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Water is an important means for survival and no life would exist on Earth without water. Our world is known as the "Blue Planet" because water appears blue from space; it occupies 71% of the earth's surface, and when observed from a distance, water has a bluish reflection. Lakes and rivers cover nearly one percent of the earth's surface. The water in the oceans is saline. It's useless for land-based life. Life on land necessitates the presence of freshwater. On land, rainfall is the primary source of fresh water. As a result, we only have access to 1% of the world's water for our domestic and agricultural needs.
Read Also: Oxygen Cycle
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Definition and Explanation of Water
Two hydrogen atoms and one oxygen atom make up the chemical molecule water. The term "water" usually refers to the compound's liquid state. The solid phase is referred to as ice, whereas the gas phase is referred to as steam. Water can also produce a supercritical fluid under specific conditions.
Water is very essential because it makes up the majority of an organism's body. But, exactly, what is water? A skeleton exists inside the body of a human being, which keeps the body firm and allows one to stand up without collapsing. Water has a skeleton of its own. It, like every other thing on the planet, is made up of small particles called atoms. The hydrogen atom is one of them, while the oxygen atom is the other. As you are surely aware, the air we breathe contains oxygen. A molecule is a single water particle. When a large number of water molecules combine, we can see the water and drink it or use it in other ways, such as flushing a toilet.
Forms of Water
On Earth, water comes in three forms: solid, liquid, and gas.
- The solid component is made up of ice caps in the poles or other snow-covered mountains.
- The liquid component is made up of rivers, lakes, and oceans.
- The gaseous component is made up of water vapor in the atmosphere.
There is a continual flow of water between the earth and the atmosphere in nature. The water cycle, also known as the hydrological cycle, is the process through which water is distributed throughout the biosphere.
Forms of Water
This cycle is crucial in determining a location's weather pattern as well as the global climate.
Read Further Topics:
Water Cycle
The water on the earth's surface is constantly evaporating. The rate of evaporation of water is accelerated by the Sun's heat. When evaporated water reaches the atmosphere, it condenses into droplets due to the cooler air. Clouds are formed when the droplets clump together. When clouds become too thick to retain any more water, water droplets fall as rain on the Earth. This is referred to as precipitation. It vanishes once it lands on the ground.
This process keeps repeating itself in a never-ending circle. The water cycle is often known as the hydrological cycle. The water cycle ensures that all living organisms have access to water and controls our planet's weather patterns.
The main driving forces of the water cycle are the sun’s heat and gravity
Water Availability in Nature
Over 71 percent of the earth's surface is covered by water. As a result, our planet is often known as a watery planet.
Nearly 97.5% of the water available on the planet's surface is held in the seas and oceans. Because it cannot be consumed directly, this water is salty and unfit for human consumption. A major portion of the remaining 2.5% (1.7%) is frozen in the form of ice caps on mountain peaks and glaciers.
Only 0.8% of all freshwater is found in rivers. Human intake of lakes and groundwater is also possible.
Read Also: Dioxygen
Water Resources
Water covers over three-quarters of the earth's surface. Rainwater and surface water, such as river water, lake water, ocean, and groundwater, are two major sources of water on the planet.
| Rainwater | Rainwater is thought to be the finest type of natural water. However, chemicals such as sulfur dioxide and nitrogen dioxide released by automobiles, industry, and other sources mix with the air, making rainfall acidic. |
|---|---|
| Snow | Water is found frozen in the form of snow. |
| Surface Water | Water appears on the earth's surface in the form of snow, river water, and seawater. |
| Seawater | Have you ever had the pleasure of tasting seawater? It's salty (salty). The river water that flows into the sea contains a considerable amount of salt, making it saline. |
| Water from rivers and lakes | Snow melts into liquid water, which then flows into lakes and rivers. Rivers, lakes, and ponds are also flooded by rainwater. The water in rivers, lakes, and ponds is unfit for human consumption. Germs and other soluble contaminants may be present. It can induce gastroenteritis, typhoid, diarrhea, and other waterborne infections if ingested. |
| Groundwater | Groundwater hides a lot of unnoticed water. Groundwater is the liquid that exists beneath the surface of the earth. Rainwater forms it as it seeps through several layers of porous rock and collects in the impermeable layer of rock. Infiltration is the method through which it makes its way to this stratum. The water table is the groundwater's highest point. We use this water by drilling wells or pumping it up from the ground. An aquifer is formed when groundwater is stored between two layers of hard rock. |
Conservation of Water
A global water crisis is now posing a serious threat to the lives of millions of people. With changing climatic conditions, rising population, and dwindling rainfall in many locations, now is the time to get to the bottom of the problem and devise solutions to control it. Water is a valuable commodity. We must conserve water today to make it readily available for future generations.
Points to Remember
- Without water, there can be no life on Earth.
- Water covers 71 percent of the earth's surface and has a bluish reflection when viewed from a distance.
- Oceans cover more than 70% of the earth's surface, whereas land accounts for about 30%.
- Water is made up of small particles called atoms, just like every other thing in the world.
Check out Important Topic: Specific Heat Capacity of Water
Sample Questions
Ques: The United Nations recommends a minimum of .................. per person per day for drinking, washing, cooking and keeping proper hygiene. This equates to around ................... buckets of water per person every day. (2 Marks)
- 50 liters, two and a half
- 25 liters, two and a half
- 55 liters, three and a half
- 70 liters, one and a half
Ans: Option 'a' is the correct answer. The United Nations recommends a minimum of fifty liters of water per person per day for drinking, washing, cooking, and keeping appropriate hygiene. This equates to around two and a half buckets of water per day per person.
Ques: What is the source of the energy that drives the water cycle? (2 Marks)
- It comes from the seas.
- It's caused by rain.
- Option a and option b are both viable options.
- It is derived from the sun.
Ans: Option ‘d' is the correct answer.
The sun provides the energy that spins the water between the oceans, atmosphere, and land. The sun heats the water in rivers, ponds, and oceans on Earth. This water vaporizes and disperses into the atmosphere (atmosphere).
Ques: hich of the following is a process in which water vaporizes in the atmosphere? (1 Mark)
- Evaporation
- Transpiration
- Precipitation
- Condensation
Ans: Option ‘a' is the correct answer. Evaporation is the process of turning water into vapors.
| Components of Ecosystem | Food Chains and Web |
| Ozone Layer Depletion | Difference Between Evaporation and Transpiration |
Ques: Which of the following is not a part of the water cycle? (1 Mark)
- Cloud formation
- Rain
- Drinking by animals
- Sun
Ans: Option ‘c' is the correct answer. Animals do not drink as part of the water cycle.
Ques: Water circulation between the ocean and the land is referred to as (1 Mark)
- Water cycle
- Rain cycle
- Water management
- Water harvesting
Ans: Option ‘a' is the correct answer. The water cycle is the continuous flow of water from the earth to the atmosphere and back to the earth.
Ques: What are the different ways by which water vapour is put into the atmosphere? (3 Marks)
Ans: Water in oceans, lakes and ponds evaporates due to atmospheric heat. Factories and thermal power stations produce a lot of steam and put it into the atmosphere. Plants throw out water vapour by transpiration. Animals excrete water vapour through respiration and sweating. All this vapour accumulates in the atmosphere.
Ques: What is the importance of the water cycle? (2 Marks)
Ans: The water cycle is important for us because of the following reasons:
- Water cycle helps in regulating weather on earth.
- Water cycle makes water available in its various forms on the earth. The most important is the rainwater.
Ques: Is evaporation an endothermic or exothermic process? (1 Mark)
Ans: Evaporation is an endothermic process.
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