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Featured Videos
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Not Right For WatchKnowLearn
Ages: 11 - 18
2360 Views:
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Watch the development of an unborn baby from the moment of conception to birth and beyond. No Narration. The images are set to music and mark the development of the baby by weeks (6 weeks, 8 weeks, 11 weeks etc.) Run time 04:31.
April 7, 2009 at 06:27 AM
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Not Right For WatchKnowLearn
Ages: 10 - 18
1506 Views:
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Excellent video on finding and assembling a Dinosaur skeleton including steps taken to crate bones that are missing.
Summary
The rocks where fossils are found can be soft and crumbly or very hard.
Often both the rocks and the fossilized bones c...ontain minerals that
help protect the bones from weathering. Exposed bone, however, is
sometimes very fragile. To prevent the bones from breaking,
paleontologists, the scientists who study dinosaurs, use certain
procedures to protect a fossil during its excavation and shipment to the
laboratory. Once a specimen has been carefully exposed and examined for
minerals, it is prepared for removal. First, the fossil is brushed
with a type of glue or plastic and then covered with strips of wet paper
and burlap dipped in Plaster of Paris for protection and support. The
most critical part of this preparation is when the fossil has to be
carefully turned over and the underside is also covered and protected.
After the plaster sets, the fossil is numbered and examined to determine
what structural part of the animal has been recovered. Back in the
laboratory, each bone is cleaned and strengthened. Knowledge of today's
animals' skeletons can help the scientists investigate the dinosaur's
remains. By comparing features of bones, a paleontologist may be able
to identify the fossil and its function. Bones along the back, from the
skull or in the jaw are very distinctive and often used to identify the
fossil's remains. Most or all of the skeleton can then be pieced
together if enough bones have been found. Paleontologists may have to
estimate the size and shape of missing bones to complete a full
skeleton. Once all the pieces are identified, a model of the animal is
built to assist the scientist in rebuilding the entire skeleton. Then a
large metal framework is welded together to support the fossilized
bones. The bones are then free mounted to the framework. If a simpler
mount is desired, scientists will fasten the fossils to a slab and use a
bas-relief mounting. Bas-relief mountings display the fossil as it was
buried. Either method preserves the dinosaur's structure for further
observation and research.
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April 16, 2012 at 09:44 AM
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Not Right For WatchKnowLearn
Ages: 9 - 15
1299 Views:
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Everything you ever wanted to know about the Palm Springs or any other windmills, but were afraid to ask. KESQ-TV's Gil Diaz goes behind the locked gates to reveal the "Secrets of the Windmills". Video gives specifics of the wind mill, 228 feet tall... and blades nearly 100 feet long. There are about 4,800 wind mills, they were first installed in 1981, they installed as an experiment by NASA. Where they are installed is the second most consistently windy place in the world, the first is in Africa. The wind turbines generate enough 140,000 to 190,000 homes. The cost of one wind turbine is about $1.5 million. People who live near-by do not like them, but comment that they are a benefit. Somewhat poor quality of video but information is good. Good for middle elementary grade students. Run time 03:29.
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July 24, 2009 at 06:25 AM
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Not Right For WatchKnowLearn
Ages: 10 - 18
1507 Views:
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Glacial Melting
From NationalGeographicVideo, produced by National Geographic
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Disappearing Alpine glaciers are a sign of global warming. In this movie learn how Austria's Goldberg Glacier is shrinking. You can see first-hand a valley that once was completely covered by ice that is now a barren, rocky wasteland with a small str...eam running through it. Run time 02:41.
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April 22, 2009 at 01:46 PM
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Not Right For WatchKnowLearn
Ages: 10 - 18
2520 Views:
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An English teacher explains how to make a complex sentence using an independent and a dependent clause.
August 14, 2009 at 11:04 AM
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