NCERT Class 10 Science Core Vocabulary

Comprehensive vocabulary flashcards generated from the Class 10 NCERT Science syllabus, defining key terms, chemical reactions, physical concepts, biological processes, and ecological terms.

Chemical Reaction

A process in which the chemical nature and identity of the initial substance change, resulting in the formation of new chemical substances with distinct properties.

Combination Reaction

A chemical reaction in which two or more reactants combine to form a single product.

Decomposition Reaction

A chemical reaction in which a single reactant breaks down to yield two or more simpler products.

Displacement Reaction

A chemical reaction in which a more reactive element displaces a less reactive element from its compound solution.

Double Displacement Reaction

A reaction in which there is an exchange of ions between the reactants to form new compounds.

Precipitation Reaction

Any chemical reaction that produces an insoluble solid product called a precipitate.

Oxidation

The gain of oxygen or the loss of hydrogen by a substance during a chemical reaction.

Reduction

The loss of oxygen or the gain of hydrogen by a substance during a chemical reaction.

Exothermic Reaction

A reaction in which heat energy is released along with the formation of products.

Endothermic Reaction

A reaction in which heat or other forms of energy are absorbed.

Corrosion

The gradual degradation of a metal when it is attacked by substances in its surroundings such as moisture, air, or acids.

Rancidity

The oxidation of fats and oils in food when exposed to air, leading to an unpleasant smell and taste.

Olfactory Indicator

A substance whose odour changes depending on whether it is placed in an acidic or basic medium.

Neutralisation Reaction

The chemical reaction between an acid and a base to produce salt and water.

pH Scale

A scale used for measuring hydrogen ion concentration in a solution, ranging from $0$ (highly acidic) to $14$ (highly alkaline).

Water of Crystallisation

The fixed number of water molecules present in one formula unit of a crystalline salt.

Plaster of Paris

Calcium sulphate hemihydrate ($CaSO_4 \times \frac{1}{2}H_2O$) produced by heating gypsum at $373\,K$.

Malleability

The physical property of a metal that allows it to be beaten into thin sheets without breaking.

Ductility

The physical property of a metal that enables it to be drawn into long, thin wires.

Anodising

An electrochemical process that forms a thick, protective oxide layer on aluminium to prevent further corrosion.

Amphoteric Oxide

A metal oxide that exhibits both acidic and basic properties, reacting with both acids and bases to form salt and water.

Reactivity Series

A series of metals arranged in the order of their decreasing chemical reactivity.

Roasting

The process of heating a sulphide ore strongly in the presence of excess air to convert it into a metal oxide.

Calcination

The process of heating a carbonate ore strongly in limited air to convert it into a metal oxide.

Thermite Reaction

A highly exothermic displacement reaction between iron(III) oxide and aluminium powder used to weld railway tracks.

Galvanisation

A protective method against rusting in which a thin layer of zinc is applied onto iron or steel objects.

Alloy

A homogeneous mixture of two or more metals, or a metal and a non-metal.

Covalent Bond

A chemical bond formed by the mutual sharing of valence electron pairs between two atoms.

Catenation

The unique property of carbon to form stable covalent bonds with other carbon atoms, creating long chains, branched structures, or rings.

Homologous Series

A series of organic compounds with the same functional group and similar chemical properties, where consecutive members differ by a $-CH_2-$ unit.

Functional Group

An atom or group of atoms attached to a carbon chain that dictates the specific chemical properties of the organic compound.

Saponification

The chemical reaction of an ester with an alkali (like sodium hydroxide) to yield an alcohol and a sodium salt of a carboxylic acid (soap).

Döbereiner's Triad

A group of three chemically similar elements where the atomic mass of the middle element is approximately equal to the average atomic mass of the other two.

Newlands' Law of Octaves

An arrangement of elements in increasing atomic mass where the properties of every eighth element are a repetition of the first.

Modern Periodic Law

The principle stating that the physical and chemical properties of elements are periodic functions of their atomic numbers.

Autotrophic Nutrition

A mode of nutrition in which organisms manufacture their own food from simple inorganic substances like $CO_2$ and $H_2O$.

Heterotrophic Nutrition

A mode of nutrition in which organisms depend on pre-formed organic compounds from other living beings.

Transpiration

The process of loss of water in the form of water vapour from the stomata of aerial plant parts.

Translocation

The transport of soluble products of photosynthesis through the phloem tissue to various parts of the plant.

Peristaltic Movement

The rhythmic wave-like contractions and relaxations of muscles lining the alimentary canal that push food forward.

Nephron

The functional structural filtration unit of the mammalian kidney responsible for urine formation.

Reflex Arc

The complete neural pathway followed by nerve impulses during an involuntary, rapid reflex action.

Synapse

The microscopic physical gap between two adjacent neurons where nerve signals pass chemically via neurotransmitters.

Phototropism

The growth or directional movement of plant parts in direct response to light stimuli.

Geotropism

The growth or directional movement of plant parts in response to the gravitational pull of the earth.

Speciation

The evolutionary process through which new and distinct biological species emerge from existing populations.

Homologous Organs

Organs in different species that share a basic anatomical structure and origin, but perform different functions.

Analogous Organs

Organs in different species that have different structural designs and origins but perform similar functions.

Focal Length

The distance between the pole/optical centre and the principal focus of a spherical mirror or lens.

Refractive Index

The ratio of the speed of light in a vacuum (or air) to the speed of light in a given medium ($n = \frac{c}{v}$).

Power of a Lens

The measure of the degree of convergence or divergence of light rays by a lens, equal to the reciprocal of its focal length in meters ($P = \frac{1}{f}$).

Myopia

A vision defect where a person can see nearby objects clearly but cannot focus on distant objects, corrected using a concave lens.

Hypermetropia

A vision defect where a person can see distant objects clearly but struggles to focus on nearby objects, corrected using a convex lens.

Dispersion of Light

The phenomenon of splitting a beam of white light into its constituent spectrum of seven colours upon passing through a glass prism.

Tyndall Effect

The scattering of a beam of light by colloidal particles, making the path of light visible.

Electric Current

The quantity of electric charge flowing through a cross-section of a conductor per unit time ($I = \frac{Q}{t}$).

Ohm's Law

The statement that the potential difference across a metallic conductor is directly proportional to the current flowing through it at constant temperature ($V = I \times R$).

Electrical Resistivity

An intrinsic material property that measures the opposition to electric current flow, given by $\rho = \frac{R \times A}{l}$.

Joule's Law of Heating

States that the heat produced in a resistor is directly proportional to the square of current, resistance, and time ($H = I^2 \times R \times t$).

Solenoid

A cylindrical coil formed by wrapping numerous insulated copper wire turns, creating a uniform magnetic field when current flows.

Electromagnetic Induction

The phenomenon of inducing an electric current in a circuit by varying the magnetic field passing through it.

Biological Magnification

The progressive accumulation of non-biodegradable toxic substances at higher levels within a food chain.

Sustainable Development

Development that fulfills current human needs without compromising the capacity of future generations to satisfy their own needs.