CBSE NCERT Solutions for Class 8 Science Chapter 18

The importance of studying NCERT books is to achieve success in exams. Students are advised to stick to the NCERT books to make full use of their limited time and score optimum in exam.

CBSE NCERT Solutions for Class 8 Science Chapter 18:

Question-1:

At an individual level, how can you help reduce air pollution?

Solution:

An individual can reduce air pollution by:
→ Avoiding the use of cars as much as possible and by using public transport whenever possible.
→ By not using vehicles for short distances.
→ By using clean fuels such as LPG and CNG instead of diesel and petrol.
→ Always disposing the garbage properly and not burning it.
→ Controlling the emissions from vehicles and household chimneys.

Question-2:

Explain circumstances leading to acid rain. How does acid rain affect us?

Solution:

When harmful gases like sulphur dioxide and nitrogen dioxide, react with moisture present in air, they form nitric acid and sulphuric acid. These acids when drop
down on earth along with rain, is called acid rain. Effects of acid rain:
→ Acid rains damage crops, decrease fertility of soil and affect aquatic life.
→ Acid rains corrode buildings and structures

Question-3:

Which of the following is not a greenhouse gas?
(a) Carbon dioxide
(b) Sulphur dioxide
(c) Methane
(d) Nitrogen

Solution:

(d) Nitrogen

Question-4:

Prepare a brief speech on global warming. You have to deliver the speech in
your class.

Solution:

Global warming is one of the greatest challenges that our planet is facing. It is the unequivocal and continuing rise in the average temperature of the Earth’s climate system. It occurs as a result of an increased concentration of greenhouse gases in the atmosphere. These gases trap solar radiations released back by the Earth. This helps in keeping our planet warm and thus, helps in human survival. However, an increase in the amount of greenhouse gases can lead to an increase in the Earth's temperature leading to global warming.