|
Featured Videos
|
|
Not Right For WatchKnowLearn
Ages: 12 - 18
3409 Views:
|
The slipperiest stuff known to man, Teflon has made a tremendous impact on the world. Invented by accident in 1938, it has gone on to become a substance in all kinds of household items. Created by mistake, PTFE (poly-tetra-fluoro-ethylene) is a long... chain carbon polymer surrounded by fluoride atoms. The fluoride atoms fully enclose the carbon chain so that it can't react with other molecules. It wasn't until 1944 that the name "Teflon" became trademarked. Dr. Kiki gives us the skinny in this episode of Food Science.Run time 03:31.
[more]
June 14, 2010 at 02:15 PM
|
|
|
Not Right For WatchKnowLearn
Ages: 12 - 18
9547 Views:
|
The development of measuring systems is a great human accomplishment. The early Egyptians created a unit of length, the cubit, based on the human forearm. The English and others, used the human foot and grains of barley corn to measure length. The m...etric system started with an fascinating attempt to define the meter using time. The meter evolved through a number of incarnations many involving distances taken from the planet. Today the meter is defined using the speed of light. This definition relies on a reliable means for measuring time. Time and space have been joined in our current definition of the meter. (07:23)
[more]
December 5, 2009 at 09:44 PM
|
|
|
Not Right For WatchKnowLearn
Ages: 13 - 18
3862 Views:
|
In this video, Sal Khan demonstrates how to solve for 'x'. Mr. Khan uses software (with different colors) to illustrate his points. Sal Khan is the recipient of the 2009 Microsoft Tech Award in Education. There is a lot of information on the screen--...the viewer may want to open the video to 'full screen.' (03:04)
[more]
June 13, 2010 at 05:25 PM
|
|
|
Not Right For WatchKnowLearn
Ages: 10 - 16
6606 Views:
|
This is a clip from a film documentary with vintage photographs of the famous scientist. (01:35)
July 13, 2009 at 01:14 PM
|
|
|
Not Right For WatchKnowLearn
Ages: 11 - 18
1771 Views:
|
There's a continent called Pangaea?! Well, there once was. Hundreds of millions of years ago, Earth looked completely different from how it does today. All of the land was packed into a single super-continent. Geologist Alfred Wegener theorized that ...this giant landmass split into chunks and slowly drifted apart. Rejected at first by the scientific community, Wegener's theory of continental drift eventually was proved correct: The earth's crust is split up into dozens of pieces called tectonic plates, which "float" on top of the mantle. Warmed by the blazing-hot core, the mantle churns in circular convection currents, dragging tectonic plates along for the ride. Today, plate tectonics is the unifying theory of the entire field of geology. It explains the rock cycle, the origin of Earth's surface features, and the cause of seismic activity, such as earthquakes and volcanoes. Get the drift? Watch this movie to learn more! (07:09)
[more]
May 24, 2018 at 06:03 PM
|
|
|
Not Right For WatchKnowLearn
Ages: 6 - 18
4891 Views:
|
This 2:46 long video reviews some of the Australian Aborigine's culture through the Dreaming Period, when the Earth was given to the humans, according to their beliefs. Excellent video to show this culture.
October 13, 2011 at 02:18 PM
|
|