This video excerpt from NOVA examines a genetic screening technique called preimplantation genetic diagnosis, or PGD. PGD enables researchers to identify mutations in an embryo’s DNA that can lead to birth defects and more than 300 diseases, including Huntington’s, cystic fibrosis, and some cancers. While the technique allows parents who use in vitro fertilization (IVF) to better understand the risk that their child might be diagnosed with a terrible disease, it is also being used in some parts of the world to select for sex. Serious ethical questions are being raised about this use and about the possibility of expanding the list of traits that are screened for. This video is available in both English and Spanish audio, along with corresponding closed captions. Credits: https://www.pbslearningmedia.org/credits/cygc12.sci.life.gen.prediagnosis/ LICENSE: https://www.pbslearningmedia.org/help/full-license-for-section-3c-of-terms-of-use-download-and-share/
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The theory of how the Grand Canyon was formed is shown in this animation from NOVA, and features rare footage of a phenomenon known as debris flow. CREDITS: https://www.pbslearningmedia.org/credits/ess05.sci.ess.earthsys.canyon/ LICENSE: https://www.pbslearningmedia.org/help/full-license-for-secti
In this video from NOVA’s Sun Lab, learn about the Sun’s ever-changing surface and magnetic field. Images and animations illustrate how the Sun’s magnetic field lines are affected by the motion of the Sun’s plasma. Over time, the magnetic field becomes twisted and more complex, which increases solar
In this video from NOVA’s Sun Lab, learn about the Sun’s composition and structure. The Sun is a plasma, primarily made of hydrogen with smaller amounts of other elements. Animations and images illustrate the physical and behavioral properties of the Sun’s six regions: the core, radiative zone, conv
