Edexcel GCSE Biology · 1BI0
Specification 6.9, 9.14 · Paper 2
- Revise: Transpiration
The change of liquid water at a surface into water vapour.
- Revise: Water Cycle
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GCSE Biology · key term
The change of liquid water into water vapour.
Used by Edexcel and OCR
Specification 6.9, 9.14 · Paper 2
The change of liquid water at a surface into water vapour.
Specification B3.3b, B4.1c · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
The change of liquid water into water vapour; this requires an energy transfer from the surroundings.
Revise: Control of body temperatureEvaporation requires energy, which is transferred from the skin to the evaporating water. This cools the skin and increases energy transfer from the body. Sweat that runs off without evaporating provides much less cooling, so evaporation is the important step.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
The change of liquid water into water vapour; this transfers thermal energy away from the skin when sweat evaporates.
Revise: Skin and Temperature ControlThe fastest-moving water molecules escape, taking thermal energy from the skin. It is evaporation—not merely the presence of liquid sweat—that produces cooling. Sweating is therefore less effective if sweat cannot evaporate readily.
When explaining the pathway, give the stages in order: absorption at the roots → movement through xylem → evaporation from moist mesophyll-cell surfaces → diffusion through leaf air spaces and stomata.
When explaining the water cycle, link processes with where the water goes: evaporation and transpiration add water vapour to the air; precipitation returns water to the land and sea.
In the water cycle, evaporation produces water vapour; condensation changes water vapour into liquid droplets; precipitation returns water to Earth’s surface.
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