The rock cycle in three journeys
No rock is permanent. Given enough heat, pressure or weather, any rock can become another kind — and it does, over and over.
Part of your national curriculum
- Chemistry: Earth and atmosphere: Understand the composition of the Earth and its atmosphere, and the rock cycle and the formation of igneous, sedimentary and metamorphic rocks
Lesson overview
What you'll learn in this lesson
Understand the composition of the Earth and its atmosphere, and the rock cycle and the formation of igneous, sedimentary and metamorphic rocks
Key learning points
- • Inside the Earth
- • Three rock types
- • The cycle
This lesson at a glance
- 25 minutes
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
The rock cycle in three journeys
No rock is permanent. Given enough heat, pressure or weather, any rock can become another kind — and it does, over and over.
In a nutshell
Understand the composition of the Earth and its atmosphere, and the rock cycle and the formation of igneous, sedimentary and metamorphic rocks
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Inside the Earth
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
Inside the Earth
A thin rocky crust sits on the hot mantle, which surrounds a liquid outer core and a solid inner core of iron and nickel. Today's atmosphere is roughly 78% nitrogen and 21% oxygen, with small but important amounts of carbon dioxide and water vapour.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 20
Learn
Three rock types
Igneous rock forms as molten rock cools; slow cooling underground grows large crystals, fast cooling at the surface leaves small ones. Sedimentary rock forms as fragments settle in layers and are compacted and cemented, sometimes trapping fossils. Metamorphic rock forms when heat and pressure change an existing rock without melting it.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · The cycle
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
The cycle
Weathering and erosion break rock into sediment; burial compacts it; deeper burial cooks it into metamorphic rock; deeper still it melts and returns as igneous rock when it cools. Uplift can return any of these to the surface to start again.
Quick check
Part 11 of 20
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 13 of 20
Explore the idea
Part 14 of 20
Worked example
Worked example: identifying a rock
A sample contains visible shell fragments in layers and fizzes with dilute acid. Conclusion: it is sedimentary, most likely a limestone. Fossils survive only where rock never melted, and layering points to sediment settling — both rule out igneous and metamorphic origins.
Challenge round
Part 15 of 20
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 17 of 20
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Today's ____ is roughly 78% nitrogen and 21% oxygen, with small but important amounts of carbon dioxide and water vapour.
____ rock forms as molten rock cools; slow cooling underground grows large crystals, fast cooling at the surface leaves small ones.
____ rock forms as fragments settle in layers and are compacted and cemented, sometimes trapping fossils.
Challenge round
Part 18 of 20
Game · Recall cards
Which rock type forms from cooling magma or lava?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: The rock cycle in three journeys
4 questions, marked with the reasoning shown. No timer.
1. Which rock type forms from cooling magma or lava?
2. Which gas makes up the largest percentage of today's atmosphere?
3. How does marble form from limestone?
4. Which rock type can contain fossils?
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
Quiz score
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Points this lesson
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Best run
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Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 20 · Watch & discover
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Understand the composition of the Earth and its atmosphere, and the rock cycle and the formation of igneous, sedimentary and metamorphic rocks