Q1.
What do you see when you look up in the sky?
Answer
Floating clouds, the sunshine, and — even if you cannot see it — a breeze you can feel on your face. The chapter's point is that these three are not separate things you happen to notice. All of them are the result of one thing: the blanket of air surrounding the Earth, called the atmosphere.
| What you notice | What it actually is |
|---|---|
| Clouds | Water vapour from the atmosphere that has condensed — and almost all of it sits in the lowest layer, the troposphere |
| Sunshine | Sunlight that has passed through the atmosphere, with the harmful radiation, including ultraviolet, filtered out on the way |
| A breeze | Air on the move — wind, flowing from a high-pressure area towards a low-pressure area |
Why we cannot see the atmosphere itself: the gases that make it up — nitrogen, oxygen, argon — are colourless and transparent. We only ever see what the atmosphere does: the clouds it forms, the light it lets through, the dust it carries, the blue it scatters. That is why the sky looks empty and yet nothing about the sky is empty.