THE SUN by cormac ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a A BIG FAT BALL OF Hydrogen AND Helium en-us 2018-01-09 08:15:12 UTC 2018-01-29 14:31:29 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Rocket.png the sun is a star cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219631938 2018-01-09 08:20:57 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219631938 it is made of of 72% H, 26% He and 2% other cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632336 2018-01-09 08:22:54 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632336 One million Earths could fit inside the Sun cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632727 2018-01-09 08:24:37 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632727 The Sun contains 99.86% of the mass in the Solar System. cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632796 2018-01-09 08:24:56 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632796 The Sun is an almost perfect sphere. cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632971 2018-01-09 08:25:45 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219632971 The temperature inside the Sun can reach 15 million degrees Celsius cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219633105 2018-01-09 08:26:14 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219633105 Eventually, the Sun will consume the Earth. cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219633257 2018-01-09 08:26:49 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219633257 The Sun will one day be about the size of Earth cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219633404 2018-01-09 08:27:25 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219633404 1rst comment cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219635456 8 comments late

]]> 2018-01-09 08:36:23 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219635456 LIFE CYCLE OF A STAR • Stars form when enough dust and gas (mainly hydrogen and helium) from space are pulled together by gravitational attraction. Smaller masses may form and be attracted by a larger mass to become planets, or even stars. • During the ‘main sequence’ period of its life cycle, energy is released by the fusion of hydrogen nuclei to make helium nuclei in the core and a star is stable because the forces within it are balanced. The term ‘radiation pressure’ will not be required. • The core (centre) of a star is where the temperature and density are greatest and where most nuclear fusion takes place. • The more massive a star, the hotter its core and the heavier the nuclei it can create by fusion. • Stars change over time; they have a life cycle. This life cycle is determined by the mass of the star. • A main sequence star uses nuclear reactions to produce light and heat. When it runs out of hydrogen, what happens next in its life cycle depends upon its mass. • A larger star will swell to become a red supergiant, in which helium nuclei fuse to form carbon, followed by further fusion that produces heavier nuclei such as nitrogen and oxygen. It expands, cools and turns red. The outer layers then blast away as a supernova is formed. The core collapses and depending upon mass, it forms either a neutron star or a black hole. • A smaller star, similar to our Sun, follows a different sequence, expanding to become a red giant. It then sheds out layers of gas, exposing the core as a white dwarf and finally cools to become a black dwarf. Students should be familiar with charts that show the life cycles of stars. • Fusion processes in stars are the source of energy and produce all of the naturally occurring elements. These elements may be distributed throughout the universe by the explosion of a massive star (supernova) at the end of its life. Students should be able to explain how stars are able to maintain their energy output for millions of years, why the early universe contained only hydrogen but now contains a large variety of different elements and that elements heavier than iron are formed in a supernova. cormac_ruane https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219637933 2018-01-09 08:47:14 UTC https://padlet.com/cormac_ruane/3za0b7d4qw5a/wish/219637933