Class 8th Science NCERT: Crop, Microorganisms, Fibres, Coal, Petroleum

Class 8th Science NCERT All Chapters

Chapter 1: Crop Production and Management

Crop production and management is an essential aspect of agriculture, focusing on the processes involved in growing crops, maintaining their health, and ensuring a bountiful harvest. Some key topics covered in this chapter include:

• Planting: This involves preparing the soil, choosing the right season, and planting the seeds. The correct spacing between plants and rows is also crucial for proper growth.

• Watering: Crop irrigation is a crucial aspect of crop production, ensuring that plants receive the appropriate amount of water. Techniques such as drip irrigation are discussed.

• Weed Management: This involves controlling the growth of unwanted plants, which can compete with crops for nutrients and water.

• Pests and Diseases: Management of pests and diseases in crops is essential to prevent crop failure. Techniques such as crop rotation and using natural enemies of pests are discussed.

• Harvesting: This involves the process of collecting the matured crop from the fields.

Chapter 2: Microorganisms: Friend and Foe

Microorganisms play a significant role in various processes, both beneficial and detrimental. Some key topics covered in this chapter include:

• Bacteria: These single-celled microorganisms are essential for decomposition and nutrient cycling. Some bacteria are pathogens that can cause diseases in humans and animals.

• Fungi: These are unicellular or multicellular organisms that play a crucial role in decomposition and nutrient cycling. Some fungi cause diseases in plants.

• Viruses: These are obligate intracellular parasites that replicate within other organisms. Some viruses cause diseases in plants, animals, and humans.

• Protists: These are unicellular eukaryotes that play various roles in the ecosystem. Some protists are parasitic, causing diseases in humans and animals.

Chapter 3: Synthetic Fibres and Plastics

Synthetic fibers and plastics are artificial materials made from natural resources or synthetic chemical products. Some key topics covered in this chapter include:

• Natural Fibers: These are fibers obtained from natural sources such as plants, animals, and minerals. Examples include cotton, silk, wool, and jute.

• Synthetic Fibers: These are fibers made from synthetic materials such as polyester, nylon, and acrylic. They are stronger, lighter, and more durable than natural fibers.

• Plastics: These are polymers that are widely used in various industries. They are derived from petroleum and natural gas.

• Properties and Use of Synthetic Fibers and Plastics: These materials have unique properties that make them suitable for various applications. Some common uses include packaging, construction, and clothing.

Chapter 4: Coal and Petroleum

Coal and petroleum are important natural resources that play a significant role in the global economy. Some key topics covered in this chapter include:

• Coal: This is a sedimentary rock formed from the accumulation of organic matter over millions of years. It is a major source of energy and is used in power generation and various industries.

• Petroleum: This is a mixture of hydrocarbons that is found in underground reservoirs. It is a major source of energy and is used in transportation, heating, and manufacturing.

• Formation of Coal and Petroleum: These resources are formed from the remains of ancient plants and animals that have been subjected to high pressure and temperature over millions of years.

• Extraction of Coal and Petroleum: These resources are extracted through various methods such as mining and drilling.

• Environmental Impact of Coal and Petroleum: The extraction and use of these resources have significant environmental impacts, including air pollution and greenhouse gas emissions.