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Learn how the mix of saltwater and freshwater in the San Francisco Bay affects its diverse ecosystems with John Largier, professor of coastal oceanography at the University of California, Davis. Essential, explosive sodium is a soft, silvery alkali metal that roils in water, releasing clouds of hydrogen gas that fan its yellow flames. It reacts with most elements, and is naturally found only in compounds, such as sodium chloride, or common salt. Ancient Egyptians knew sodium from natron, a mix of salts prized for cleaning, personal hygiene, and preservation, particularly in mummification. Humphry Davy first isolated the element from caustic soda in 1807, naming it sodium; Jakob Berzelius preferred natrium, hence its symbol (Na). As a metal, liquid sodium cools nuclear reactors, and sodium-vapor lamps bathe streets at night in yellow, monochromatic light. In this video, Exploratorium Senior Scientist Paul Doherty explains why we don't have a total solar eclipse every month. A total solar eclipse happens when the moon crosses between the sun and Earth and casts its shadow onto our planet. But the orbit of the moon is tilted relative to the orbit of the Earth around the sun, so the moon often passes below or above Earth. At those times, it does not cross the line between the sun and the Earth, and therefore does not create a solar eclipse. There are just two times a year in the Earth's orbit when there is a possibility of a total solar eclipse.
Join Exploratorium astronomer Isabel Hawkins, and Exploratorium educator Liliana Blanco as they explain the celestial mechanics of a total solar eclipse. Through demonstrations, they show how the moon, sun, and Earth align to create the cosmic coincidence that we see as a total solar eclipse. The Exploratorium is sending a production crew thousands of miles by plane and by boat to Woleai, Micronesia, to broadcast a solar eclipse live to the world. Many factors went into choosing a destination for the broadcast. Executive Producer Robyn Higdon looked along the path of totality for this eclipse, which will start in Indonesia and sweep across the Pacific Ocean, to find a location with good weather predictions and solid land for setting up the telescopes. The Woleai Atoll in Micronesia was the perfect choice. Tune in on March 8th at 5:00 p.m. PST to watch the live broadcast! Learn how to cast images of the sun using nothing more than a piece of paper and your hands! Check out this D.I.Y. video on how to build your own sun viewer using items that you may have lying around your house. All you need is a pair of binoculars, a tripod, and a large piece of white paper or fabric to project the solar image onto.
This is the method used by Galileo himself!
There are many ways that you can safely enjoy a partial or total solar eclipse using items from around your house! Dr. Paul Doherty will show you a few of the easiest methods for safe solar viewing. Neon is normally odorless and colorless, reacting with no one, not even itself. Abundant in the universe, uncommon on Earth, it drifts aloof from any bond. When isolated by Sir William Ramsay and Morris Travers inside a vacuum tube in 1898, the noble gas betrayed its excitement in brilliant red. That excitement, glowing within Georges Claudes ingeniously curved lamps since 1923, has captured our imaginations ever since. Dr. Paul Doherty will give you a demonstration on how the sun can burn a hole in your retina if you don't take the proper procausions when viewing a Solar Eclipse. Remember: Never look directly at the sun, even during a Partial Eclipse!
To learn more about eclipses and safe viewing techniques, check out the various articles and videos on our Eclipse website.