Class 8 Light Notes Light:- Light is a form of energy that produces sensation of vision in our eyes. Reflection of Light:- The phenomenon of bouncing back of a ray of light after striking on a highly polished (reflecting) surface is called reflection of light. Incident ray:- The light ray, which strikes any surface, is […]
Cell – Structure and Functions Notes Cell:- The cell is the basic structural and functional unit of our life. Cell was discovered by Robert Hooke in 1665. Different cells have different shapes like round, spherical, elongated, spindle (long and pointed at both ends) depending on their specific functions. Some cells have changing shape like amoeba and white blood […]
Coal and Petroleum Notes Natural Resources:– The resources, that are obtained from nature are called natural resources.Ex:- air, water, soil and minerals. Types of Natural resources:- Inexhaustible/ Renewable Natural Resources:- The resources which are present in unlimited quantity in nature and are not likely to be exhausted by human activities are called inexhaustible natural resources. […]
Synthetic Fibres and Plastics Notes Synthetic Fibres:- The synthetic fibres are man-made fibres which are made of small units of chemicals (monomers) joined together in the form of large chain. All the synthetic fibres are prepared using raw materials of petroleum origin, called petrochemicals. Polymer:- A single large unit made up of many small repeating […]
Microorganisms : Friend and Foe Notes Microorganisms/Microbes:- The living organisms which cannot be seen by the naked eyes but are only seen under the microscope are called microorganisms or microbes. The study of microorganisms is known as microbiology. Types of microorganisms:- Bacteria:- Staphylococcus, Lactobacillus. Fungi:- Bread mould, Yeast. Protozoans:- Paramoecium, Amoeba, Euglena. Algae:- Chlamydomonas, Spirogyra. […]
Crop Production and Management Notes Crop:- When plants of the same kind are grown and cultivated at one place on a large scale, it is called a crop. Types of crops:- Kharif Crops:- The crops which are sown in the rainy season are called kharif crops.Their time period is generally from June to September.Ex:- Paddy, […]