Starter quiz
- What is a star?
- a huge ball of very hot gas and plasma that is burning
- a huge ball of very hot gas and plasma with a burning core
- a ball of very hot gas and plasma with nuclear fission reactions in its core
- a ball of very hot gas and plasma with nuclear fusion reactions in its core ✓
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- What happens in a nuclear fusion reaction?
- small nuclei combine to form bigger nuclei of the same element
- small nuclei combine to form bigger nuclei of a different element ✓
- large nuclei split to form smaller nuclei of the same element
- large nuclei split to form smaller nuclei of a different element
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- What is a region of space called that contains traces of hydrogen gas and very fine dust?
- 'nebula' ✓
- What is a protostar?
- a huge ball of dense, hot gas ✓
- a huge ball of dense, hot burning gas
- a huge ball of dense, hot gas with nuclear fission reactions in its core
- a huge ball of dense, hot gas with nuclear fusion reactions in its core
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- What type of nuclei (which element) is fused together in nuclear reactions in the core of a new star?
- 'Hydrogen' ✓
- What type of star fuses hydrogen in its core?
- a neutron star ✓
- a main sequence star ✓
- a protostar
- a white dwarf star
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Exit quiz
- What is the main type of nuclear reaction that takes place in the core of a star?
- nuclear fission
- nuclear fusion ✓
- alpha decay
- beta decay
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- How long are very large stars main sequence stars for, compared to average-sized stars?
- for much longer than average-sized stars
- for about the same time as average-sized stars
- for much less time than average-sized stars ✓
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- What causes a star to expand into a red giant star?
- increased temperature throughout the star from hydrogen fusion
- increased temperature in the core of a star from hydrogen fusion
- increased temperature throughout the star from helium fusion
- increased temperature in the core of a star from helium fusion ✓
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- What type of star forms from the core of a red giant star after its outer layers have been lost?
- a white dwarf star ✓
- a white giant star
- a white main sequence star
- a white nebula
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- What happens to the outer layers of a red supergiant star?
- its gravitational force is big enough to hold onto its outer layers
- its outer layers escape very slowly into space
- its outer layers escape fairly rapidly into space
- its outer layers are blasted off into space in an explosion ✓
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- What can form from the core of a red supergiant star after its outer layers have been lost in a supernova explosion?
- a black hole ✓
- a neutron star ✓
- a white dwarf star
- a white giant star
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Worksheet
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Lesson Details
Key learning points
- Radiation pressure from nuclear fusion pushes out from the centre of a star.
- Gravitational force pulls in towards the centre of a star.
- When a star is in balance, forces from radiation pressure are equal in size to gravitational forces.
- A main sequence star is a star in balance for millions of years, until it no can longer fuse hydrogen nuclei.
- After all available hydrogen has been fused, gravity contracts a star raising temperature until other nuclei can fuse.
Common misconception
Stars just exist and do not change over time.
Explain the cause and effect of changes in stars and support pupils in explaining these ideas in their own words.
Keywords
Main sequence star - a star which is fusing hydrogen in its core; these stars are stable for long periods of time
Red giant star - a larger, cooler, star formed after hydrogen in the core has been depleted
White dwarf star - the white hot core of a star after its outer layers have escaped into space
Supernova - an exploding star, caused by a gravitational collapse after the fuel is exhausted
Neutron star - an incredibly dense star, formed after a supernova
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