Rain is falling liquid water droplets from atmospheric condensation. Formation depends on temperature, pressure and humidity. Water cycle involves evaporation, condensation and precipitation
Evaporation occurs when liquid molecules escape from surface into gas phase. Only fraction of liquid molecules have enough energy to escape. Evaporation reduces liquid temperature through evaporative cooling. Process continues until equilibrium between evaporation and condensation
Climate change has intensified the water cycle since at least 1980. Warmer atmosphere contains more water vapor, affecting evaporation and rainfall. Temperature increase by 1°C raises saturation vapor pressure by 7%
Hydrosphere is Earth's combined mass of water on, under, and above surface. Earth's hydrosphere has existed for about 4 billion years. Total water volume is 1.386 billion cubic kilometres. Saltwater comprises 97.5% of total water, fresh water 2.5%
Water cycle is continuous movement of water on, above and below Earth's surface. Earth's total water mass remains constant, but water distribution varies. Ocean holds 97% of Earth's water, source of 86% of global evaporation
Transpiration is water movement through plants and evaporation from aerial parts. Plants lose 97-99.5% of water through transpiration and guttation. Water moves through xylem by cohesion and adhesion to foliage. Stomata control water loss through opening and closing