General Science

What is General Science?

General Science is the study of basic scientific ideas that explain the natural world and everyday life. It includes Physics, Chemistry, Biology, human body, health, nutrition, environment, inventions and applications of science in daily activities.

In competitive exams, General Science questions are usually based on simple concepts, daily-life applications, important discoveries, human body systems, diseases, vitamins, scientific instruments, basic laws, common chemicals and biological processes.

Simple idea: Science explains why things happen, how things work, and how knowledge can be used to improve life.

Branch	What it Studies	Examples
Physics	Matter, energy, motion, force, light, heat, sound and electricity.	Gravity, lenses, current, magnetism
Chemistry	Substances, elements, compounds, reactions and materials.	Acids, bases, salts, metals, gases
Biology	Living organisms, cells, plants, animals and human body.	Respiration, digestion, blood, diseases
Everyday Science	Scientific principles used in daily life.	Pressure cooker, refrigerator, thermometer
Applied Science	Use of science in technology, medicine and industry.	Vaccines, satellites, computers, solar cells

“Science becomes easier when every fact is connected with a reason, process, example and application.”

Exam Preparation Tip

Key areas

Physics basics and everyday applications
Chemistry basics, acids, bases and materials
Biology basics, cells, plants and animals
Human body systems and organs
Diseases, immunity and vaccines
Nutrition, vitamins and deficiency diseases
Scientific instruments and inventions
Environmental and daily-life science

Physics Chemistry Biology Health Inventions

Scientific Method

The scientific method is a systematic way of understanding nature. It involves observation, asking questions, forming a hypothesis, testing through experiment, collecting data, drawing conclusions and applying the result.

Step	Meaning	Simple Example
Observation	Carefully noticing an event or condition.	Plants grow better in sunlight.
Question	Asking why or how something happens.	Why do plants need sunlight?
Hypothesis	A possible explanation that can be tested.	Sunlight helps plants make food.
Experiment	Testing the hypothesis under controlled conditions.	Keep one plant in sunlight and another in darkness.
Conclusion	Result based on evidence.	Plants require sunlight for healthy growth.

Exam approach: Scientific method questions usually test observation, experiment, hypothesis, evidence and conclusion.

Visual Understanding: Branches of Science

This diagram shows the major areas covered under General Science.

Important Science Vocabulary

Matter: Anything that has mass and occupies space.
Energy: Capacity to do work.
Force: Push or pull acting on an object.
Atom: Smallest unit of an element.
Cell: Basic structural and functional unit of life.
Organism: A living thing.

Common Mistakes in General Science

Confusing mass and weight.
Confusing heat and temperature.
Mixing acids and bases.
Thinking bacteria and viruses are the same.
Confusing vitamins with minerals.
Assuming all diseases are infectious.

Physics Basics

Physics studies matter, energy and their interactions. In General Science, Physics questions commonly come from force, motion, gravity, work, energy, heat, light, sound, electricity, magnetism and scientific instruments.

Concept	Meaning	Everyday Example
Motion	Change in position of an object with time.	A moving car or running person.
Force	A push or pull that can change motion or shape.	Pushing a door.
Gravity	Force by which objects are attracted toward Earth.	Objects falling downward.
Work	Work is done when force causes displacement.	Lifting a bag.
Energy	Capacity to do work.	Food gives energy to body.
Power	Rate of doing work.	Higher watt bulb uses more power.

Exam tip: Physics questions are often application-based. Connect each concept with a daily-life example.

Heat and Temperature

Heat is a form of energy that flows from a hotter body to a colder body. Temperature measures how hot or cold an object is. Heat and temperature are related but not the same.

Conduction: Heat transfer through solids.
Convection: Heat transfer through fluids.
Radiation: Heat transfer without medium.
Thermometer: Measures temperature.
Expansion: Most substances expand on heating.

Light

Light is a form of energy that enables vision. It travels in straight lines and undergoes reflection, refraction and dispersion.

Reflection: Bouncing back of light.
Refraction: Bending of light.
Dispersion: Splitting of white light into colours.
Convex lens: Used in magnifying glass.
Concave mirror: Used in shaving mirror and headlights.

Sound

Sound is produced by vibrating objects. It needs a medium such as air, water or solids to travel. Sound cannot travel through vacuum.

Frequency: Number of vibrations per second.
Pitch: Depends on frequency.
Loudness: Depends on amplitude.
Echo: Reflected sound heard again.
Ultrasound: Sound above human hearing range.

Electricity and Magnetism

Electricity is the flow of electric charge. It is used in lighting, heating, machines, communication, transport and household appliances. Magnetism is the property by which certain materials attract iron and other magnetic substances.

Term	Meaning	Exam Focus
Current	Flow of electric charge.	Measured in ampere.
Voltage	Electric potential difference.	Measured in volt.
Resistance	Opposition to flow of current.	Measured in ohm.
Conductor	Allows current to pass easily.	Copper, aluminium.
Insulator	Does not allow current to pass easily.	Rubber, plastic, wood.
Fuse	Safety device that breaks circuit during excess current.	Electrical safety.
Electromagnet	Temporary magnet produced by electric current.	Electric bell, cranes.

Shortcut: Current flows through conductors; insulators prevent current flow; fuse protects circuits.

Important Scientific Instruments

Instrument	Used For	Exam Clue
Thermometer	Measuring temperature.	Heat and body temperature.
Barometer	Measuring atmospheric pressure.	Weather forecasting.
Hygrometer	Measuring humidity.	Moisture in air.
Ammeter	Measuring electric current.	Ampere.
Voltmeter	Measuring voltage.	Volt.
Seismograph	Recording earthquake waves.	Earthquake measurement.
Microscope	Viewing very small objects.	Cells and microorganisms.
Telescope	Viewing distant objects.	Astronomy.

Chemistry Basics

Chemistry is the study of substances, their composition, structure, properties and changes. In General Science, Chemistry questions commonly come from atoms, molecules, elements, compounds, acids, bases, salts, metals, non-metals, gases, fuels and everyday chemicals.

Term	Meaning	Example
Atom	Smallest unit of an element that retains its properties.	Hydrogen atom, oxygen atom.
Molecule	Group of atoms chemically bonded together.	Water molecule, oxygen molecule.
Element	Pure substance made of one type of atom.	Iron, oxygen, gold.
Compound	Substance formed by chemical combination of elements.	Water, carbon dioxide, salt.
Mixture	Combination of substances not chemically bonded.	Air, soil, salt water.
Chemical Reaction	Process in which new substances are formed.	Rusting, burning, digestion.

Exam tip: Chemistry questions often test common substances, formulas, uses, reactions and daily-life examples.

Acids, Bases and Salts

Acids, bases and salts are important chemical substances used in daily life. Their properties can be identified using indicators. The pH scale is used to measure how acidic or basic a substance is.

Type	Properties	Examples
Acid	Sour taste, turns blue litmus red.	Lemon juice, vinegar, hydrochloric acid.
Base	Bitter taste, slippery feel, turns red litmus blue.	Soap solution, lime water, sodium hydroxide.
Salt	Formed when acid reacts with base.	Sodium chloride, baking soda.
Indicator	Substance used to detect acid or base.	Litmus, phenolphthalein, methyl orange.
pH Scale	Measures acidity or basicity.	Below 7 acidic, 7 neutral, above 7 basic.

Shortcut: Acid turns blue litmus red; base turns red litmus blue.

Metals and Non-Metals

Point	Metals	Non-Metals
Appearance	Generally shiny.	Generally dull.
Conductivity	Good conductors of heat and electricity.	Poor conductors, except graphite.
Malleability	Can be beaten into sheets.	Generally brittle.
Ductility	Can be drawn into wires.	Usually not ductile.
Examples	Iron, copper, aluminium.	Carbon, sulphur, oxygen.

Important Gases

Gas	Important Use / Feature
Oxygen	Supports respiration and burning.
Carbon Dioxide	Used by plants in photosynthesis; used in fire extinguishers.
Nitrogen	Major component of air; used in fertilizers.
Hydrogen	Lightest gas; used in fuel cells and industries.
Helium	Used in balloons and scientific applications.
Chlorine	Used for water purification in controlled amounts.

Everyday Chemicals and Their Uses

Common Name	Chemical Name / Main Component	Use
Common Salt	Sodium chloride	Food, preservation, chemical industry.
Baking Soda	Sodium bicarbonate	Baking, antacid, cleaning.
Washing Soda	Sodium carbonate	Cleaning and water softening.
Bleaching Powder	Calcium oxychloride	Disinfection and bleaching.
Plaster of Paris	Calcium sulphate hemihydrate	Plaster casts, decoration, moulds.
Vinegar	Acetic acid solution	Food and preservation.

Biology Basics

Biology is the study of living organisms. It includes cells, tissues, organs, plants, animals, microorganisms, reproduction, nutrition, respiration, excretion, heredity, health and environment.

Concept	Meaning	Exam Focus
Cell	Basic structural and functional unit of life.	Plant and animal cells.
Tissue	Group of similar cells performing a function.	Muscle tissue, nervous tissue.
Organ	Structure made of tissues performing a specific function.	Heart, lungs, kidney.
Organ System	Group of organs working together.	Digestive system, respiratory system.
Photosynthesis	Plants prepare food using sunlight, carbon dioxide and water.	Chlorophyll, oxygen release.
Respiration	Process of releasing energy from food.	Oxygen, carbon dioxide, energy.

Exam tip: Biology questions often test function, organ, disease, vitamin, microorganism and daily-life health concept.

Human Body Systems

The human body works through different organ systems. Each system performs a specific function, but all systems coordinate to maintain life. For exams, learn the main organ and function of each system.

System	Main Organs	Main Function
Digestive System	Mouth, stomach, intestine, liver, pancreas	Digestion and absorption of food.
Respiratory System	Nose, trachea, lungs	Exchange of oxygen and carbon dioxide.
Circulatory System	Heart, blood, blood vessels	Transport of oxygen, nutrients and wastes.
Nervous System	Brain, spinal cord, nerves	Control, coordination and response.
Excretory System	Kidneys, ureters, urinary bladder	Removal of nitrogenous wastes.
Skeletal System	Bones and joints	Support, movement and protection.
Endocrine System	Hormone-secreting glands	Chemical coordination through hormones.

Shortcut: Heart pumps blood; lungs exchange gases; kidneys filter blood; brain controls body functions.

Blood

RBC: Carries oxygen with haemoglobin.
WBC: Helps fight infection.
Platelets: Help in blood clotting.
Plasma: Liquid part of blood.
Blood group: Important for transfusion.
Haemoglobin: Iron-containing pigment in RBC.

Brain and Nerves

Cerebrum: Thinking, memory and voluntary actions.
Cerebellum: Balance and coordination.
Medulla: Controls involuntary actions.
Spinal cord: Carries nerve signals.
Reflex action: Quick automatic response.
Neuron: Nerve cell.

Hormones and Glands

Insulin: Regulates blood sugar.
Thyroxine: Regulates metabolism.
Adrenaline: Emergency hormone.
Pituitary: Master gland.
Pancreas: Secretes insulin.
Thyroid: Produces thyroxine.

Plant Science Basics

Root: Absorbs water and minerals.
Stem: Supports plant and transports substances.
Leaf: Main site of photosynthesis.
Flower: Reproductive part of plant.
Stomata: Tiny openings for gas exchange.
Chlorophyll: Green pigment needed for photosynthesis.
Transpiration: Loss of water vapour from leaves.

Microorganisms

Bacteria: Some useful, some disease-causing.
Viruses: Very small infectious agents.
Fungi: Include yeast, moulds and mushrooms.
Protozoa: Single-celled organisms; some cause diseases.
Algae: Simple plant-like organisms.
Useful microbes: Used in curd, fermentation and antibiotics.
Pathogens: Disease-causing microorganisms.

Health and Diseases

Health means physical, mental and social well-being. Disease is a condition that disturbs the normal functioning of the body. Diseases may be infectious or non-infectious. For exams, learn disease, causative agent, mode of spread, organ affected and prevention.

Disease Type	Meaning	Examples
Infectious Disease	Caused by pathogens and can spread from person to person or through vectors.	Tuberculosis, malaria, dengue, influenza.
Non-Infectious Disease	Does not spread from one person to another.	Diabetes, hypertension, cancer.
Deficiency Disease	Caused by lack of nutrients.	Rickets, scurvy, anaemia.
Genetic Disease	Caused by genetic factors.	Haemophilia, sickle cell anaemia.
Lifestyle Disease	Linked with diet, inactivity, stress and habits.	Obesity, diabetes, heart disease.

Exam tip: Do not assume all diseases are infectious. Diabetes and hypertension are non-infectious.

Common Diseases and Causes

Disease	Cause / Agent	Important Point
Malaria	Protozoan parasite spread by female Anopheles mosquito.	Vector-borne disease.
Dengue	Virus spread by Aedes mosquito.	Mosquito-borne viral disease.
Tuberculosis	Bacterial infection.	Mainly affects lungs.
Typhoid	Bacterial disease.	Spreads through contaminated food and water.
Cholera	Bacterial disease.	Water-borne disease causing severe diarrhoea.
Rabies	Virus.	Usually transmitted through bite of infected animal.
Diabetes	Problem related to insulin and blood sugar regulation.	Non-infectious disease.
Anaemia	Often caused by iron deficiency.	Low haemoglobin.

Shortcut: Malaria and dengue are vector-borne; cholera and typhoid are linked with contaminated food or water.

Immunity and Vaccination

Immunity is the body’s ability to resist disease. Vaccines help the immune system recognize pathogens and prepare protection against future infection.

Innate immunity: Natural defence present from birth.
Acquired immunity: Develops after infection or vaccination.
Antibody: Protective protein produced by immune system.
Vaccine: Prepares body to fight disease.
Booster dose: Strengthens immune response.
Herd immunity: Community-level protection when many are immune.

Prevention of Diseases

Clean drinking water and sanitation.
Hand washing and hygiene.
Vaccination where recommended.
Balanced diet and regular exercise.
Control of mosquitoes and vectors.
Safe food handling and proper cooking.
Early diagnosis and proper medical care.

Nutrition

Nutrition is the process by which the body obtains and uses food for energy, growth, repair and maintenance. A balanced diet contains carbohydrates, proteins, fats, vitamins, minerals, water and fibre in proper amounts.

Nutrient	Main Function	Sources
Carbohydrates	Main source of energy.	Rice, wheat, potato, sugar.
Proteins	Growth and repair of body tissues.	Pulses, milk, eggs, fish, meat, soybean.
Fats	Energy storage and insulation.	Oil, ghee, butter, nuts.
Vitamins	Protective nutrients needed in small amounts.	Fruits, vegetables, milk, sunlight for vitamin D.
Minerals	Body functions such as blood, bones and nerves.	Iron, calcium, iodine-rich foods.
Water	Transport, temperature regulation and metabolism.	Drinking water, fruits, vegetables.

Exam approach: Nutrition questions usually connect nutrient, source, function and deficiency disease.

Vitamins and Deficiency Diseases

Vitamin / Mineral	Function	Deficiency Disease / Problem
Vitamin A	Vision and healthy skin.	Night blindness.
Vitamin B1	Nerve function and energy metabolism.	Beriberi.
Vitamin C	Immunity and wound healing.	Scurvy.
Vitamin D	Bone health and calcium absorption.	Rickets in children.
Vitamin K	Blood clotting.	Bleeding tendency.
Iron	Haemoglobin formation.	Anaemia.
Iodine	Thyroid hormone formation.	Goitre.
Calcium	Bones and teeth.	Weak bones and teeth.

Everyday Science

Everyday science explains the scientific principles behind common objects and activities. Many exam questions are asked from daily-life applications because they test understanding rather than memorisation.

Everyday Example	Scientific Principle	Exam Focus
Pressure Cooker	Increase in pressure raises boiling point of water.	Food cooks faster.
Refrigerator	Removes heat from inside and releases it outside.	Cooling principle.
Thermos Flask	Reduces heat transfer by conduction, convection and radiation.	Heat insulation.
Electric Fuse	Melts when excessive current flows.	Electrical safety.
Rainbow	Dispersion, refraction and reflection of sunlight in water droplets.	Optics.
Soap Cleaning	Soap helps remove grease and dirt by emulsification.	Surface action.
Rusting of Iron	Reaction of iron with oxygen and moisture.	Oxidation and corrosion.

Exam tip: In everyday science, always ask: which scientific principle is working here?

Important Inventions and Discoveries

Inventions and discoveries are often asked in direct GK questions. Students should remember the invention or discovery, the scientist or inventor, and the field of application.

Invention / Discovery	Associated Person	Field / Importance
Telephone	Alexander Graham Bell	Communication.
Electric Bulb	Thomas Edison	Lighting technology.
Penicillin	Alexander Fleming	Antibiotic medicine.
Radioactivity	Henri Becquerel; Marie Curie and Pierre Curie contributed greatly.	Nuclear science.
Gravity	Isaac Newton	Physics and motion.
Raman Effect	C. V. Raman	Scattering of light.
Smallpox Vaccine	Edward Jenner	Vaccination and immunity.
Periodic Table	Dmitri Mendeleev	Classification of elements.

Shortcut: Bell - Telephone, Edison - Bulb, Fleming - Penicillin, Jenner - Vaccine, Mendeleev - Periodic Table.

High-Yield Revision Bank

Physics Must-Remember

Force - push or pull
Gravity - attraction toward Earth
Heat flows from hot to cold
Sound needs medium
Fuse protects circuit
Lens bends light

Chemistry Must-Remember

Acid turns blue litmus red
Base turns red litmus blue
Water is a compound
Air is a mixture
Rusting is oxidation
pH 7 is neutral

Biology Must-Remember

Cell is unit of life
RBC carries oxygen
WBC fights infection
Kidney filters blood
Vitamin C deficiency causes scurvy
Iron deficiency causes anaemia

Practice

A) Multiple Choice Questions

The basic unit of life is:
Cell Atom Tissue Organ
Vitamin C deficiency causes:
Scurvy Rickets Night blindness Goitre
Sound cannot travel through:
Vacuum Air Water Solid
Acid turns:
Blue litmus red Red litmus blue Water into salt Oxygen into nitrogen
Penicillin was discovered by:
Alexander Fleming Isaac Newton C. V. Raman Edward Jenner

B) Higher-Order Questions

Explain the difference between heat and temperature. (Hint: Heat is energy; temperature measures hotness or coldness.)
Differentiate between infectious and non-infectious diseases. (Hint: Spread from person to person versus non-spreading.)
Explain why a pressure cooker cooks food faster. (Hint: Pressure increases boiling point.)
Differentiate between metals and non-metals. (Hint: Conductivity, shine, malleability, ductility.)
Classify the following: RBC, WBC, platelet, plasma. (Hint: Components of blood.)

Show Suggested Answers

Multiple Choice

Cell
The cell is the basic structural and functional unit of life.
Scurvy
Deficiency of vitamin C causes scurvy.
Vacuum
Sound requires a medium and cannot travel through vacuum.
Blue litmus red
Acids turn blue litmus paper red.
Alexander Fleming
Penicillin was discovered by Alexander Fleming.

Higher-Order Answers

Heat and temperature:
Heat is a form of energy that flows from a hotter body to a colder body. Temperature measures the degree of hotness or coldness of a body.
Infectious and non-infectious diseases:
Infectious diseases are caused by pathogens and can spread. Non-infectious diseases do not spread from person to person and may be caused by lifestyle, deficiency or genetic factors.
Pressure cooker:
In a pressure cooker, pressure increases, which raises the boiling point of water. Higher temperature cooks food faster.
Metals and non-metals:
Metals are generally shiny, malleable, ductile and good conductors. Non-metals are generally dull, brittle and poor conductors.
Blood components:
RBC carries oxygen, WBC fights infection, platelets help clotting, and plasma is the liquid part of blood.

Concept Matching

Thermometer → Temperature
Barometer → Atmospheric pressure
Vitamin A deficiency → Night blindness
Iron deficiency → Anaemia
Chlorophyll → Photosynthesis
Fuse → Electrical safety

General Science becomes easier when every fact is connected with function, cause, example and daily-life application.

Learning Modules