NCERT Solutions for Class 8 Science Chapter 18
Science tries to offer accurate and precise explanations of how the natural world works, what its constituents are, and how the world came to be the way it is now. Science’s knowledge is constantly being questioned and revised. Why isn’t any scientific notion ever “proven” once and for all? Science is always looking for new data that may uncover flaws in our existing understandings.
Our surroundings have changed dramatically over the last few decades, and pollution is one of the most important contributing factors. NCERT Class 8 Science Chapter 18 is Pollution of Air and Water. First, we will have a look at air and water pollution. Pollutants are chemicals that pollute water and air, according to Class 8 Science Chapter 18. Natural sources of pollution generally include smoke and dust from forest fires and volcanic eruptions. Artificial breakdown consists of the power plant and automotive emissions and firewood burning. The primary air pollutants include carbon dioxide, carbon monoxide, nitrogen oxides, sulphur dioxide and methane.
Extramarks’ website offers Class 8 Science Chapter 18 Solutions for students. These solutions help students grasp the root of the Chapter easily. Pollution of Air and Water Class 8 solutions help you learn the concepts through intensive answers to the NCERT questions and retain them. This is what makes Extramarks popular among students.
Extramarks can be a one-stop solution for all students’ problems. Apart from NCERT Solutions for Class 8 Science Chapter 12- Friction, NCERT Solutions for other subjects and chapters, Additional Questions, Sample Papers, Revision Notes, CBSE Previous year question papers, and a lot more can be found on the Extramarks website.
Key Topics Covered in NCERT Solutions for Class 8 Science Chapter 18
Making it convenient for the students and listing below the key topics that are covered in NCERT Solutions for Class 8 Science Chapter 18:
| Pollution |
| Air Pollution |
| Smog |
| Taj Mahal and the effects of Air pollution |
| Global Warming |
| Water Pollution |
Let us look at Extramarks’ in-depth information on each subtopic in NCERT Solutions for Class 8 Science Chapter 18- Pollution of Air and Water.
Pollution
According to NCERT Solutions for Class 8 Science Chapter 18, Pollution refers to unfavorable changes in the environment that harm plants, animals, and other biological and physical components of the environment.
- A pollutant is a chemical that creates pollution. Contaminants can exist as liquids, solids, or gases.
- When the concentration of a material exceeds the natural abundance, it is classified as a pollutant. Human actions or natural phenomena might cause this increase in concentration
- Pollution exists in all forms, viz. Air pollution, sound pollution, light pollution, water pollution, soil pollution, etc.
This chapter mainly focuses on two fundamental types of Pollution- Water and Air. Hence, let us take a look at the importance of both Water and Air:
Water
- Streams, rivers, lakes, and the season of the earth’s crust are primary water sources.
- It is essential for the survival of life on Earth.
- It is used for agriculture, drinking, washing, cleaning, and other human activities.
Air
- The presence of air in our life is unavoidable.
- The creatures’ survival depends on the availability of oxygen in the air.
- Their bodies use oxygen to make energy.
Air Pollution
Any physical, chemical or biological alteration in the air is air pollution. Air pollution occurs due to toxic gases, dust, and smoke which significantly impacts plants, animals, and humans.
Cause of Air Pollution
NCERT Solutions for Class 8 Science Chapter 18 briefs about the causes of Air Pollution:
- Sulphur dioxide is produced in significant quantities when fossil fuels are burned. In addition, air pollution is caused by carbon monoxide generated by the incomplete combustion of fossil fuels.
- Vehicles such as jeeps, trucks, cars , buses, and other automobiles generate gases that contaminate the environment. These are the primary contributors of greenhouse gases and cause sickness in people.
- Ammonia is one of the most dangerous gases produced by agricultural operations. Insecticides, fertilisers and pesticides pollute the atmosphere by emitting toxic substances.
- Carbon monoxide, hydrocarbons, organic molecules, and chemicals are primarily produced in factories and industries. These are discharged into the atmosphere, causing it to deteriorate.
- The minerals under the earth’s surface are retrieved using enormous equipment during the mining operation. The dust and chemicals emitted during the process contaminate the air and harm the employees’ and residents’ health.
- Toxic chemicals are released into the air through paints and household cleaning products which not only pollute the air but further make it difficult to breathe.
Effects of Air Pollution
- In humans, it causes allergies, illnesses, and sometimes even death.
- This causes birth abnormalities in newborns.
- Endangers animal health, plant and vegetation wellbeing.
Air Pollutants
Air pollutants can be defined as compounds present in high concentrations in the air which can be harmful to all the organisms or materials exposed to the atmosphere.
Solid particles, liquid droplets, and gases may have the presence of air pollutants, according to NCERT Solutions for Class 8 Science Chapter 18.
Examples are methane, chlorofluorocarbons, particulate matter, sulphur dioxide, nitrogen dioxide, carbon monoxide, lead, and other pollutants.
Carbon dioxide and Carbon monoxide
Carbon dioxide is produced via cement manufacture, deforestation, and the combustion of fuels such as gasoline, natural gas, oil, coal, and wood.
Incomplete combustion of carbon-containing materials, especially fuels, is a source of carbon monoxide (a harmful air pollutant).
Sulphur and Nitrogen
Primary air pollutants are nitrogen dioxide (NO2) and sulphur dioxide (SO2). Petroleum refineries and power stations that use fossil fuels such as coal are sources.
Effects:
- Respiratory issues, including irreversible lung damage.
- Acid rains.
- Photochemical haze, which makes it harder to breathe.
Particulate matter
Particulates are solid or liquid particles that stay suspended in air, water, or gas.
Dust, pollen, trash, soot, acid drops, and smoke are examples.
Construction, road dust, power plants, industry, deforestation, and agricultural operations are all causes.
Effects:
- Diseases of the lungs and heart
- Asthma
- Malformations during birth
The above section of NCERT Solutions for Class 8 Science Chapter 18 explains Air Pollution and its aspects in complete detail. For more information, refer to the Extramarks website. It is loaded with quality study material.
Smog
NCERT Solutions for Class 8 Science Chapter 18 explains that Smoke and fog combine to form Smog. There are two types of Smog- Classical and Photochemical Smog.
Classical Smog:
- This form of Smog arises in humid environments with high levels of sulfur oxides in the air.
- Smoke, fog, and mainly sulfur dioxide gas make up the combination.
Photochemical Smog:
- Smog of this sort is common in locations with a dry, sunny atmosphere and many automobiles.
- It is primarily generated by chemical reactions between sunlight and nitrogen oxides.
Effects of Smog:
- Asthma, wheezing, and cough are some examples of breathing problems.
- Damage to plant cells inhibits their development, resulting in a significant reduction in agriculture and forest destruction.
- Construction Materials, metals, and painted surfaces corrode due to photochemical pollution.
Taj Mahal and the effects of Air pollution
Before going into the case study of the Taj Mahal, NCERT Solutions for Class 8 Science Chapter 18 explains what CFCs or Chlorofluorocarbons are. CFCs are chemical compounds made up of fluorine, chlorine, and carbon. CFCs are majorly employed in aerosol sprays and as refrigerants in air conditioners, freezers, and cooling plants.
CFCs deplete the ozone layer, which shields the planet from the sun’s ultraviolet radiation. Humans can get ailments such as eye damage, skin cancer, and immune system suppression due to increasing UV radiation.
Effects of air pollution on Taj Mahal
The acids, Carbonic acid, Nitric acid, and Sulphuric acid are formed when carbon dioxide, sulfur dioxide, and nitrogen dioxide react with water vapor in the atmosphere.
Rain brings these acids down, making the environment acidic.
Involved reactions:
CO2(g) + 2H2O(I)= 2H2CO3(aq)
2SO2(g) + O2 + 2H2O(I)= 2H2SO4(aq)
4NO2 + O2(g) + 2H20(I)= 4HNO3(aq)
Effects:
- The monument’s marble is eroded by acid rain.
- In addition, the white marble is becoming dark because of pollution.
Global Warming
NCERT Solutions for Class 8 Science Chapter 18 lands on one of the essential topics of the chapter’ Global warming’.
Greenhouse Gases
The gases that cause the greenhouse effect are referred to as greenhouse gases. Water vapour, nitrous oxide, carbon dioxide, and methane are examples of such greenhouse gases.
Greenhouse effect:
- The majority of solar energy is absorbed by the atmosphere.
- The surface of the planet radiates heat back into space.
- A portion of it is trapped in the atmosphere by greenhouse gases.
- This effect keeps the earth’s surface at a comfortable temperature.
Global Warming
Global warming is defined as the phenomenon of rising in the average temperature of the earth’s atmosphere caused by an abundance of greenhouse gases.
Deforestation, factories, oil refineries, power plants, excessive burning of fossil fuels such as natural gas, oil, and coal, and so on are all contributing factors.
Effects of Global Warming:
- The earth’s temperature has increased on average throughout time.
- Natural disasters like floods, cyclones, earthquakes, and other natural disasters are becoming more severe.
- Due to global warming, the polar ice caps are melting and this has resulted in an increase in mean sea levels.
- Climate patterns have been changing all across the world.
What can we humans do to Reduce Air Pollution?
NCERT Solutions for Class 8 Science Chapter 18 suggests some ways in which Air Pollution can be reduced:
- Encourage the usage of compressed natural gas (CNG), which is a greener alternative to gasoline and diesel.
- Unleaded gasoline can be used because it does not emit dangerous gases into the environment.
- Maintain hygiene by properly disposing of waste to regions where it can be left, burnt, or safely disposed of.
- Taking public transportation or carpooling is cost-effective, relieves traffic congestion, and reduces emissions significantly.
Water Pollution
Extramarks NCERT Solutions for Class 8 Science Chapter 18 explains Water Pollution in the following section. The contamination of water bodies with toxic waste is known as water pollution.
Causes:
- Industries
- Agriculture
- Urbanization
- Religious and social customs
Water Pollutants
Water pollutants are compounds that contaminate the water. Detergents, hospital chemicals, insecticides and herbicides, to name a few.
Effects of water pollution on the holy river Ganga
- Garbage, untreated sewage, corpses, and various other dangerous substances are dumped straight into the river by the people of towns and cities through which the river passes.
- Pollution in the Ganga is suffocating aquatic life and stunting plant development.
- The Ganga is one of the world’s ten most threatened rivers.
Potable and Raw Water
Potable water is water that is good for drinking. All pollutants and dangerous microorganisms are removed from the drinking water.
Raw water is water that is not potable or appropriate for consumption.
Ways to convert Raw to Potable Water.
Extramarks NCERT Solutions for Class 8 Science Chapter 18 states that the following are the ways to convert Raw water to Potable water:
Boiling Water:
- All germs are killed by boiling the water.
- It protects us from infections spread by water.
Filtering Water:
- Removing suspended solid materials from a liquid is known as filtration.
- To some extent, filtration may remove all bacteria and pollutants from water.
Chlorination:
- The water is chlorinated by adding chlorine pills or bleaching powder.
- In tap water, this procedure destroys some bacteria and other germs.
NCERT Solutions for Class 8 Science Chapter 18 Exercise and Solutions
Studying the NCERT Solutions for any chapter is the most innovative way to grasp all of the concepts in that Chapter. Extramarks deliver NCERT Solutions for each Chapter as a bonus. Subject experts create these Solutions to meet all of the demands of the students. Click on the below links to view NCERT Solutions for Class 8 Science Chapter 18:
Class 8 Science Chapter 18: Very Short Answer Type Questions
Class 8 Science Chapter 18: Short Answer Type Questions
Class 8 Science Chapter 18: Long Answer Type Questions
Students may access NCERT Solutions for Class 8 Science Chapter 18 and other chapters by clicking here. In addition, students can also explore NCERT Solutions for other classes below.
By getting access to NCERT Solutions for Class 8 Science Chapter 18- Pollution of Air and Water, students can easily understand and retain all the answers of the NCERT questions given at the end of the Chapter
NCERT Solutions Class 8 Science Chapter-wise List
Key Features of NCERT Solutions for Class 8 Science Chapter 18
To excel in the forthcoming examination, students are advised to go through the NCERT Solutions of each Chapter. So why should you choose Extramarks? Here’s why:
- They consist of stepwise and detailed answers including various concepts covered in the Chapter.
- Based on the NCERT standards, Extramarks has compiled the most relevant material on this topic.
- After studying these Solutions, students are instilled with confidence.