Class 8 – NCERT Science Complete Notes
Original, exam■oriented notes written in simple English. Useful for revision, understanding
concepts, and exams.
, Crop Production and Management
Agricultural practices include preparation of soil, sowing, adding manure and fertilizers, irrigation,
protection from weeds, harvesting, and storage.
Ploughing loosens soil, improves aeration, and helps roots grow deeper.
Manure improves soil fertility naturally, while fertilizers provide specific nutrients quickly.
Irrigation methods include traditional methods and modern methods like drip and sprinkler
systems.
Weeds compete with crops for nutrients, water, and sunlight and are removed manually or using
weedicides.
Microorganisms: Friend and Foe
Microorganisms include bacteria, fungi, protozoa, algae, and viruses.
Useful microorganisms help in making curd, bread, medicines, and decomposing waste.
Harmful microorganisms cause diseases in humans, animals, and plants.
Vaccination helps prevent diseases by developing immunity.
Food preservation methods include refrigeration, salting, sugaring, and use of preservatives.
Synthetic Fibres and Plastics
Synthetic fibres are man-made fibres such as nylon, polyester, and acrylic.
They are strong, lightweight, and durable but not biodegradable.
Plastics are classified as thermoplastics and thermosetting plastics.
Plastics are widely used but cause environmental pollution.
Reduce, Reuse, and Recycle principles help control plastic pollution.
Materials: Metals and Non-Metals
Metals are generally hard, shiny, and good conductors of heat and electricity.
Non-metals are dull, soft, and poor conductors.
Metals like iron rust when exposed to air and moisture.
Some metals are extracted from ores using heating and chemical processes.
Uses of metals and non-metals depend on their properties.
Coal and Petroleum
Original, exam■oriented notes written in simple English. Useful for revision, understanding
concepts, and exams.
, Crop Production and Management
Agricultural practices include preparation of soil, sowing, adding manure and fertilizers, irrigation,
protection from weeds, harvesting, and storage.
Ploughing loosens soil, improves aeration, and helps roots grow deeper.
Manure improves soil fertility naturally, while fertilizers provide specific nutrients quickly.
Irrigation methods include traditional methods and modern methods like drip and sprinkler
systems.
Weeds compete with crops for nutrients, water, and sunlight and are removed manually or using
weedicides.
Microorganisms: Friend and Foe
Microorganisms include bacteria, fungi, protozoa, algae, and viruses.
Useful microorganisms help in making curd, bread, medicines, and decomposing waste.
Harmful microorganisms cause diseases in humans, animals, and plants.
Vaccination helps prevent diseases by developing immunity.
Food preservation methods include refrigeration, salting, sugaring, and use of preservatives.
Synthetic Fibres and Plastics
Synthetic fibres are man-made fibres such as nylon, polyester, and acrylic.
They are strong, lightweight, and durable but not biodegradable.
Plastics are classified as thermoplastics and thermosetting plastics.
Plastics are widely used but cause environmental pollution.
Reduce, Reuse, and Recycle principles help control plastic pollution.
Materials: Metals and Non-Metals
Metals are generally hard, shiny, and good conductors of heat and electricity.
Non-metals are dull, soft, and poor conductors.
Metals like iron rust when exposed to air and moisture.
Some metals are extracted from ores using heating and chemical processes.
Uses of metals and non-metals depend on their properties.
Coal and Petroleum
