Question

Explain the term water cycle. State the main points to show how water moves from the earth’s surface to the atmosphere and back to the earth’s surface as rain

Answer 1

The water cycle is a natural process by which the circulation of water takes place from the earth’s surface to the atmosphere and back to the earth’s surface as rainwater. The Process of the water cycle is discussed below :
FROM THE EARTH’S SURFACE – TO THE ATMOSPHERE
1. Evaporation — The sun’s rays fall on the earth & warm its surface & the air above it. The heat evaporates the water from the streams, rivers & the sea.
2. Water [mainly in the form of water vapour] is also added to the atmosphere by
(a) Respiration by living organisms Glucose + Oxygen → carbon dioxide + water + energy
(b) Burning of fossil fuels —
Fuel+Oxygen \[\ce{->[heat]}\] carbon dioxide + water +energy.
3 Formation of clouds — The water vapour along with the warm air rises upwards, where at higher altitudes it condenses into small droplets of water forming clouds.

BACK TO THE EARTH’S SURFACE – AS RAINWATER
1. Formation of rain — The clouds float in the atmosphere & when the size of the water droplets increases they fall down on the earth as rainwater.
2. Rainwater falls into streams — The rainwater is absorbed by the soil collects underground & flows into streams.
3. Stream water enters rivers & seas — The stream water finds its outlets into rivers & later enters into the seas & oceans.
4. River & seawater evaporates forming clouds and thus continuing the water.

Answer 2

The water cycle is a natural process by which the circulation of water takes place from the earth’s surface to the atmosphere and back to the earth’s surface as rainwater. The Process of the water cycle is discussed below :

FROM THE EARTH’S SURFACE – TO THE ATMOSPHERE

1. Evaporation — The sun’s rays fall on the earth & warm its surface & the air above it. The heat evaporates the water from the streams, rivers & the sea.

2. Water [mainly in the form of water vapour] is also added to the atmosphere by

(a) Respiration by living organisms Glucose + Oxygen → carbon dioxide + water + energy

(b) Burning of fossil fuels —
\[\ce{Fuel + oxygen ->[heat] carbon dioxide + water + energy}\]
3 Formation of clouds — The water vapour along with the warm air rises upwards, where at higher altitudes it condenses into small droplets of water forming clouds.

BACK TO THE EARTH’S SURFACE – AS RAINWATER

1. Formation of rain — The clouds float in the atmosphere & when the size of the water droplets increases they fall down on the earth as rainwater.
2. Rainwater falls into streams — The rainwater is absorbed by the soil collects underground & flows into streams.
3. Stream water enters rivers & seas — The stream water finds its outlets into rivers & later enters into the seas & oceans.
4. River & seawater evaporates forming clouds and thus continuing the water.