The Human Eye and the Colourful World 1. The Human Eye The human eye is a natural optical instrument used for vision. It functions similarly to a camera with a lens and screen system. Retina: Light-sensitive screen inside the eye where the image is formed, containing rods and cones. Cornea: Thin membrane covering the eyeball, … Read more
Light: Reflection and Refraction 1. Ray of Light A line drawn in the direction of propagation of light is called a ray of light. 2. Beam of Light A group of rays of light emitted by a source of light is called a beam of light. A light beam is of three types: Parallel beam: … Read more
Heredity and Evolution 1. Heredity The transmission of characters from parent to their offspring is known as heredity. The study of heredity and variations is known as genetics. Clones are organisms that are carbon copies of one another. Variation in sexually reproducing organisms is caused due to factors like environment, crossing over, recombination of genes, … Read more
Diversity in Living Organisms 1. Reproduction The production of new organisms from existing organisms of the same species is known as reproduction. 2. Asexual Reproduction Modes of asexual reproduction used are: Binary fission Multiple fission Budding Spore formation Regeneration Vegetative propagation Tissue culture Fragmentation 3. Sexual Reproduction In sexual reproduction, a male gamete (germ cell) … Read more
Control and Coordination Animals- Nervous System: Nervous system is the organ system present in the animals to control and coordinate different activities of the body. Nervous system comprises of the brain, the spinal cord, and a huge network of nerves that are spread throughout the body. The nervous system is responsible for sending, receiving and … Read more
Chapter 6: Life Processes Life Processes The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc. Criteria of Life Growth Movement Nutrition The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body. … Read more
Periodic Classification of Elements 1. Introduction to Classification Classification is an essential concept in science that involves identifying and grouping similar elements based on their properties. The periodic classification of elements has evolved over time as new elements were discovered and scientific understanding improved. 2. Lavoisier’s Classification Lavoisier, a French chemist, classified elements into two … Read more
Carbon and its Compounds 1. Bonding in Carbon Carbon is a unique element in the periodic table due to its ability to form covalent bonds. It has four valence electrons, allowing it to share electrons with other elements to achieve stability. Formation of Covalent Bond: Covalent bonding involves the sharing of electrons between atoms. These … Read more
Chapter 3 – Metals and Non-Metals Gist of the Lesson Elements are classified broadly into two categories on the basis of properties: Metals: Iron, Zinc, Copper, Aluminium etc. Non-Metals: Chlorine, Nitrogen, Hydrogen, Oxygen, Sulphur etc. Apart from metals and non-metals, some elements show properties of both metals and non-metals, e.g., Silicon, Arsenic, Germanium. They are … Read more
Properties of Acids: Produce hydrogen ions [H+] in H2O. Sour taste. Turn blue litmus red. Act as electrolytes in Solution. Neutralize solutions carrying hydroxide ions. React with several metals releasing Hydrogen gas. React with carbonates releasing CO2 (g) Destroy body tissues. Corrode metal surface quickly. On the basis of origin, acids are classified as: a. … Read more