Stars WJEC Physics Unit 2 2 5 WJEC
- Slides: 6
Stars WJEC Physics Unit 2 - 2. 5 WJEC Science (Double Award) Unit 6 - 6. 4
Stars A hot star A cold star • We can work out what a star is made from by looking at the light that comes off it. • As light passes through a prism, a spectrum is produced. Missing parts of the spectrum appear as black lines, and correspond to the elements in the atmosphere of the star. • We have found that Hydrogen and Helium are the elements found in the atmosphere of stars.
THE LIFE OF A STAR • The Sun is at a stable point in its life, 4. 5 billion years old! • The internal forces due to the nuclear fusion reaction, balance the gravitational force. • What happens next?
THE LIFE OF A STAR • The internal forces increase, as the pressure inside the star increases, and the star will expand. • The energy is now spread over a larger surface area, and the overall temperature of the star will be less – a Red Giant is formed.
THE LIFE OF A STAR • There will be nothing to fuel the nuclear fusion reaction as the Hydrogen and Helium come to an end. • The force of gravity will become more significant, and the outer layers of the star will be blown away into space by radiation pressure, leaving a small dense core – A White Dwarf
The Life of a Star Our Sun cooling Red dwarf Dense star Black dwarf explosion Very dense star cooling Supernova cooling Red dwarf Black hole • It is possible for a number of things to happen to the White Dwarf – it depends on the star’s density.
