A Journey through States of Water – CBSE NCERT Study Resources

The water cycle is the continuous movement of water between Earth's surface and the atmosphere. Our textbook shows it includes evaporation, condensation, and precipitation.

• Evaporation: Water turns into vapor from oceans.
• Condensation: Vapor forms clouds.
• Precipitation: Rain or snow falls.

It maintains water balance by recycling freshwater. For example, NCERT mentions how rivers refill due to rain.

Evaporation is liquid turning to gas, while condensation is gas turning to liquid.

• Evaporation: Occurs when water heats (e.g., drying clothes).
• Condensation: Happens when vapor cools (e.g., dew on grass).

NCERT shows evaporation in salt pans and condensation in cloud formation.

Water expands on freezing because its molecules form a hexagonal structure, increasing volume.

This unique property is due to hydrogen bonding. NCERT explains it using ice cubes floating in water.

It insulates lakes, protecting fish. For example, polar ecosystems rely on this.

Sublimation is solid turning to gas, while deposition is gas turning to solid.

• Sublimation: Dry ice vanishes without melting.
• Deposition: Frost forms on cold surfaces.

NCERT mentions camphor subliming. Deposition is seen in winter window frost.

Latent heat is energy absorbed/released during state change without temperature change.

Water absorbs heat to evaporate. NCERT shows steam burns worse than boiling water due to extra latent heat.

This explains why sweating cools us—heat is used for evaporation.

Evaporation is liquid turning to gas, while condensation is gas turning to liquid.

• Evaporation needs heat (e.g., drying clothes).
• Condensation needs cooling (e.g., dew on grass).

Our textbook shows seawater becoming salt-free via evaporation. At home, condensation forms on cold drink bottles.

Ice floats because it is less dense than liquid water.

• Water expands on freezing, reducing density.
• This creates gaps in ice’s structure.

Our textbook mentions icebergs floating. In winter, lakes freeze top-down, protecting aquatic life.

Sublimation is solid turning directly to gas, while melting needs a liquid stage.

• Camphor sublimes (NCERT example).
• Wax melts to liquid first.

Dry ice (solid CO₂) sublimes in fog machines. Wax candles melt when lit.

Humidity is air’s water vapor content. High humidity slows evaporation.

• NCERT shows wet cloths drying slower in humid areas.
• Dry air absorbs moisture faster.

Clothes dry faster in summer than monsoon. Desert air evaporates sweat quickly.

The water cycle is the continuous movement of water between Earth's surface and the atmosphere. We studied that it includes evaporation, condensation, and precipitation.

Water evaporates from oceans, forms clouds, and falls as rain. Our textbook shows how plants contribute through transpiration.

In nature, this cycle refills rivers and lakes. Farmers rely on rain for crops.

Evaporation is when water turns into vapor, absorbing heat. We learned it causes cooling.

Our textbook shows sweating cools our body as sweat evaporates. This uses body heat.

Earthen pots cool water by letting it evaporate through tiny pores, just like NCERT’s matka example.

Condensation occurs when water vapor cools and turns to liquid. We studied it forms dew.

At night, grass loses heat, cooling nearby air. NCERT’s ice-water jar experiment shows droplets forming outside the jar.

Dew helps plants survive dry spells by providing morning moisture.

Ice floats because it is less dense than water. We learned water expands when freezing.

NCERT explains that hydrogen bonds in ice create space, making it lighter than the same volume of water.

Lakes freeze top-down, protecting aquatic life underneath.

Both change water to vapor, but boiling is faster and needs heat. Evaporation happens slowly.

NCERT’s kettle shows bubbles during boiling, while evaporation occurs at any temperature, like drying clothes.

Boiling sterilizes water, while evaporation dries wet floors naturally.

The water cycle is the continuous movement of water on, above, and below the Earth's surface. It involves several key processes:

• Evaporation: The sun heats water in rivers, lakes, and oceans, turning it into water vapor that rises into the air.
• Condensation: As the vapor cools high in the atmosphere, it forms tiny water droplets, creating clouds.
• Precipitation: When these droplets become heavy, they fall back to Earth as rain, snow, or hail.

This cycle ensures a constant supply of fresh water for plants, animals, and humans. A labeled diagram would show:
1. The sun heating water bodies (evaporation).
2. Clouds forming (condensation).
3. Rain falling (precipitation).
4. Water flowing back into rivers and oceans (collection).

Without the water cycle, life on Earth would not be possible as it replenishes our water sources naturally.

Water exists in three states—solid, liquid, and gas—depending on temperature:

• Solid (Ice): Below 0°C, water freezes into ice. Example: Glaciers and snow-capped mountains store freshwater.
• Liquid (Water): Between 0°C and 100°C, water remains liquid. Example: Rivers and oceans support aquatic life.
• Gas (Vapor): Above 100°C, water boils into vapor. Example: Steam from geysers or hot springs.

These changes are crucial because:
1. Melting of ice provides water during summers.
2. Evaporation helps in cloud formation for rain.
3. Freezing protects aquatic life by insulating water bodies in winter.

Understanding these states helps us predict weather patterns and manage water resources effectively.

The water cycle, also known as the hydrological cycle, is the continuous movement of water on, above, and below the Earth's surface. It involves several key stages:

• Evaporation: The sun heats water in rivers, lakes, and oceans, turning it into water vapor.
• Condensation: The water vapor rises, cools, and forms tiny droplets that gather to form clouds.
• Precipitation: When the clouds become heavy, water falls back to Earth as rain, snow, or hail.
• Collection: Water collects in oceans, lakes, and rivers, or seeps into the ground as groundwater.

This cycle ensures a continuous supply of fresh water for plants, animals, and humans. A labeled diagram would show arrows connecting these stages, illustrating the cycle's endless nature.

Freezing and melting are changes in the state of water due to temperature variations:

• Freezing: When water cools below 0°C, it turns into ice (solid).
  Example: Formation of glaciers or ice cubes.
• Melting: When ice is heated, it turns back into liquid water.
  Example: Ice melting in a drink or snow melting in spring.

These processes impact the environment and daily life:
Environmental Effects: Glaciers melting due to global warming raise sea levels.
Daily Life: Freezing preserves food, while melting provides water for crops.

Freezing and melting are processes that change the state of water between liquid and solid.

• Freezing: When water loses heat energy (cooling below 0°C), it turns into ice, a solid state. Example: Water in a freezer forms ice cubes.
• Melting: When ice gains heat energy (warming above 0°C), it turns back into liquid water. Example: Ice cream melts on a hot day.

These processes are essential in nature. For instance, glaciers melt to provide rivers with water, and freezing helps preserve food. Understanding these changes helps us predict weather patterns and manage resources.

Evaporation and condensation are key processes in cloud and rain formation. Here’s how they work:

Evaporation: When the sun heats water bodies, water turns into vapor and rises into the atmosphere. For example, puddles dry up after a sunny day due to evaporation.

Condensation: As the vapor rises, it cools and condenses into tiny droplets around dust particles, forming clouds. You can see this when steam from a hot drink condenses on a cold window.

When these droplets grow heavy, they fall as rain. This is why we often see rain after cloudy days. These processes are essential for weather patterns and water supply.

Condensation is the process where water vapor cools and changes back into liquid water. This occurs when warm, moist air rises and meets cooler air, causing the vapor to form tiny droplets.

Its importance in the water cycle includes:
1. Formation of clouds, which lead to precipitation.
2. Helps distribute water across different regions, maintaining balance in nature.

Two real-life examples of condensation are:
1. Dew on grass: On cool mornings, water vapor in the air condenses on grass blades.
2. Foggy mirrors: After a hot shower, steam condenses on the cooler mirror surface, forming droplets.