Notes

Reflection * Based on the nature of the reflecting surface, reflection can be regular and irregular. * Images can be real images that can be caught on a screen, or virtual images that cannot be caught on a screen. Images formed in a plane mirror are virtual. According to the laws of reflection:   *  ... Read more

Heredity and Variations * The process of passing of the traits from parents to offspring is called Heredity. * Offspring are never an exact copy of their parents. They show minor differences, which are called Variations. * Mendel was the pioneer among Geneticists who found the inheritance of characters from parents to offspring. * A ... Read more

Reproduction and its Significance * Reproduction is the process by which an organism gives birth to a new individual. * DNA variation is useful for the survival of a species, during drastic changes in their environment. * DNA variations are passed to the subsequent generations when they reproduce. Reproduction in Unicellular and Multicellular Organisms * ... Read more

Nervous System * The nervous system is made up of the brain, spinal cord and a huge network of nerves that thread through our body. * The nervous system is responsible for sending, receiving and processing nerve impulses. * Neurons are the fundamental unit of the nervous system. The axons of the nervous bundle together ... Read more

Photosynthesis * The process that helps in carrying out metabolic functions of living organisms are called life processes. * The process of obtaining energy from food is called nutrition. * Preparation of organic compounds from inorganic substances is called autotrophic nutrition. * Heterotrophs depend on autotrophs for nutrition. * The process of fixation of atmospheric ... Read more

History of Periodic Table * Dobereiner’s law of triads: In a triad, the atomic mass of the middle element is equal to the arithmetic mean of the atomic masses of the other two. * Newlands law of octaves: When elements are arranged in increasing order of their atomic weights, the properties of the eighth element ... Read more

Forms of Carbon * Carbon is the sixth most abundant element in the universe. * In the free state, carbon occurs as diamond, graphite, fullerene and coal. * In the combined state, carbon can be in the form of carbon dioxide, carbon monoxide, petroleum, vegetable oils, lime stone, magnetite, dolomite and calamine. * Allotropy is ... Read more

Metals and Non-metals * Metals are elements that have a tendency to lose electrons and form positively charged ions or cations. * Elements that have a tendency to accept electrons to form negatively charged ions or anions are called non-metals. * Metals are placed on the extreme left in the periodic table, while non-metals are ... Read more