Eclipses: The Definitive Facts & Poster

Middle and High School

Eclipses are an awe-inspiring phenomenon. They’re the perfect chance to make science even more fun and exciting for your class! Students will welcome being equipped with the knowledge to describe solar eclipses scientifically. From understanding eclipse types and frequencies to safely observing this celestial spectacle, they’ll be eager to dive into the cosmic wonders that await!

To help you reveal the magic behind solar eclipses, we’ve compiled some stellar facts to support your lesson plans!

Shedding light on eclipse types

Studying eclipses helps us observe the laws of physics governing celestial bodies. Researchers also get a better understanding of Earth’s atmosphere under uncommon conditions. In contrast to the everyday change in the light we see at dusk and dawn, a solar eclipse changes the illumination of Earth and its atmosphere under a relatively small region of the Moon’s shadow. NASA researchers explain that this localized blocking of solar energy helps study the Sun’s effects on the upper atmosphere, where the Sun’s energy creates a layer of charged particles called the ionosphere. 

So, what are the different types of solar eclipses?

Partial Eclipse:
During a partial solar eclipse, the Moon partially covers the Sun when viewed from Earth. As the Moon moves between the Sun and Earth, it casts a shadow on Earth's surface but doesn't fully block the Sun's disc. Instead, a portion of the Sun's light remains visible, resulting in a mesmerizing dance between light and shadow. The amount of coverage varies depending on the observer's location. A partial eclipse is often seen as a crescent shape or as the Moon taking a bite out of the Sun.

Annular Eclipse:
An annular eclipse occurs when the Moon is directly in line with the Sun and Earth but is slightly farther away from Earth. As a result, the Moon appears smaller in the sky, and when it passes in front of the Sun, it doesn't fully cover it. Instead, a ring of sunlight, known as the "annulus," remains visible around the Moon. This creates a mesmerizing "ring of fire" effect. Annular eclipses happen when the Moon is at or near its farthest point from Earth (apogee) and the Earth is at or near its closest point to the Sun (perihelion).

Total Eclipse:
The total solar eclipse is the grand spectacle of celestial events. It occurs when the Moon aligns perfectly with the Sun and Earth, positioning itself to fully block the Sun's dazzling face while darkness briefly takes over the daytime sky. As the Moon passes between the Sun and Earth, it casts a shadow on a specific area on Earth's surface. As the sky darkens, stars may become visible, and the Sun's outer atmosphere, known as the corona, shines brilliantly around the Moon. Total solar eclipses are the most dramatic and captivating, leaving observers in awe of nature's splendor. 

Each eclipse type offers a unique and awe-inspiring experience, showcasing the intricate dance between our celestial neighbors. Whether it's the mysterious crescent shape, the captivating "ring of fire," or the breathtaking darkness of a total eclipse, witnessing these cosmic events will demonstrate the vast wonders of our universe to your students.

Frequency of Eclipses:

Solar eclipses are extraordinary cosmic events, but they don't happen every day. In fact, their infrequency adds to their allure! 

On average, there are about two to five solar eclipses every year, with a total eclipse occurring about every 18 months. Generally, total solar eclipses are visible every 400 years from any one place. Not all eclipses are visible from every location on Earth. Upcoming events include:

• Annular Solar Eclipse: Oct. 14, 2023
• Total Solar Eclipse: April 8, 2024

You can find a complete list of eclipses through 2030 on Nasa’s website here. 

How do clouds affect an eclipse?

During a solar eclipse, the Moon blocks some of the Sun's light from reaching Earth's surface. However, even if the sky is cloudy, some sunlight can penetrate the clouds and reach the Earth. This scattered sunlight can create diffuse illumination in the sky, contributing to shadows.

Clouds act as a diffusing medium, scattering sunlight in various directions. When sunlight passes through clouds, it bounces off the tiny water droplets or ice crystals in the clouds, causing the light to scatter. Some scattered light reaches the ground, albeit with reduced intensity compared to direct sunlight. This scattered light creates an ambient illumination that can cast shadows, even during an eclipse. 

The presence of shadows during a cloudy eclipse may not be as sharp or distinct as on a clear day. However, they can still be noticeable due to the contrast between the darker areas directly under the umbra (the Moon's shadow) and the lighter areas affected by the scattered sunlight. *

Students may be interested in knowing that the visibility of shadows during an eclipse can also depend on the thickness and density of the clouds. And the type and size of the particles or molecules involved in scattering determine the specific characteristics of the scattered light, such as its intensity, color, and direction. So, thicker clouds with greater coverage may significantly reduce the amount of sunlight reaching the ground, resulting in dimmer light conditions and less pronounced shadows. 

If you need more facts for your lesson plan, we’ve got you totally covered in our previous post, Eclipse Science Facts.

* Wearing specialized eye protection is a must when viewing an eclipse. This is true even if the sky is cloudy on the day of the big event.

Eclipse Viewing Guide:

Once your students grasp the different types and frequencies of solar eclipses, they’re ready to explore how to observe them safely. Safety is paramount when watching an eclipse, as looking directly at the Sun can cause severe eye damage. However, fear not, for we have some tips to ensure a safe and captivating viewing experience:

Safety comes first, last, and always. The Sun is an intriguing sphere of scorching, swirling gases; its surface can be highly captivating to observe. However, there are many inherent risks associated with observing the Sun that everyone must be conscious of—particularly during a solar eclipse. The Sun's ultraviolet and infrared rays can harm the eyes’ retinas, resulting in vision loss and permanent blindness!

When observing the Sun during an eclipse or any other instance, your primary focus should always be safeguarding your eyes. As long as you meticulously adhere to all the regulations and recommendations, solar viewing is secure—making solar viewing an educational and fun experience for all.

So, Print and share these Warnings, Rules, And Guidelines For Safe Solar Observing.  

Eclipse Glasses:
Get special-purpose solar eclipse glasses for your students. This essential product will safely engage students with a once-in-a-lifetime astronomical event. No greater opportunity will inspire young scientists to partake in the celestial relationship between the Earth, moon, and sun. ISO 12312-2 approved lenses equipped with filters that block harmful ultraviolet and infrared rays, allowing only safe levels of sunlight to reach the eyes. Remind your students to wear these glasses throughout the entire eclipse. 

White Light Solar Filters: 
A white light solar filter that works in the visible spectrum is an ideal way to turn a nighttime astronomical telescope into a daytime solar observing telescope. It is designed to view the solar photosphere and sunspots. Solar filters can be metal on glass (the most durable and costly), aluminized polyester film (also known as aluminized Mylar), and polymer. They feature Solar Safe filter technology, the ultimate protection from harmful solar radiation, including I.R. and U.V. light, and 99.999% of visible light.

Solar Safe Binoculars:
EclipSmart Solar Binoculars are compact and easy to transport while traveling to a solar eclipse viewing location. These white-light solar viewing binoculars provide a full, magnified view of the entire solar disk. They also feature Solar Safe filter technology for the ultimate protection from harmful solar radiation, including both I.R. and U.V. light and 99.999% visible light.

Dedicated White-Light Solar Telescope:
Celestron's EclipSmart Travel Solar Scope 50 is a true white-light solar scope for the observer on the go. It's lightweight, compact, and easy to transport while traveling to a solar viewing event. It's an ideal instrument for viewing the solar photosphere and sunspots. The 50mm refracting solar scope uses Celestron's Solar Safe, ISO-compliant, full-aperture glass filter material to ensure the safest view. This solar scope offers much higher magnifications for viewing sunspots or planetary transits than you would otherwise get using solar eclipse glasses or binoculars.

Pinhole Projection:
Creating a pinhole projector is a simple and fascinating way to witness an eclipse. Instruct your students to punch a small hole in a piece of cardboard and hold it up, allowing the sunlight to pass through the hole and project onto a surface, such as a sheet of white paper. You can also lead students through the creation of their own pinhole camera with this basic construction kit. These methods create a mesmerizing image of the eclipse safely, without direct exposure to the Sun.

Interlacing Fingers:
No additional equipment is required for this indirect viewing method. Just interlace your fingers, leaving small gaps between them. Stand with your back towards the Sun and allow sunlight to pass through your fingers and onto the ground. During the partial phases of a solar eclipse, you can see tiny crescents being projected.

Tree Leaves (nature’s pinhole):
Yet another indirect method of viewing the partial phase of a solar eclipse is to allow nature to play a role. Sunlight filtering through tree leaves will create countless crescent Sun images on the ground or a wall. In an annular eclipse, you can see many circle-like shadows with bright rings during maximum coverage. It truly is a sight to see!

Live Streaming and Online Resources:
If direct observation isn't possible due to geographical limitations or weather conditions, fear not! NASA provides live streams of eclipses, offering an opportunity to witness the spectacle remotely. Utilize their online resources to bring the awe-inspiring event to your students, even if you're miles away. NASA Solar Eclipse Partner Locations for 2023 and 2024.

Studying solar eclipses provide invaluable opportunities for students to investigate the Sun, Moon, and Earth's interactions, shedding light on the fundamental principles of orbital mechanics, celestial alignments, and the behavior of light. Use your lesson plan to inspire future generations of astronomers, scientists, and explorers to unravel the mysteries of the universe.