Class 5 Evs - ICSE-SCIENCE
Air and Water - Composition, Pollution, Purification
This chapter explores two of our most vital natural resources: air and water. Class 5 ICSE Science students will learn about the gaseous composition of air, the layers of the atmosphere, and the importance of oxygen and carbon dioxide in nature. The chapter details major causes of air and water pollution, their harmful effects on human health and the environment, and preventive measures. Additionally, students will study natural and man-made methods of water purification, including filtration, sedimentation, chlorination, and boiling, making this a high-scoring topic essential for board exam success.
Start Learning FreeKey Concepts
Composition of Air
Air is a mixture of gases containing about 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases like argon, carbon dioxide, and water vapor.
Air Pollution
The contamination of air by harmful gases, smoke, and dust particles released from vehicles, factories, and burning garbage, which causes respiratory diseases.
Water Pollution
The contamination of water bodies like rivers, lakes, and oceans due to industrial waste, sewage dumping, and the use of chemical fertilizers in farming.
Sedimentation and Decantation
Processes used to purify water where heavy insoluble impurities settle down at the bottom (sedimentation), and the clean water is gently poured out (decantation).
Chlorination
A water purification method in which small amounts of chlorine are added to drinking water to kill harmful germs and bacteria.
Important Formulas
Board Exam Info
In ICSE Science exams, this chapter typically carries around 6 to 8 marks. Questions frequently include differentiating between air and water pollution, naming the gases in the air with their percentages, explaining methods of water purification, and suggesting ways to reduce pollution.
Frequently Asked Questions
Why is nitrogen important in the air if we breathe oxygen?
Nitrogen dilutes oxygen and prevents things from burning too fast or catching fire easily, and plants need it to grow.
What is the difference between sedimentation and filtration?
Sedimentation allows heavy dirt to settle at the bottom of a container on its own, whereas filtration passes water through a filter paper or net to trap smaller solid particles.
Is boiling enough to make muddy water safe to drink?
No, boiling kills germs and bacteria, but it does not remove dirt or mud. Water must first be filtered to remove solid impurities and then boiled.
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