil dilates to allow more light in for a clearer picture. However the Sun may come out and 'surprise' viewers before they can turn away, making the resulting retinal burn even more dangerous with the eyes trying to let in as much light as possible.
- CDs or Computer floppy discs
- Medical x-ray film with images on them
- Colour film
- Smoked glass
This video by Videofromspace shows how to make an inexpensive projector
Aluminizied Mylar Sheeting/ Solar filters
Aluminized mylar sheeting can be used as a filter to view a solar eclipse. It is easy to cut and attach to a box or viewing device. Alternatively, solar filters can be bought. These filters may be made form aluminized mylar or other material.
In this activity, students will research and share some findings on a solar eclipse that has happened in the past.
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