AST101H1 Lecture Notes - Lecture 9: Nuclear Fission, Photosphere, Nuclear Reaction
5 Dec 2017
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Diameter: 1,392,000 kilometers (109x diameter of earth) Rotation rate: 25 days (equator) to 30 days (poles) Temp: 5500 c (average) 3700 c (sunspots) 15 million c (centre) Halo of gas above photosphere and chromosphere. Seen only during total eclipse of the sun. A nucleus made of positively charged protons and neutral neutrons. Negative electrons orbiting outside (actually a quantum probability cloud) The electrons determine how a material behaves. Number of protons determines identity (gold- 79, helium 2) Combinations of atoms made by sharing electrons. Electrons in atoms or molecules change over to new partners (nuclei just observe) Fission (e. g. nuclear reactors, atomic bombs) requires heavy elements like uranium, plutonium. Fusion (e. g. hydrogen bombs) uses light elements like hydrogen, helium. Very hard to make happen protons fiercely repel unless they get very close. Heat something up: atoms move faster- at 15 million c, atoms moving so fast that they stick.
