IGCSE 0625 / Section 6.2.2 / Extended
Supplement (Extended) content

Born, lived, gone.

Stars are born in clouds and die in two very different ways. A star like the Sun fades quietly to a glowing ember, while a giant goes out in a single colossal explosion, leaving something far stranger behind.

The key idea

A star forms from a nebula collapsing under gravity into a protostar, then a stable star powered by fusion. A Sun-like star later swells into a red giant and ends as a white dwarf, while a much more massive star becomes a red supergiant, explodes as a supernova, and leaves a neutron star or a black hole.

Definition · learn the exact words

A star forms from a cloud of gas and dust (a nebula) that collapses under gravity into a protostar, becoming a stable star when fusion begins.

Sun-like: red giant → white dwarf

Massive: red supergiant → supernova → neutron star or black hole. The ending depends on the star’s mass.

Section 01

Follow a star’s life.

Watch a star form, live, and end in one of two ways depending on its mass.

Stage 1 · Learn

Check star life cycle

Four quick checks. Each correct answer earns XP and lights this skill on your star map.

Quick check+10 XP

A star forms from a cloud of gas and dust called a...

Quick check+10 XP

Before nuclear fusion begins, the collapsing cloud is a...

Quick check+10 XP

A star like the Sun finally ends its life as a...

Quick check+10 XP

A much more massive star ends its life in a...

Section 02

Two endings, set by mass.

A Sun-like star fades to a white dwarf; a massive star explodes as a supernova.

Star like the SunMuch more massive star
Nebula, then protostar, then stable starNebula, then protostar, then stable star
Swells into a red giantSwells into a red supergiant
Sheds its layers, leaving a white dwarfExplodes as a supernova
Ends as a white dwarfLeaves a neutron star or a black hole
Examiner trap

How a star ends depends on its mass. A star like the Sun becomes a red giant then a white dwarf, but a much more massive star explodes as a supernova and leaves behind a neutron star or a black hole.

Stage 2 · Exam

Exam-style questions

Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.

Finish the four checks above to unlock the exam questions
Exam style+20 XP

What determines whether a star ends as a white dwarf or as a supernova?

Exam style+20 XP

After a supernova, the remaining core may become...

Exam style+20 XP

Which sequence is correct for a star like the Sun?

Skill unlocked

Star life cycle, mastered.

The life cycle of a star is mapped. Keep the chain going.

-Rank -Level -Score -Topics
Go deeper · practice
Six original Cambridge-style questions
The stages of a star from nebula and protostar to the white-dwarf or supernova endings set by mass. Attempt each, then reveal the worked solution.
Stage 3 · master the unit
Space physics challenge
Mixed questions across the whole unit, each one worth XP. Start this only when you feel confident across every topic in the unit, not just star life cycle.
Start the unit challenge →