• Home
  • Courses
  • Online Test
  • Contact
    Have any question?
    +91-8287971571
    contact@dronstudy.com
    Login
    DronStudy
    • Home
    • Courses
    • Online Test
    • Contact

      Class 8 Science

      • Home
      • All courses
      • Class 08
      • Class 8 Science
      CoursesClass 08ScienceClass 8 Science
      • Cell- Structure and Function
        6
        • Lecture1.1
          Introduction, Discovery, Cell Theory, Cell Variation, Cell Structure-Cell Wall 31 min
        • Lecture1.2
          Cell Structure and Function -Cell Membrane, Cytoplasm, Nucleus 31 min
        • Lecture1.3
          Cell Structure and Function -Ribosomes, ER, Golgi Bodies, Lysosomes, Mitochondria 38 min
        • Lecture1.4
          Cell Structure and Function – Plastids, Vacuole, Types of Cell 20 min
        • Lecture1.5
          Chapter Notes – Cell
        • Lecture1.6
          NCERT Solutions – Cell
      • Light
        6
        • Lecture2.1
          Plane Mirror, Laws of Reflection 01 hour
        • Lecture2.2
          Multiple Reflection,Dispersion 41 min
        • Lecture2.3
          Human Eye 59 min
        • Lecture2.4
          Light Introduction 10 min
        • Lecture2.5
          Chapter Notes – Light
        • Lecture2.6
          NCERT Solutions -Light
      • Synthetic Fibers an Plastics
        3
        • Lecture3.1
          Introduction, Natural Fiber, Synthetic Fibers, Plastics and its Uses, Biodegradable & non-biodegradable wastes, Effect of Plastics on Environment 45 min
        • Lecture3.2
          Chapter Notes – Synthetic Fibers an Plastics
        • Lecture3.3
          NCERT Solutions – Synthetic Fibers an Plastics
      • Coal and Petroleum
        4
        • Lecture4.1
          Introduction, Natural Resources, Fuel-Coal 16 min
        • Lecture4.2
          Fuel-Petroleum, Natural Gas 18 min
        • Lecture4.3
          Chapter Notes – Coal and Petroleum
        • Lecture4.4
          NCERT Solutions – Coal and Petroleum
      • Stars and The Solar System
        6
        • Lecture5.1
          Celestial Objects or Heavenly Bodies 27 min
        • Lecture5.2
          Stars, Constellations 23 min
        • Lecture5.3
          Solar System 35 min
        • Lecture5.4
          Asteroids, Comets and Satellites 31 min
        • Lecture5.5
          Chapter Notes – Stars and The Solar System
        • Lecture5.6
          NCERT Solutions – Stars and The Solar System
      • Pollution of Air and Water
        5
        • Lecture6.1
          Air Pollution 21 min
        • Lecture6.2
          Greenhouse 50 min
        • Lecture6.3
          Water Pollution 30 min
        • Lecture6.4
          Chapter Notes – Pollution of Air and Water
        • Lecture6.5
          NCERT Solutions – Pollution of Air and Water
      • Force and Pressure
        4
        • Lecture7.1
          Force 12 min
        • Lecture7.2
          Pressure 45 min
        • Lecture7.3
          Chapter Notes – Force and Pressure
        • Lecture7.4
          NCERT Solutions – Force and Pressure
      • Friction
        3
        • Lecture8.1
          Introduction 25 min
        • Lecture8.2
          Chapter Notes – Friction
        • Lecture8.3
          NCERT Solutions – Friction
      • Sound
        4
        • Lecture9.1
          Introduction, Production & Propagation and Medium 41 min
        • Lecture9.2
          Reflection Of Sound 16 min
        • Lecture9.3
          Chapter Notes – Sound
        • Lecture9.4
          NCERT Solutions – Sound
      • Materials: Metals and Non-Metals
        4
        • Lecture10.1
          Physical Properties of metals and non-metals-1 25 min
        • Lecture10.2
          Physical Properties of metals and non-metals-2 06 min
        • Lecture10.3
          Chapter Notes – Materials: Metals and Non-Metals
        • Lecture10.4
          NCERT Solutions – Materials: Metals and Non-Metals

        NCERT Solutions – Pollution of Air and Water

        Q.1 What are the different ways in which water gets contaminated?
        Sol. The different ways in which water gets contaminated are as follows:
        (i) Many industries discharge harmful chemicals into rivers and streams. Examples are oil refineries, paper factories, textile and sugar mills, etc.
        (ii) The pesticides and weedicides used for the protection of crops get dissolved in water and are washed into water bodies from the fields.
        (iii) Many times untreated sewage is thrown directly into rivers.
        (iv) Faecal matters of mammals get added into water bodies.

        Q.2 At an individual level, how can you help reduce air pollution?
        Sol. At an individual level, one can do following things to reduce air pollution:
        (i) One can use vehicles consuming fuels like CNG and unleaded petrol, rather than those using fuels like diesel, petrol, etc.
        (ii) One can avoid unnecessary usage of vehicles. And try using public transport more.
        (iii) One can avoid using crackers.
        (iv) One can generate awareness about air pollution among friends and neighbours.
        (v) One can switch over to alternative fuels instead of the fossil fuels for energy requirements. These could be solar energy, hydropower and wind energy.
        (vi) One can plant trees and nurture those trees already present in the neighbourhood.
        (vii) Dry leaves can be burnt in a compost pit rather than burning in open.

        Q.3 Clear, transparent water is always fit for drinking. Comment.
        Sol. Clear, transparent water is not always fit for drinking. This is because the water which looks clean might contain disease-carrying microorganisms and dissolved impurities in it. These microorganisms and impurities could be harmful to us. Hence, it is essential to purify water before drinking.

        Q.4 You are a member of the municipal body of your town.
        Make a list of measures that would help your town to ensure the supply of clean water to all its residents.
        Sol. Following is a list of measures that would help a town to ensure the supply of clean water to all its residents:
        (i) Implementation of strict laws for industrial units so that the polluted water is not disposed off directly into rivers and lakes. Because it is same water we receive at our home.
        (ii) Treatment of water must be done to make it free from harmful germs, chemicals and impurities.
        (iii) The water supply pipes must be properly maintained to avoid any corrosion, breakage and leakage.
        (vi) Campaigns and awareness programmes should be organized to keep water resources clean and educate people to save water.

        Q.5 Explain the differences between pure air and polluted air.
        Sol. Pure air: It is a mixture of gases which contains about 78% nitrogen, 21% oxygen and rest consists of carbon dioxide, argon, methane, ozone and water vapour. Such air is good for living being.
        Polluted air: It is the air which is contaminated by unwanted substances which have a harmful effect on both the living and the non-living.

        Q.6 Explain circumstances leading to acid rain. How does acid rain affect us?
        Sol. Chemicals like sulphur dioxide and nitrogen dioxide are released into the air. These pollutants reacts with the water vapour present in the air and forms sulphuric and nitric acid. When it rains, these acids are present in it. Such kind of rain is called Acid Rain.
        Following is list which shows how acid rain affect us:
        (i) It can cause skin irritation.
        (ii) It removes nutrients like calcium from the soil.
        (iii) It causes corrosion to bridges, building and other metallic objects.
        (iv) It can destroy plants and aquatic life.

        Q.7 Which of the following is not a greenhouse gas?
        (a) Carbon dioxide
        (b) Sulphur dioxide
        (c) Methane
        (d) Nitrogen
        Sol. (d) Nitrogen

        Q.8 Describe the ‘Green House Effect’ in your own words.
        Sol. ‘Green House Effect’ is the trapping of radiations inside the earth’s atmosphere. Along with other gases, CO2 also gets trapped in the atmosphere which is mainly responsible for Greenhouse Effect. Because of human activities the amount of CO2 level has increased in the atmosphere which traps heat and does not allow heat to escape into space. As a result, the average temperature of the earth’s atmosphere is gradually increasing. This is called global warming.

        Q.9 Prepare a brief speech on global warming that you have to make in your class.
        Sol. The continuous increase in the temperature of the earth is called Global Warming. Various gases like carbon dioxide, nitrous oxide, methane, etc. lead to this effect. But, the main contributor of global warming is Carbon dioxide. It traps the heat and does not allow it to escape into space. As a result, the average temperature of Earth is increasing. There are many effects of global warming like it can cause sea levels to rise dramatically. Moreover, it could result in wide ranging effects on rainfall patterns, agriculture, forests, plants and animals. Hence, we need to take steps to minimize it. It cannot be solved by the effort of only one country, it needs global effort of all countries to reduces its effects and completely eliminate it.

        Q.10 Describe the threat to the beauty of the Taj Mahal.
        Sol. Chemicals like sulphur dioxide and nitrogen dioxide are released into the air. The pollutants reacts with the water vapour present in the air and forms sulphuric and nitric acid. When it rains, these acids are also present. Such kind of rain is called Acid Rain. Acid rain can be harmful for living beings and also for non-living things. Acid rain corrodes the outer surface of buildings. This has caused the Taj Mahal becoming pale. The Acid rain has corroded the marble of this monument. And this phenomenon is called “Marble cancer”. In fact, suspended particulate matter, such as the soot particles emitted by Mathura oil refinery, has contributed towards yellowing of the marble.

        Q.11 Why does the increased level of nutrients in the water affect the survival of aquatic organisms?
        Sol. The pesticides and weedicides used for the protection of crops get dissolved in water and are washed into water bodies from the fields. These acts as nutrients for algae to flourish. Once these algae die, they serve as food for decomposers like bacteria. In this process a lot of oxygen in these ponds gets used up. This results in a decrease in the oxygen level, which kills aquatic organisms.

        Prev Chapter Notes – Pollution of Air and Water
        Next Force

          3 Comments

        1. MD HARISH
          November 14, 2021
          Reply

          Excellent sir thank you so much sir

          • MD HARISH
            November 14, 2021
            Reply

            Excellent sir

        2. MD HARISH
          November 14, 2021
          Reply

          Excellent sir

        Leave A Reply Cancel reply

        Your email address will not be published. Required fields are marked *

        All Courses

        • Backend
        • Chemistry
        • Chemistry
        • Chemistry
        • Class 08
          • Maths
          • Science
        • Class 09
          • Maths
          • Science
          • Social Studies
        • Class 10
          • Maths
          • Science
          • Social Studies
        • Class 11
          • Chemistry
          • English
          • Maths
          • Physics
        • Class 12
          • Chemistry
          • English
          • Maths
          • Physics
        • CSS
        • English
        • English
        • Frontend
        • General
        • IT & Software
        • JEE Foundation (Class 9 & 10)
          • Chemistry
          • Physics
        • Maths
        • Maths
        • Maths
        • Maths
        • Maths
        • Photography
        • Physics
        • Physics
        • Physics
        • Programming Language
        • Science
        • Science
        • Science
        • Social Studies
        • Social Studies
        • Technology

        Latest Courses

        Class 8 Science

        Class 8 Science

        ₹8,000.00
        Class 8 Maths

        Class 8 Maths

        ₹8,000.00
        Class 9 Science

        Class 9 Science

        ₹10,000.00

        Contact Us

        +91-8287971571

        contact@dronstudy.com

        Company

        • About Us
        • Contact
        • Privacy Policy

        Links

        • Courses
        • Test Series

        Copyright © 2021 DronStudy Pvt. Ltd.

        Login with your site account

        Lost your password?

        Modal title

        Message modal