Water Cycle Concepts: Boiling, Condensation, Evaporation

Boiling Point

• Boiling point is the temperature where a liquid turns into a gas.
• Affected by atmospheric pressure.
• Water at sea level boils at 100°C (212°F).
• Higher boiling points require more energy to vaporize.
• Altitude and pressure change boiling points.
• Used to identify substances and in chemical processes.

Condensation

• Condensation is water vapor turning into liquid water.
• A crucial step in the water cycle, forming clouds.
• Occurs as warm air rises, cools, and water vapor condenses.
• Droplets combine to form larger droplets and precipitation.
• Can occur on surfaces (e.g., windows) when surface temperature is below the dew point.

Evaporation

• Evaporation is a liquid turning into a gas due to increased temperature or decreased pressure.
• Essential in the water cycle, contributing to clouds and precipitation.
• Factors affecting rate: temperature, humidity, surface area, and air movement.
• Regulates Earth's temperature by absorbing heat.
• Increased evaporation can lead to water scarcity.

Freezing Point

• Freezing point is the temperature a liquid turns into a solid.
• Water freezes at 0°C.
• Different substances have different freezing points.
• Impurities lower freezing points.
• Pressure and altitude also influence the freezing point.

Melting Point

• Melting point is the temperature a solid turns into a liquid.
• A characteristic property used to identify substances.
• Affected by molecular structure, intermolecular forces, and pressure.
• Remains constant during the phase change.
• Impurities lower the melting point and widen the melting range.

Physical States of Water

• Water exists as solid (ice), liquid (water), and gas (water vapor).
• States depend on temperature and pressure.
• Solid water has a fixed shape; liquid water takes the container shape; water vapor is an invisible gas.
• Solid water molecules are tightly packed with lowest energy.

Water Cycle

• The water cycle is a continuous process of water movement on Earth.
• Driven by solar energy.
• Involves evaporation, condensation, precipitation, and runoff.
• Water vapor forms clouds.
• Precipitation returns water to Earth's surface (rain, snow, etc.).

Energy Absorption

• Energy absorption is taking in and storing energy.
• Essential for organisms' functions: growth, reproduction, metabolism.
• Plants use energy absorption in photosynthesis.
• Earth's surface energy absorption affects global climate.
• Increased absorption from human activities alters the environment (e.g., temperature rise).

Energy Release

• Energy release is converting stored energy into usable forms (e.g., heat, light).
• Different sources release energy (chemical, mechanical, thermal, nuclear).
• Fundamental in natural and industrial processes.
• Examples include combustion, nuclear fission, and biochemical reactions.
• Understanding release is key to energy production and consumption.

Water Vapour

• Water vapor is the gaseous form of water.
• Regulates Earth's temperature by trapping heat.
• A greenhouse gas.
• Influences weather patterns and cloud/precipitation formation.
• Exists in the atmosphere within specific temperature/pressure ranges.
• Changes in water vapor affect climate stability.