Difference Between - Science Comparisons
The exam favourite "distinguish between" questions, answered clearly. Side-by-side comparison tables for Class 11 & 12 Physics, Chemistry, Biology and Maths - each with a one-line answer, a full table, and FAQs.
βοΈ Physics
Speed vs Velocity
Speed is a scalar quantity that measures how fast an object moves (magnitude only); velocity is a vector quantity that measures how fast and in which direction it moves.
See the difference β βοΈ PhysicsDistance vs Displacement
Distance is the total length of the path travelled (scalar, always positive); displacement is the shortest straight-line distance from start to end, with direction (vector).
See the difference β βοΈ PhysicsMass vs Weight
Mass is the amount of matter in an object (scalar, constant everywhere, measured in kg); weight is the gravitational force on that mass (vector, changes with g, measured in newtons).
See the difference β βοΈ PhysicsScalar vs Vector
A scalar has only magnitude (e.g. mass, speed, temperature); a vector has both magnitude and direction (e.g. velocity, force, displacement).
See the difference β βοΈ PhysicsAC (Alternating Current) vs DC (Direct Current)
Alternating current (AC) periodically reverses its direction and is used for power transmission; direct current (DC) flows steadily in one direction and is used in batteries and electronics.
See the difference β βοΈ PhysicsSeries Circuit vs Parallel Circuit
In a series circuit components are joined end-to-end so the same current flows through all of them; in a parallel circuit components are joined across common points so the same voltage appears across each branch.
See the difference β βοΈ PhysicsConvex Lens vs Concave Lens
A convex (converging) lens is thicker in the middle and brings light rays together to a focus (positive focal length); a concave (diverging) lens is thinner in the middle and spreads light rays apart (negative focal length).
See the difference β βοΈ PhysicsReflection vs Refraction
Reflection is the bouncing back of light from a surface into the same medium; refraction is the bending of light as it passes from one transparent medium into another due to a change in speed.
See the difference β βοΈ PhysicsLongitudinal Wave vs Transverse Wave
In a longitudinal wave the particles of the medium vibrate parallel to the direction of wave travel (compressions and rarefactions); in a transverse wave the particles vibrate perpendicular to the direction of travel (crests and troughs).
See the difference βπ§ͺ Chemistry
Ionic Bond vs Covalent Bond
An ionic bond forms by the complete transfer of electrons from a metal to a non-metal (creating ions); a covalent bond forms by the sharing of electron pairs between non-metals.
See the difference β π§ͺ ChemistrySigma (Ο) Bond vs Pi (Ο) Bond
A sigma (Ο) bond forms by head-on (axial) overlap of orbitals and is stronger; a pi (Ο) bond forms by sideways (lateral) overlap of p-orbitals and is weaker.
See the difference β π§ͺ ChemistryOxidation vs Reduction
Oxidation is the loss of electrons (or gain of oxygen / loss of hydrogen); reduction is the gain of electrons (or loss of oxygen / gain of hydrogen).
See the difference β π§ͺ ChemistryAldehyde vs Ketone
In aldehydes the carbonyl carbon is bonded to at least one hydrogen and sits at the end of the chain (βCHO); in ketones the carbonyl carbon is bonded to two carbon atoms and sits within the chain.
See the difference β π§ͺ ChemistryEndothermic Reaction vs Exothermic Reaction
Endothermic reactions absorb heat from the surroundings (ΞH is positive, surroundings cool); exothermic reactions release heat to the surroundings (ΞH is negative, surroundings warm).
See the difference β π§ͺ ChemistrySN1 Reaction vs SN2 Reaction
SN1 is a two-step reaction that goes through a carbocation intermediate, is favoured by tertiary substrates and gives racemisation; SN2 is a single-step reaction with a transition state, is favoured by primary substrates and gives inversion of configuration.
See the difference β π§ͺ ChemistryAcid vs Base
An acid donates hydrogen ions (HβΊ), tastes sour and has a pH below 7; a base accepts HβΊ (or donates OHβ» ions), tastes bitter, feels soapy and has a pH above 7.
See the difference β π§ͺ ChemistryElement vs Compound
An element is a pure substance made of only one kind of atom that cannot be broken down into simpler substances chemically; a compound is a pure substance made of two or more elements chemically combined in a fixed ratio.
See the difference βπ¬ Biology
Mitosis vs Meiosis
Mitosis produces 2 genetically identical diploid cells for growth and repair, while meiosis produces 4 genetically different haploid cells (gametes) for sexual reproduction.
See the difference β π¬ BiologyDNA vs RNA
DNA is a double-stranded molecule with deoxyribose sugar and the base thymine that stores genetic information; RNA is usually single-stranded with ribose sugar and the base uracil, and carries out protein synthesis.
See the difference β π¬ BiologyProkaryotic Cell vs Eukaryotic Cell
Prokaryotic cells have no membrane-bound nucleus or organelles and are small (1β10 ΞΌm), while eukaryotic cells have a true nucleus and membrane-bound organelles and are larger (10β100 ΞΌm).
See the difference β π¬ BiologyPlant Cell vs Animal Cell
Plant cells have a cellulose cell wall, chloroplasts and a large central vacuole; animal cells lack these but have centrioles and only small vacuoles.
See the difference β π¬ BiologyArtery vs Vein
Arteries carry blood away from the heart under high pressure and have thick muscular walls; veins carry blood towards the heart under low pressure, have thinner walls and valves to prevent backflow.
See the difference β π¬ BiologyXylem vs Phloem
Xylem transports water and minerals from roots to leaves through mostly dead cells (one direction, upward); phloem transports food (sugars) throughout the plant through living cells (both directions).
See the difference β π¬ BiologyMitochondria vs Chloroplast
Mitochondria release energy by breaking down glucose in cellular respiration (present in all aerobic cells); chloroplasts trap light energy to make glucose in photosynthesis (present only in green plants and algae).
See the difference β π¬ BiologyRod Cells vs Cone Cells
Rod cells enable vision in dim light and detect only shades of grey (black-and-white); cone cells enable vision in bright light and detect colour.
See the difference β π¬ BiologyEndocrine Gland vs Exocrine Gland
Endocrine glands are ductless and pour hormones directly into the blood; exocrine glands have ducts that carry their secretions to a specific surface or cavity.
See the difference β π¬ BiologyInnate Immunity vs Acquired Immunity
Innate (non-specific) immunity is present from birth and responds the same way to all pathogens without memory; acquired (specific) immunity develops after exposure, is pathogen-specific and has memory.
See the difference β π¬ BiologySystole vs Diastole
Systole is the contraction phase of the heart when blood is pumped out of the chambers; diastole is the relaxation phase when the chambers refill with blood.
See the difference β π¬ BiologyCβ Plants vs Cβ Plants
Cβ plants fix COβ directly via the Calvin cycle into a 3-carbon compound (3-PGA) and undergo photorespiration; Cβ plants first fix COβ into a 4-carbon compound (OAA) using Kranz anatomy, minimising photorespiration.
See the difference β π¬ BiologyAerobic Respiration vs Anaerobic Respiration
Aerobic respiration uses oxygen to completely break down glucose into COβ and water, releasing a large amount of energy (~38 ATP); anaerobic respiration occurs without oxygen, gives incomplete breakdown and releases far less energy (~2 ATP).
See the difference β