What do the WJEC space topics (2.5 and 2.6) cover?

Topic 2.5 Stars and planets covers the structure of the solar system, the difference between stars and planets, how a star is kept stable by the balance of gravity and radiation pressure, and the full life cycle of stars for both low-mass and high-mass stars. Topic 2.6 The Universe covers red shift, the evidence for an expanding Universe, the Big Bang theory and the cosmic microwave background radiation.

What is the difference between a low-mass and a high-mass star's life cycle?

Both begin as a nebula, form a protostar and join the main sequence. A low-mass star like the Sun then becomes a red giant and ends as a white dwarf. A high-mass star becomes a red supergiant, explodes as a supernova, and leaves a neutron star or a black hole. The mass of the star decides its fate.

How does red shift support the Big Bang?

Light from almost all galaxies is red shifted, meaning their wavelength is increased because they are moving away. More distant galaxies show a greater red shift, so they recede faster, showing the Universe is expanding. Tracing the expansion backwards leads to the Big Bang, and the cosmic microwave background radiation is the leftover radiation that confirms it.

How is the space topic examined?

It sits in Unit 2 (Forces, Space and Radioactivity), a 1 hour 45 minute written paper worth 80 marks and 45% of the GCSE. Expect descriptions of the solar system, the balance of forces in a star, the ordered stages of a star's life cycle, and explanations of red shift and the evidence for the Big Bang.

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WJEC GCSE Physics space and the Universe overview

An overview of the space topics (2.5 and 2.6) in Unit 2 of WJEC GCSE Physics (3420), mapping the solar system and stars, the life cycle of stars, and the Universe with red shift and the Big Bang, and how each part is examined.

Generated by Claude Opus 4.87 min readWJEC 3420 Unit 2.5-2.6Updated 2026-06-14

Reviewed by: AI editorial process; not yet individually human-reviewed

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The topics 2.5 and 2.6 content
How the space topic is examined
How to study the space topic
For the official specification

The space topics (2.5 and 2.6) of WJEC GCSE Physics (specification 3420) are about the solar system, the life and death of stars, and the structure and origin of the Universe. They are examined in Unit 2 (Forces, Space and Radioactivity). This page maps the topics and links to a focused answer page for each part.

The topics 2.5 and 2.6 content

The solar system and stars: The structure of the solar system, the difference between stars, planets, moons and other bodies, and the balance of gravity and radiation pressure that keeps a star stable. See The solar system and stars.
The life cycle of stars: Star formation from a nebula, the main sequence, and the different fates of low-mass and high-mass stars. See The life cycle of stars.
The Universe and red shift: Red shift of light from distant galaxies, the expanding Universe, the Big Bang theory and the cosmic microwave background. See The Universe and red shift.

How the space topic is examined

These topics sit in Unit 2, a written paper of 1 hour 45 minutes, worth 80 marks and 45% of the GCSE, tiered into Foundation and Higher. Expect descriptions of the solar system, explanations of the balance of forces in a stable star, ordered accounts of a star's life cycle, and explanations of red shift and the evidence for the Big Bang.

How to study the space topic

Learn the order. Star life cycles are sequence questions, so learn the stages in order for both low-mass and high-mass stars.
Mind the mass. The fate of a star depends on its mass; do not mix the two routes.
Balance the star. A stable star balances inward gravity against outward radiation pressure from fusion.
Tie red shift to expansion. Longer wavelength means moving away; greater red shift means faster and more distant.
Quote two pieces of Big Bang evidence. Red shift (expansion) and the cosmic microwave background.

For the official specification

WJEC publishes the full specification, past papers and mark schemes at wjec.co.uk. Always revise from the current specification and WJEC's own past papers, because question style, tiering and the formula list are board-specific.

Sources & how we know this

WJEC GCSE Physics specification (3420) from 2016 — WJEC (2016)