This video segment adapted from NOVA scienceNOW examines a developing theory that might explain a 250-million-year-old "murder mystery." While several possible causes have been considered for the mass extinction that occurred at the end of the Permian period, the scientists featured in the video think a chain of events, beginning with massive volcanic eruptions, might have made Earth uninhabitable for a significant number of terrestrial and marine organisms. According to their theory, these eruptions released gases that warmed both the atmosphere and the oceans. This warming in turn created ideal conditions for killer bacteria to poison the environment. This video is available in both English and Spanish audio, along with corresponding closed captions. CREDITS: https://www.pbslearningmedia.org/credits/oer09.sci.life.evo.massextinct/ 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
