This mini-lesson takes you through the KS3 chemistry topic Earth and atmosphere: the structure of the Earth, the air we breathe, the rock cycle, our limited resources and recycling, the carbon cycle, and how human activity is changing the climate.
Work through each screen, answer the questions as you go, and collect ⭐ stars. Press Start when you're ready.
Cut the Earth open and you find three main layers, plus the thin skin of gas around it — the atmosphere:
Key idea: the crust is thin compared with the layers below — like the skin on an apple. The mantle is by far the thickest layer, and the core (mostly iron and nickel) is the hottest.
The atmosphere is the layer of gases held around the Earth by gravity. Most of the air is nitrogen, not oxygen:
Common mistake: many people think the air is mostly oxygen because that's the gas we breathe in. In fact nitrogen makes up nearly four-fifths of the air — oxygen is only about a fifth.
The crust is made of rock, and all rocks fall into three families depending on how they formed:
Memory hook: Igneous = ignited/fire (cooled melt); Sedimentary = settled layers; Metamorphic = meta means "changed".
Rocks are not permanent — over millions of years they are turned from one type into another. This is the rock cycle:
Common mistake: a rock's type is not fixed forever. Given enough time and the right conditions, any rock can be turned into a different type — that's the whole point of the rock cycle.
Tap the way each rock type forms.
The Earth gives us useful raw materials — metals from ores, fossil fuels (coal, oil, gas), and materials for glass, plastics and building. But most of these are limited: once used, they are gone or take millions of years to replace.
Key idea: because these resources are non-renewable, we need to use them carefully so future generations still have some.
Recycling means using an old material again instead of throwing it away and digging up new raw material. It is often efficient — it saves resources and usually uses less energy.
But it's not free: recycling still needs energy to collect, clean, sort and melt materials — and some things (like certain plastics) are hard to recycle well. That's why "reduce" and "reuse" matter too.
Carbon is constantly moved between the air, living things and the ground. This is the carbon cycle:
Key idea: naturally the carbon cycle stays roughly balanced — the CO₂ taken out roughly equals the CO₂ put back.
People add extra carbon dioxide to the air, mainly by burning fossil fuels (coal, oil and gas) in power stations, cars and factories, and by cutting down forests (fewer trees to take CO₂ in).
Common mistake: CO₂ does not "burn" the Earth or make a hole in anything — it traps heat. More CO₂ means more heat trapped, which raises average temperatures. That is climate change.
Tap a card, then tap the box it belongs in.
Structure of the Earth: crust (thin) → mantle (thickest) → core (hottest, iron/nickel).
Atmosphere: ≈78% nitrogen, ≈21% oxygen, ≈1% other gases.
Rock types: igneous (cooled melt), sedimentary (squashed layers), metamorphic (heat & pressure).
Rock cycle: any rock can change into another type over time.
Resources: most are limited/non-renewable; recycling saves energy & raw materials.
Carbon cycle: photosynthesis takes CO₂ in; respiration & burning give it out.
Climate: burning fossil fuels adds extra CO₂, which traps heat and warms the Earth.
You've covered the whole KS3 "Earth and atmosphere" topic. Press Finish to see your score.
You've worked through Earth & Atmosphere for KS3 Science. 🎉
Your stars: 0 / 0
Next: test yourself in the Evaluate stage Confidence Quiz, then lock it in with Verify.