Notebook Science 노트북 사이언스 · MYP Physical & Earth Sciences 1–3
Unit 12 · Earth & Space

The Atmosphere

대기

What is actually in the air around us, and why is Earth's temperature just right for life?

Big idea Earth's atmosphere is a layered mix of gases that protects us, drives our weather, and keeps the planet warm through the greenhouse effect.

01Composition of the atmosphere

Earth's atmosphere is mostly nitrogen (about 78%) and oxygen (about 21%), with small amounts of argon, carbon dioxide, water vapour and other gases.

02Layers of the atmosphere

The atmosphere is divided into layers based on temperature and height.

  • Troposphere — lowest layer, where we live and where weather happens
  • Stratosphere — contains the ozone layer, which absorbs harmful UV radiation
  • Mesosphere — where most meteors burn up
  • Thermosphere — very thin air, where auroras occur
  • Exosphere — outermost layer, fading into space

03The greenhouse effect

Greenhouse gases (like carbon dioxide, methane and water vapour) trap some of the Sun's heat that would otherwise escape back into space, keeping Earth warm enough to support life.

Human activities (like burning fossil fuels) have increased greenhouse gas levels, strengthening this effect and contributing to global warming.

04Weather and climate

Weather describes the day-to-day conditions in the troposphere (temperature, rain, wind, cloud), while climate describes the average weather pattern of a place over many years.

'Climate change' refers to long-term shifts in these average patterns, not single weather events.

Key vocabulary
Term한국어Meaning
atmosphere대기The layer of gases surrounding Earth
troposphere대류권Lowest atmospheric layer, where weather occurs
ozone layer오존층Stratosphere layer that absorbs harmful UV radiation
greenhouse gas온실가스A gas that traps heat in the atmosphere
greenhouse effect온실 효과Warming caused by trapped heat from the Sun
climate기후The average weather pattern of a place over many years
Quick check — tap a question to reveal the answer
What are the two most common gases in Earth's atmosphere?
Nitrogen (about 78%) and oxygen (about 21%).
Which atmospheric layer contains the ozone layer?
The stratosphere.
What is the difference between weather and climate?
Weather is day-to-day conditions; climate is the average pattern over many years.