Water: A Precious Resource class 7 Worksheet and quick notes for revision
Water a precious resource. Download Water: A Precious Resource class 7 Worksheet based on the latest CBSE syllabus including MCQ questions, Water a precious resource notes, long questions, and more.
Water: A Precious Resource notes
22 March is celebrated as world water day.
water circulates through the water cycle it can be found in all three forms, i.e., solid, liquid, and gas—at any given time somewhere on the earth.
If we dig a hole in the ground near a water body we may find that the soil is moist. The moisture in the soil indicates the presence of water underground. If we dig deeper and deeper, we would reach a level where all the space between particles of soil and gaps between rocks are filled with water. The upper level of this layer is called the water table. The process of seeping water into the ground is called infiltration
The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration. At places, the groundwater is stored between layers of hard rock below the water table. This is known as an aquifer.
Life on the Earth cannot exist without water. More than 70% of the human body is composed of water. We require 2 to 3 liters of water every day.
Lithosphere: The solid parts of the earth's crust, called the lithosphere
Hydrosphere: The water bodies, such as seas, rivers and lakes on the earth, which constitute hydrosphere
Atmosphere: The gases surrounding the earth, known as the atmosphere.
Renewable and Non-renewable Resources: Renewable resources are those that will either never run out or those which we can use again and again eg oxygen
whereas Non-renewable resources are those which cannot be used again and again, after some time it will get vanished eg petrol, water.
Melting point: When ice is heated, it melts to form water at 0oC. This is called the melting point of ice. However, if the water is cooled, it changes to the ice at the same temperature i.e at 0 0C. The freezing point of water is therefore 00C.
Evaporation: Water changes to water vapour at all temperature, this is known as evaporation.