Structure of the atmosphere
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All 15 Flashcards — Structure of the atmosphere
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Question
What is the troposphere?
Answer
The troposphere is the lowest layer of the atmosphere (about 0–12 km) where weather occurs and most water vapour is found.
💡 Hint
Lowest layer + weather.
Question
Which two atmospheric layers are most commonly tested in ESS and why?
Answer
The troposphere (weather, life, greenhouse effect) and the stratosphere (ozone layer, UV protection) are most commonly tested because they directly affect living systems.
💡 Hint
Troposphere + stratosphere.
Question
What is the greenhouse effect (in one sentence)?
Answer
The greenhouse effect is the process where greenhouse gases absorb and re-emit long-wave radiation, warming the lower atmosphere.
💡 Hint
Absorb + re-emit LW.
Question
Give one reason the troposphere is the most important layer for life.
Answer
It contains almost all water vapour and is where weather and atmospheric mixing occur, supporting ecosystems and the water cycle.
💡 Hint
Water vapour + weather.
Question
What is the stratosphere and why does temperature increase with altitude there?
Answer
The stratosphere is the layer from about 12–50 km that contains the ozone layer. Temperature increases with altitude because ozone absorbs UV radiation.
💡 Hint
Ozone absorbs UV.
Question
State one key feature of the troposphere.
Answer
In the troposphere (0–12 km), temperature decreases with altitude and weather occurs.
💡 Hint
Weather + cooling with height.
Question
Explain why atmospheric pressure is important for life on Earth.
Answer
Atmospheric pressure helps maintain liquid water at Earth’s surface; without enough pressure, water would evaporate or freeze more easily.
💡 Hint
Liquid water needs pressure.
Question
State the approximate temperature lapse rate in the troposphere.
Answer
Temperature decreases with altitude by about 6.5°C per km in the troposphere.
💡 Hint
~6.5°C per km.
Question
State one key feature of the stratosphere.
Answer
In the stratosphere (12–50 km), temperature increases with altitude due to UV absorption by ozone.
💡 Hint
Ozone warms stratosphere.
Question
What are the two major gases in the atmosphere (with approximate percentages)?
Answer
Nitrogen (N₂) is about 78% and oxygen (O₂) is about 21% of the atmosphere.
💡 Hint
78/21.
Question
Name three greenhouse gases (trace gases) that strongly influence temperature.
Answer
Carbon dioxide (CO₂), water vapour (H₂O), and methane (CH₄).
💡 Hint
CO2 + H2O + CH4.
Question
Which layer mainly provides UV protection, and how?
Answer
The stratosphere provides UV protection because the ozone layer absorbs harmful UV-B and UV-C radiation.
💡 Hint
Stratosphere = ozone.
Question
Exam skill: How should you structure “how the atmosphere supports life” answers?
Answer
Name a function (e.g., greenhouse effect, ozone absorption, oxygen supply) and immediately link it to an outcome for life (e.g., liquid water, reduced DNA damage, respiration).
💡 Hint
Function → outcome.
Question
Why can trace gases have a large effect on climate?
Answer
Even in small concentrations, greenhouse gases like CO₂, H₂O, and CH₄ absorb and re-emit long-wave radiation, strongly influencing Earth’s temperature.
💡 Hint
Small amount, big impact.
Question
Exam warning: What is the key difference between the greenhouse effect and the ozone layer?
Answer
The greenhouse effect mainly operates in the troposphere to warm Earth by trapping long-wave radiation, while the ozone layer is in the stratosphere and protects life by absorbing UV radiation.
💡 Hint
Different layers, different roles.
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Topic 6.1 hub
Introduction to the atmosphere
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