Science Class 8
Our Home: Earth, a Unique Life Sustaining Planet
Why Earth has life: its place, air, water, soil, and how life goes on.
13 lessons · ~68 min total
Track progress — 0 of 13 lessons read 0%
Lessons in this topic
- 0 Start here Why Earth, of all the planets, has life: distance, size, air, water and soil. · 3 min You are here
- 1 A place in the middle Earth is at the right distance from the Sun for water to stay liquid. · 5 min
- 2 The blanket of air Earth is big enough to keep its air. The air keeps us warm and blocks harmful rays. · 6 min
- 3 Water everywhere Water covers about 70 per cent of Earth. Rain and snow keep it moving. · 5 min
- 4 The thin layer on top Soil forms slowly from broken rock and the remains of living things. · 5 min
- 5 The neighbours Mercury, Venus and Mars differ from Earth in air and heat. · 5 min
- 6 Several at once, not one Life needs the right distance, the right size and a magnetic field, all together. · 6 min
- 7 Checkpoint Five quick checks on distance, air, water, soil and the neighbours. · 4 min
- 8 Looking after Earth Burning fuel adds carbon dioxide and warms the planet. We can use less. · 6 min
- 9 One parent or two One parent makes young that match it. Two parents make young that usually differ. · 7 min
- 10 From flower to seed Pollen moves to a flower. Then gametes join, and the ovule becomes a seed. · 5 min
- 11 The big picture Nine ideas about why Earth supports life and how life goes on. · 4 min
- 12 Track quiz A cheat-sheet of the nine rules, then twelve questions on our home planet. · 7 min
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