Page 1 - 2. Lesson notes- Water; water pollution

SAI International School
Subject- Biology
Chapter- Natural Resources
Subtopic- Water; water pollution
Module- 32
Lesson Notes

Sources of Water
There are various sources of water. About 97% of the water on the Earth’s surface is covered

with water. The three main sources of water are:

• Rainwater.
• Groundwater – This includes water bodies like Wells and Springs.

• Surface water – This includes different water bodies like Sea, Oceans, Reservoirs,

Rivers, Streams, Ponds, Lakes, and Tanks.

Importance of Water

We all need water for different daily activities including:

• Domestic Purposes include bathing, cleaning, cooking, drinking, and washing.
• Agricultural applications include irrigation, farming, gardening, and frost control.

• Other Industrial Applications.

Apart from this, we drink water to:

• Stay hydrated

• Lubricate Joints

• Regulate the body’s temperature. Required for all cellular activities.
• Transport nutrients and other waste in the body.

• Balance the loss of water from the digestive tract and body tissues.

• Terrestrial life forms need fresh water as they cannot get rid of the high amount of
dissolved salt found in their body like marine animals.