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Flip to reveal answersWhy is water described as Earth’s “thermostat”?
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All 10 Flashcards — The water cycle as a system
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Question
Why is water described as Earth’s “thermostat”?
Answer
Because water absorbs, stores, and redistributes heat, reducing temperature extremes and helping stabilise climate.
💡 Hint
Stabilises temperature.
Question
What percentage of Earth’s water is in oceans, and what percentage is freshwater?
Answer
About 97% is in oceans (saltwater) and about 3% is freshwater.
💡 Hint
97% saltwater.
Question
Explain how high specific heat capacity helps oceans regulate climate.
Answer
Water can absorb a lot of heat energy with only a small temperature rise, so oceans act as heat sinks that buffer daily and seasonal temperature changes.
💡 Hint
Absorb lots of heat with little change.
Question
Define “aquifer”.
Answer
An aquifer is an underground rock layer that stores water in pores and cracks.
💡 Hint
Underground store.
Question
Define “residence time” in a water store.
Answer
Residence time is how long water remains in a store before moving to another part of the system.
💡 Hint
How long it stays.
Question
How does latent heat transfer regulate climate?
Answer
Evaporation absorbs latent heat (cooling) and condensation releases latent heat (warming), moving energy around the atmosphere.
💡 Hint
Evap cools, cond warms.
Question
Give one example of how ocean currents affect climate.
Answer
Ocean currents redistribute heat from the tropics to higher latitudes; for example, warm currents can raise temperatures in nearby coastal regions.
💡 Hint
Move heat poleward.
Question
What is the difference between infiltration and percolation?
Answer
Infiltration is water soaking into the soil surface. Percolation is water moving downward through soil/rock to groundwater or aquifers.
💡 Hint
Into soil vs down to aquifer.
Question
Why can groundwater become effectively non-renewable?
Answer
If extraction exceeds recharge, aquifers can take centuries to refill, so water can run out within human lifetimes.
💡 Hint
Pump faster than refill.
Question
How does albedo link ice/snow to climate regulation?
Answer
Ice and snow have high albedo so they reflect more solar radiation (cooling). When ice melts, darker water absorbs more radiation (warming).
💡 Hint
White reflects; dark absorbs.
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Full study notes for The water cycle as a system
Topic 4.1 hub
Water systems
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