Sources & further reading: https://sites.google.com/view/sourceslargeststar Video on Red Dwarfs: https://www.youtube.com/watch?v=LS-VPyLaJFM&vl=pt What is the largest star in the Universe? And why is it that large? And what ARE stars anyway?

How many planets are in the solar system? How did it form in the Milky Way galaxy? Learn facts about the solar system’s genesis, plus its planets, moons, and asteroids. ➡ Subscribe: http://bit.ly/NatGeoSubscribe #NationalGeographic #SolarSystem #Educational About National Geographic: National Geographic is the world's premium destination for science, exploration, and adventure. Through their world-class scientists, photographers, journalists, and filmmakers, Nat Geo gets you closer to the stories that matter and past the edge of what's possible. Get More National Geographic: Official Site: http://bit.ly/NatGeoOfficialSite Facebook: http://bit.ly/FBNatGeo Twitter: http://bit.ly/NatGeoTwitter Instagram: http://bit.ly/NatGeoInsta Read more in "The solar system, explained" https://on.natgeo.com/2U3E2Be Solar System 101 | National Geographic https://youtu.be/libKVRa01L8 National Geographic https://www.youtube.com/natgeo

Did you know that the Sun’s light shines differently on Earth at different times of the year? In this visualization watch as the Earth orbits the Sun, rotating, like a slightly tilted, spinning top. This rotation changes the angle at which sunlight hits the surface of our planet, creating the different seasons we experience here on Earth. Can you see how sunlight at different times of the year changes the productivity of life on land and in our oceans? Data Sources: Phytoplankton Bloom Imagery: NASA Modis, Land Productivity Data: NASA Modis Land Science Team, NASA Earth Observatory Team, Imagery: Reto Stockli. Ocean Productivity Data: Michael Behrenfeld, Professor Department of Botany and Plant Pathology, Oregon State University, www.science.oregonstate.edu/oceanproductivity. Earth Imagery: NASA Visible Earth. Video Credit: California Academy of Sciences Visualization Studio For classroom activities, visit www.calacademy.org/educators/habitat-earth-in-the-classroom - - - The California Academy of Sciences is the only place in the world with an aquarium, planetarium, natural history museum, and four-story rainforest all under one roof. Visit us online to learn more and to get tickets: http://www.calacademy.org. Connect with us! • Like us on Facebook: http://bit.ly/CASonFB • Follow us on Twitter: http://bit.ly/CASonTwitter • Add us on Google+: http://bit.ly/CASonGoogle

In this episode of Crash Course Astronomy, Phil takes you through the cause and name of the Moon's phases. -- Why the Moon Has Phases 0:36.1 Spheres in Orbit 1:05.4 Name of the Moon Phases 2:25.5 How We See It 7:48.2 -- PBS Digital Studios: http://youtube.com/pbsdigitalstudios Follow Phil on Twitter: https://twitter.com/badastronomer Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Tumblr - http://thecrashcourse.tumblr.com Support CrashCourse on Patreon at http://www.patreon.com/crashcourse -- PHOTOS http://en.wikipedia.org/wiki/Moon#mediaviewer/File:FullMoon2010.jpg https://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=1879 http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0505.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0553.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0634.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0706.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0809.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0905.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.1011.jpg http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.1145.jpg http://en.wikipedia.org/wiki/Moon#mediaviewer/File:NASA-Apollo8-Dec24-Earthrise.jpg http://global.jaxa.jp/press/2008/04/img/20080411_kaguya_01l.jpg http://global.jaxa.jp/press/2008/04/20080411_kaguya_e.html http://www.esa.int/Our_Activities/Operations/First_view_of_Earth_as_Rosetta_approaches_home http://commons.wikimedia.org/wiki/File:Sachin_Nigam_-_starry_moon_%28by-sa%29.jpg https://www.flickr.com/photos/badastronomy/14397419837/

How did everything get started? A nice simple explanation of a complex theory

A cool comparison of the scale of everything in the Universe.

Population, community and ecosystem

With so many organisms on Earth, living things are bound to interact with one another. Symbiosis is a close relationship between two species. One type of interaction between two species is called mutualism. An example of mutualism exists between honey bees and flowers. Flowers provide nectar to the bees. The bees use the sugar rich liquid to make honey. As the bees fly from flower to flower tiny grains of pollen get stuck to the bee. The bee moves the pollen without even knowing it. The pollination is necessary for flowers to reproduce. In this relationship both species benefit. The bee gets nectar and the flower gets pollinated. Another relationship is called commensalism. This interaction takes place when sharks and remora live together. The remora use sucking disks on their heads to attach themselves to sharks. The sharks are powerful swimmers and do not even notice the remora and are neither helped nor harmed. However the remora benefit from this relationship. The fish get a free ride and protection. They also feed on scraps left over by the shark. In commensalism one species benefits and the other is neither helped nor harmed. The last type of symbiotic relationship is called parasitism. An example of this relationship exists between humans and mosquitoes. The insects land on and take the blood from humans. The mosquito benefits as it uses the blood for energy. The human or host is harmed in this relationship as blood is needed and the human could become infected with disease. In parasitism one species benefits and the other is harmed.

This newest science animation is about genes, DNA and Chromosomes. There is SO much more to say about this subject, but I decided to start off with the basics, and I will definitely make another animation on this subject again. Don't hesitate to comment if you it turns out I made an mistake somewhere, or if you want to tell me something else! Animation: Chaja Hogeweg (www.chajahogeweg.com) Voice-over: Adam Janka Software: Adobe After Effects, Adobe Photoshop, Adobe Illustrator, Toonboom Harmony More of this? https://www.youtube.com/watch?v=k71vEXjaPuQ&feature=youtu.be

What are Isotopes? Find out in this video from the Properties of Matter chapter. 00:00:02,590 -- 00:00:07,319 In a previous video we learnt about Isotopes. Here are a few more examples. 00:00:07,319 -- 00:00:14,319 There are two isotopic forms of Chlorine: Chlorine 35 and Chlorine 37. Remember isotopes 00:00:16,910 -- 00:00:21,869 have the SAME number of protons, but a different number of neutrons. So how 00:00:21,869 -- 00:00:27,090 many neutrons are in each of these isotopic forms of Chlorine? 00:00:27,090 -- 00:00:30,980 Remember: Mass Number = Number of Protons + Number of 00:00:30,980 -- 00:00:34,030 Neutrons. And the number of protons for each isotope forms 00:00:34,030 -- 00:00:39,960 of elements is the same, so we can rearrange this formula to calculate the number of neutrons 00:00:39,960 -- 00:00:44,969 in each form. Neutrons = Mass Number - Protons 00:00:44,969 -- 00:00:51,969 When we look at Chlorine on the periodic table it has an atomic number of 17, therefore it 00:00:55,149 -- 00:00:59,860 has 17 protons. So Chlorine-35 has a mass of 35. 00:00:59,860 -- 00:01:04,480 Neutrons = Mass Number - Protons = 35 -17 00:01:04,480 -- 00:01:06,909 = 18 18 neutrons 00:01:06,909 -- 00:01:13,909 So Chlorine-37 has a mass of 37. Neutrons = Mass Number - Protons 00:01:15,360 -- 00:01:18,929 = 37 -17 = 20 00:01:18,929 -- 00:01:24,590 20 neutrons. So Chlorine-35 has 18 neutrons and Chlorine 00:01:24,590 -- 00:01:25,999 37 has 20 neutrons. 00:01:25,999 -- 00:01:32,999 Another example of an isotope is Lithium. Lithium has two stable isotopic forms. 00:01:33,340 -- 00:01:38,619 The atomic number of Lithium is 3, therefore it has 3 protons. 00:01:38,619 -- 00:01:43,450 The isotopes of Lithium have 3 neutrons and 4 neutrons respectively. 00:01:43,450 -- 00:01:48,729 How do we calculate each of the isotopes mass number? 00:01:48,729 -- 00:01:52,349 Remember, Mass Number = Number of Protons + Number of 00:01:52,349 -- 00:01:56,209 Neutrons. So for one isotopic form the mass number would 00:01:56,209 -- 00:02:00,059 be: 3 + 3 = 6 00:02:00,059 -- 00:02:04,489 So we would have Li-6 And for the other form, the mass number would 00:02:04,489 -- 00:02:05,599 be 3+4 = 7 00:02:05,599 -- 00:02:09,580 So we would have Li- 7 Want to learn more? Visit: www.fuseschool.org This video is distributed under a Creative Commons License: Attribution-NonCommercial-NoDerivs CC BY-NC-ND

'The Journey of the Digestive System' by National Geographic