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Posts Tagged ‘Earth Sciences’

The Total Solar Eclipse and Scientific Literacy

On August 21st, around 1:24 pm Central Standard Time, on the historical Orchard Dale Farm just outside the little hamlet of Cerulean, Kentucky, there will be a few curious humans wearing all manners of strange sunglasses staring up in the sky to witness a once-in-a-lifetime event: a total solar eclipse.

Path of Totality

Animated Video of the Path of Totality (NASA/Goddard Space Flight Center Scientific Visualization Studio)

Unlike the thousands of other eclipse worshipers in the nearby town of Hopkinsville, where there will be a well-planned festival with live music and parades, the few hardcore eclipse fanatics who are precise in their geographical coordinates will visit this farm because it is the spot where the eclipse’s greatest coverage, and one of the longest in duration, can be viewed. A total solar eclipse is where the earth crosses the shadow of the moon, completely obscuring the sun and cutting off all direct rays of sunlight to earth. Stars will appear, the earth will cool, and the moon’s black disk will exhibit a halo around its edge from the sun’s corona.

This spectacular eclipse will be the first total solar eclipse in the United States since 1991 and the first coast-to-coast in nearly 100 years. The path of totality will cast a shadow 70 miles wide and will first present itself on the Pacific coast of Oregon near Salem, and then proceed across the heart of the country before exiting the Atlantic coast near Charleston, South Carolina.

Events like solar eclipses are great teachable moments for educators to not only teach students about eclipses but also for students to become more science literate. Science literate students, whether or not they go on to science-related careers or not, become a more informed public, and a more informed public means better decision making.

One of the goals of science literacy (and by extension, the scientific method) is to describe, explain, and predict natural phenomena. For science educators teaching astronomy, science literacy is not not just about explaining the world around us, but also explaining and predicting the behavior of other objects in our solar system, such as the sun and our moon, and our relationship with those extraterrestrial bodies.

Today, astronomers can now easily predict such things as the precise times and places of various celestial events such as meteor showers, comet visitations, and of course solar eclipses; not only the precise time an eclipse will happen at a particular location, but also where and when the longest duration and greatest extent of an eclipse. eLibrary can assist science teachers toward the goal of helping students become science literate. It has a wealth of information on all things astronomical, including its Research Topic on solar and lunar eclipses. Be sure to check out these and other resources at the end of this blog.

So, where will you be viewing the solar eclipse? Can’t be there? Too far away from the path of totality? For those who can’t watch the eclipse live, you can visit NASA’s Total Eclipse website and view their Eclipse Live Stream page here.

Parisians, circa 1912, Viewing a Solar Eclipse

Parisians, circa 1912, Viewing a Solar Eclipse (Wikimedia Commons)

If you decide to view the total eclipse in person, there are a few safety precautions you should take before attempting it. First, if you plan on looking directly into the sun, be sure you have the proper solar filter sunglasses for viewing. Using anything else will risk severe eye damage or blindness. If you are within the path of totality you may remove your solar filtered sunglasses briefly when the moon completely covers the sun but be sure to replace your solar viewers soon after to watch the departing eclipse. An alternative method for viewing the eclipse is the pinhole projection. Simply punch a hole in an index card or a sheet of cardboard and project an image onto a nearby surface. Alternatively, hold out and cross your hands in front of you with your fingers of both hands slightly stretched open to project the sun onto the ground in front of you and watch the projection of the spaces between your fingers change as the eclipse takes place. For more indepth safety tips for viewing the solar eclipse, visit NASA’s eclipse page on viewing safety here.

Finally, for those of you who plan to view the eclipse along the path of totality: Happy sun gazing and here’s wishing for clear skies!

Here are some eLibrary Research Topics and other helpful articles that will assist you in viewing and understanding the upcoming solar eclipse:

 

Einstein’s General Theory of Relativity Published

Illustration of the Distortion of Space-Time Caused by the Sun's Mass

In April 2004 NASA sent into space the Gravity Probe B satellite on a mission to prove a couple of postulations published 98 years ago this week by a man considered by many the greatest intellectual mind ever. On May 4, 2011, seven years after the probe was launched, the experiments finally confirmed two predictions by Albert Einstein‘s theory of general relativity: the warping, or curving, of space and time (space-time) around Earth; and frame-dragging, the amount of space-time that is dragged around Earth by its rotation. Thursday, March 20th, marks the landmark date when Einstein published those arguments, and others, under his theory of gravity in “The Foundation of the General Theory of Relativity.”

Gravity Probe BEven though Einstein worked these theories out mathematically, to get a practical sense of what these principles meant, there are two analogies most frequently used. First, with the warping of space-time around a large mass, imagine a large, heavy ball (representing the Sun) placed in the center of a thin, stretched sheet of rubber (representing space). The ball presses down in the middle of the sheet causing a depression, or curvature. When another smaller ball (representing Earth) is tossed onto the sheet it will circle and roll toward the larger ball. Einstein posited that gravity was not some mysterious gravitational force, as Isaac Newton thought, but merely smaller objects traveling through space along a curve toward the larger ones with enough mass that warps space around them. With frame-dragging, think of Earth as being immersed in honey. As the Earth rotates, the honey around it would swirl. And so it would with space and time.

Although measuring these two effects by the Gravity Probe B has led to practical applications in the improvement in aeronautics and GPS technologies, for astrophysicists and cosmologists it has fueled further interest in black holes. It is believed that objects with much more mass than our earth or sun can warp space-time fabric so much that they can create a hole where space itself falls into and where even light cannot escape.

Is gravity nothing more than the motion of objects around other, more massive objects which distort and curve the fabric of space-time?  Are there objects so massive where even light cannot escape? To dig deeper into these questions, and more on Albert Einstein and his theory of general relativity, visit eLibrary and view the resources below.

Research Topics:

Albert Einstein
Astrophysics
Black Holes
Gravity
Isaac Newton
Relativity
Space-Time

eLibrary Browse by Topic:

Astrophysics
Black Holes
Cosmology
Light & Special Relativity
Relativity

Global Warming? What Global Warming? It’s Cold Out There!

Pedestrians Brave Record Cold Temperatures

After a week of the coldest temperatures in 20 years people are asking: “Global warming, what are you talking about? It’s colder than a Siberian winter!” Conversely, during the summer when it becomes so hot that it’s unbearable you’ll hear people complain about the impending doom of global warming. And while we here in North America were experiencing record cold, Russia has been experiencing an unusually warm winter.

Climate science is probably one of the least understood of the atmospheric sciences by the public. When extreme weather events or temperature changes occur during a given period, people tend to make instant judgments about global warming. Climate change is a study of weather conditions averaged over a long period of time, not just a week, month, or even one year. In fact, long-term weather phenomenon such as El Niño is not considered climate change. Yet people’s attitudes and beliefs seem to shift with the change in seasons and temperatures.

Rising global temperatureWhen scientists talk about how temperatures have risen about 1.3 degrees Fahrenheit over the past century you may not see that worthy of your attention. However, 1.3 degrees on a global, long-term scale means a lot. At the poles, it can mean the difference between freezing and melting. And for organisms that have carved out a niche and evolved under specific environmental and climatic conditions, two degrees can put added stress on a species.

So, when you start to think about and discuss in class the issues of global warming and climate change remember to keep things in perspective.  Global warming is real, but recent weather conditions or temperatures are not necessarily an indication of long-term climate conditions.

Be sure to check out eLibrary‘s wealth of resources on climate change and global warming in helping you do you research.

Research Topics:

Climate Change
Climatology
Global Warming
Greenhouse Effect

eLibrary Browse by Topic:

Climatology

Reference:

Global Warming and the Greenhouse Effect
Hutchinson Encyclopedia

The Politics of Climate Change
The No-Nonsense Guide to Climate Change (Reference Book)

 

Hurricane Season Begins in June

Hurricane Katrina in the Gulf of Mexico

Hurricane Katrina in the Gulf of Mexico

In June, as the most active part of the tornado season begins to subside, the Atlantic hurricane season begins, with peak season from mid-August through October. Hurricanes, or tropical cyclones, are enormous spiraling tropical storms produced by warm, tropical oceans and a warm, moist atmosphere. They are characterized by 1) the eye, a low-pressure center that is relatively calm; 2) the eyewall surrounding the eye, compact clouds containing the strongest winds; and 3) outer rain bands with strong, tropical force winds and thunderstorms stretching out as far as 300 miles from the eye. Where tornadoes are more compact and direct their damage in a relatively confined area, hurricanes, in contrast, bring destruction to vastly larger areas, as has been seen in recent storms such as Hurricanes Katrina and Sandy.

eLibrary has an array of video and interactive resources for you to learn more about hurricanes.

Cyclone FormationKRT Interactive, 3D Animation, Agence France Presse Animations, as well as Great Events of  the 20th Century provide excellent videos, animation, and interactive resources on a hurricane’s destructive power, the scientific explanations how hurricanes form and their life cycle, and historic review of past individual hurricanes that have hit the United States. Simply perform a Basic Search on hurricanes or cyclones and limit your search to Audio/Video resources. In addition, our Research Topics cover individual hurricanes and a list can be located by browsing eLibrary’s Research Topics.

Other resources:

Browse by Topic:

Hurricanes

Cyclones

Journals:

Bulletin of the American Meteorological Society

Journal of Applied Meteorology

Journal of Applied Meteorology and Climatology

Journal of Climate

Monthly Weather Review

Weather and Forecasting

Weatherwise