Class 8 Science Revision Notes
Crop Production and Management Notes
Crop Production and Management — Notes A crop is the same kind of plant grown on a large scale. Crops are seasonal: kharif (rainy season) and rabi (winter). Basic agricultural pra…
Microorganisms: Friend and Foe Notes
Microorganisms: Friend and Foe — Notes Microorganisms are tiny organisms seen only under a microscope. Major groups Bacteria, fungi, protozoa, algae and viruses (viruses reproduce…
Coal and Petroleum Notes
Coal and Petroleum — Notes Types of resources Exhaustible (non renewable): limited and will finish (coal, petroleum, natural gas — the fossil fuels ). Inexhaustible (renewable): p…
Combustion and Flame Notes
Combustion and Flame — Notes Combustion is a chemical process in which a substance burns in the presence of oxygen, giving heat and usually light. Conditions for combustion A comb…
Conservation of Plants and Animals Notes
Conservation of Plants and Animals — Notes Why conserve? Deforestation (clearing forests) reduces rainfall, lowers soil fertility, causes floods and threatens wildlife, reducing b…
Reproduction in Animals Notes
Reproduction in Animals — Notes Reproduction is the production of new individuals of the same kind. Modes of reproduction Sexual reproduction: needs two parents; male and female g…
Reaching the Age of Adolescence Notes
Reaching the Age of Adolescence — Notes Adolescence is the period of growth from about 11 to 19 years, when the body becomes capable of reproduction. The phase of these changes is…
Force and Pressure Notes
Force and Pressure — Notes Force A force is a push or a pull. It can change the state of motion , the speed , the direction or the shape of an object. Contact forces: muscular for…
Friction Notes
Friction — Notes Friction is the force that opposes the relative motion between two surfaces in contact. Cause and types Friction is caused by the irregularities of surfaces. It a…
Sound Notes
Sound — Notes Sound is produced by vibrating objects and needs a medium to travel; it cannot travel through a vacuum. How we hear Vibrations travel through air to the eardrum , wh…
Chemical Effects of Electric Current Notes
Chemical Effects of Electric Current — Notes Conduction in liquids Some liquids conduct electricity and some do not. Good conductors: solutions of acids, bases and salts (and most…
Some Natural Phenomena Notes
Some Natural Phenomena — Notes This chapter explains lightning and earthquakes. Charging by rubbing Rubbing certain objects makes them charged . There are two kinds of charge — po…