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New
Year 11
OCR
Higher

Birth of a star

I can describe what a star is and how it forms.

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Share activities with pupils
New
New
Year 11
OCR
Higher

Birth of a star

I can describe what a star is and how it forms.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. The Sun is a medium sized star that emits radiation as a result of nuclear fusion reactions in its core.
  2. A star is formed from a cloud (nebula) of dust and gas pulled together by gravitational attraction.
  3. Dust in a nebula is any sort of fine particle, such as specks of rock, and most of the gas in space is hydrogen.
  4. As a star forms, dust and gas accelerate towards its centre over a very long time, creating very high temperatures.
  5. A star forms when hydrogen nuclei in a protostar fuse together converting mass into gamma radiation that causes heating.

Common misconception

The Sun is not a star.

Compare the properties of the Sun with those of stars to show they are similar.

Keywords

  • Star - a ball of very hot gas and plasma that emits radiation and is powered by nuclear fusion in its core

  • Nuclear fusion - the process of merging small nuclei into larger nuclei with the release of energy

  • Nebula - a region of space containing traces of gas (mostly hydrogen) and dust

  • Protostar - a dense, hot, ball of gas formed by a collapsed nebula

  • Main sequence star - the stable period of a star when it is fusing hydrogen in its core

An internet search for ‘the formation of stars’ will help you find videos with animations or simulations of how stars are formed and their life cycles, which you can show to your pupils to stimulate and focus discussion.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Which of these statements about the Sun are correct?
The Sun is a planet.
Correct answer: The Sun is a star.
The Sun is a huge ball of gas and the gas is burning.
Correct answer: Nuclear reactions in the Sun make it hot and bright.
Q2.
What shape are stars?
Correct answer: all stars are approximately spherical
all stars have points and are ‘star-shaped’
some stars are spherical, and some are ‘pointy’ and ‘star-shaped’
stars have a range of different shapes, including spherical and ‘star-shaped’
Q3.
What would the Sun look like if it were two times further away?
the same size and more yellow
smaller and more yellow
the same size and the same colour
Correct answer: smaller and the same colour
Q4.
Why do stars appear to move across the night sky, with their movement repeated once each day?
they orbit Earth once each day
they orbit the Sun once each day
the Earth orbits the Sun once each day
Correct answer: the Earth spins round once each day
Q5.
Why can you only see stars at night?
all of the stars are on the far side of Earth, away from the Sun
Correct answer: light from the Sun makes the whole sky brighter than individual stars
stars only appear at night
stars are not so bright during the day
Q6.
Match each object in space to the correct description.
Correct Answer:planet,a large spherical object that orbits a star

a large spherical object that orbits a star

Correct Answer:star,a very hot ball of gas and plasma that emits light radiation

a very hot ball of gas and plasma that emits light radiation

Correct Answer:galaxy,a group of billions of stars clustered together in space

a group of billions of stars clustered together in space

Correct Answer:universe,the whole of space and everything in it

the whole of space and everything in it

Exit quiz

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6 Questions

Q1.
How does the size of the Sun compare to the size of other stars?
it is smaller than most
Correct answer: it is similar to the average size
it is bigger than most
all stars are about the same size
Q2.
The Sun is one of about 300 billion stars in the galaxy.
Correct Answer: Milkyway, milky way
Q3.
What sort of reaction inside the core of a star causes it to become very, very hot?
a chemical reaction
a nuclear fission reaction
Correct answer: a nuclear fusion reaction
Q4.
What is a nebula typically made of?
Correct answer: hydrogen gas
a mixture of gases (air)
Correct answer: fine dust
rocks
Q5.
A huge spinning ball of very hot, dense gas that forms from a collapsing nebula is called a .
Correct Answer: protostar, proto-star, proto star
Q6.
Put each stage in the early life of a star in the correct order, starting with the first.
1 - A nebula is disturbed and starts to collapse.
2 - Gravitational forces accelerate particles of gas and dust towards each other.
3 - The particles move faster as they come together and the nebula heats up.
4 - A hot dense spinning ball of dust and gas forms, which is called a protostar.
5 - If nuclear fusion begins in the core, it becomes a star.