Class 4 Science - Complete Notes

🌟 CLASS 4 SCIENCE 🌟

COMPLETE STUDY NOTES

Chapter 1 to Chapter 10

📚 Detailed Concepts
🎯 Important MCQs
📝 Exam Ready Material

Based on Latest Curriculum

📑 TABLE OF CONTENTS

Chapter No.	Chapter Name	Page
1	Our Body - The Amazing Machine	1
2	Characteristics and Needs of Living Things	15
3	Food and Health	22
4	Living Things and Their Environment	35
5	Matter and Its States	45
6	Heat and Its Measurement	55
7	Force and Machine	62
8	Sound	67
9	Electricity and Magnetism	75
10	Movements of the Earth	88

🔬 INTRODUCTION TO SCIENCE

Science Latin word "Scientia" se aaya hai jiska matlab hai "Knowledge" ya "Jaanna".

Science ka matlab hai duniya ko samajhna - cheezein kaise kaam karti hain, kyun karti hain, aur unke peeche kya reason hai.

🧪 SCIENCE - TWO MAIN BRANCHES

                        SCIENCE
                           │
            ┌──────────────┴──────────────┐
            │                             │
        BIOLOGY                        PHYSICS
           │                              │
    Living things                    Non-living things
    (Jeevit cheezein)                Energy, Force, Matter
           │                              │
    Humans, Animals,                  Heat, Light,
    Plants, etc.                      Sound, Magnets

Science ke do main branches: Biology aur Physics

📖 CHAPTER 1: OUR BODY - THE AMAZING MACHINE

Humara body ek perfect machine hai. Jaise kisi machine mein alag-alag parts hote hain aur har part ka apna kaam hota hai, waise hi body mein alag-alag systems hain.

System	Kaam	Main Parts
Nervous System	Control karna	Brain, Spinal cord, Nerves
Digestive System	Khana digest karna	Mouth, Stomach, Intestines
Respiratory System	Saans lena	Nose, Trachea, Lungs
Circulatory System	Blood pump karna	Heart, Blood vessels
Skeletal System	Shape dena, support	Bones, Joints
Muscular System	Movement	Muscles
Excretory System	Waste nikaalna	Kidneys, Skin
Integumentary System	Protection	Skin

SYSTEM 1: NERVOUS SYSTEM (Control System)

🧠 NERVOUS SYSTEM

                        BRAIN (Control Center)
                            │
                    SPINAL CORD (Messages)
                            │
            ┌───────────────┴───────────────┐
            │                               │
      SENSORY NERVES                  MOTOR NERVES
      (Body → Brain)                  (Brain → Body)
            │                               │
    Feel: "Garam hai!"              Action: "Haath hatao!"

Nervous System: Brain, Spinal Cord, aur Nerves

🧠 BRAIN (Dimag)

Location: Head mein, skull ke andar protected
Weight: ~1.4 kg (adult)
Cells: ~100 billion neurons

Brain ke 3 Main Parts:

Part	Location	Function
Cerebrum	Brain ka sabse bada part (top)	Sochna, yaad rakhna, decisions lena
Cerebellum	Brain ke peeche (back)	Balance, coordination
Brain Stem	Brain ke neeche	Heartbeat, breathing (automatic)

📞 NERVES - TYPES (IMPORTANT)

Type	Direction	Function	Example
SENSORY NERVES (Afferent)	Body → Brain	Feelings carry karna	"Garam chulhe ko haath laga - brain ko batati hai GARAM HAI!"
MOTOR NERVES (Efferent)	Brain → Body	Actions carry karna	"Brain kehti hai Haath hatao! - muscle ko batati hai"

❓ DONO ALAG KYUN HAIN?

Division of Labor: Kaam ka baantwara - ek information collect, doosra action
Speed: Ek hi nerve mein hote to messages collide karte
Control: Brain ko sochne ka time milta hai

Real Life Example - Needle Touch:

Skin receptors ne mehsoos kiya "kuch teekha hai"
SENSORY NERVE ye message brain tak le gayi
Brain ne decision liya "Haath hatao!"
MOTOR NERVE ye command muscle tak le gayi
Muscle ne action kiya - haath hat gaya

⏱️ Total time: Milliseconds mein!

🤕 HEADACHE KA MYSTERY

Sawaal: Headache mein brain ko dard kyun nahi hota?

Jawaab: Brain ke andar pain receptors nahi hote. Dard meninges mein hota hai - ye brain ke surrounding mein ek protective layer hai. Isliye brain surgery ke waqt patient awake reh sakta hai!

SYSTEM 2: DIGESTIVE SYSTEM (Food Processing Factory)

🍽️ DIGESTIVE SYSTEM - POORI YATRA

        MOUTH (Start) → Teeth + Saliva
              ↓
        ESOPHAGUS (Food Pipe)
              ↓
        STOMACH (Acid + Enzymes)
              ↓
        SMALL INTESTINE (6-7 meters)
        Nutrients Absorption
              ↓
        LARGE INTESTINE (1.5 meters)
        Water Absorption
              ↓
        RECTUM → ANUS (End)

Food ka safar: Mouth se Anus tak

Organ	Kya Hota Hai	Time	Key Enzyme/Chemical
Mouth	Teeth se chhota karna, Saliva mix	1 min	Amylase (Carbs todta hai)
Esophagus	Food push neeche (peristalsis)	5-10 sec	-
Stomach	HCl acid, Pepsin - Protein todna	2-4 hours	HCl, Pepsin
Small Intestine	Nutrients absorption (Villi se)	4-6 hours	Bile, Pancreatic juice
Large Intestine	Water absorption	12-24 hours	Bacteria
Anus	Waste exit	-	-

⭐ IMPORTANT POINTS

Digestive system START: Mouth se (Stomach nahi!)
Small Intestine length: 6-7 meters (4-5 bachchon ki height)
Villi: Chhoti finger-like structures jo surface area badhaati hain
Liver: Bile banata hai (fat digest karne ke liye)
Ulcer: Mucus kam ho to stomach acid stomach ko digest karne lage

SYSTEM 3: RESPIRATORY SYSTEM (Oxygen Department)

🌬️ RESPIRATORY SYSTEM

        NOSE (Filter + Warm)
              ↓
        TRACHEA (Windpipe)
              ↓
        BRONCHI (Two tubes)
           ↙      ↘
    LEFT LUNG   RIGHT LUNG
    (2 lobes)   (3 lobes)
              ↓
        BRONCHIOLES (Small tubes)
              ↓
        ALVEOLI (Gas Exchange)

Air ka safar: Nose se Alveoli tak

Part	Function
Nose	Air filter, warm, moist
Trachea	Clean air ka passage (C-shaped rings)
Bronchi	Two tubes - left aur right lung ke liye
Bronchioles	Smaller tubes (tree branches jaisi)
Alveoli	Gas exchange - Oxygen ↔ CO₂
Lungs	Right: 3 lobes, Left: 2 lobes
Diaphragm	Muscle jo breathing mein help karta hai
Ribcage	24 ribs - lungs ki protection

💨 ALVEOLI KE BAARE MEIN

Count: ~300 million alveoli
Surface area: 70-100 square meters (tennis court jitna!)
Function: Yahan oxygen blood mein jaati hai, CO₂ bahar aati hai

🫁 ASTHMA

What is it? Bronchioles narrow ho jaati hain (inflammation + mucus)

Symptoms: Wheezing, coughing, breathlessness

Triggers: Allergies, pollution, exercise, cold air

SYSTEM 4: CIRCULATORY SYSTEM (Transport Department)

❤️ HEART AND BLOOD CIRCULATION

        RIGHT ATRIUM ← Body se blood
              ↓
        RIGHT VENTRICLE → Lungs (Oxygen lene)
              ↓
        LEFT ATRIUM ← Lungs se blood
              ↓
        LEFT VENTRICLE → Poori body mein
        (Strongest chamber)

Heart ke 4 chambers

Aspect	Details
Heart rate	72 beats/minute (average adult)
Heart chambers	4 (Right Atrium, Right Ventricle, Left Atrium, Left Ventricle)
Arteries	Heart se body tak (oxygen-rich blood)
Veins	Body se heart tak (oxygen-poor blood)
Capillaries	Chhoti vessels - connect arteries & veins

🩸 BLOOD COMPONENTS

Component	Percentage	Function
Plasma	55%	Liquid part, carries nutrients
Red Blood Cells	44%	Oxygen carry (hemoglobin), Iron se bante hain
White Blood Cells	<1%	Immunity, fight infection
Platelets	<1%	Blood clotting

SYSTEM 5: SKELETAL SYSTEM (Support Department)

🦴 BONES AND JOINTS

        SKULL (22 bones)
           │
        SPINE (26 vertebrae)
           │
    RIBCAGE (24 ribs + sternum)
           │
    ARMS (64 bones)    LEGS (62 bones)
           │                │
    HANDS (bones)     FEET (bones)

Human Skeleton: 206 bones total

Body Part	Bones
Skull	22
Spine	26
Ribs + Breastbone	25
Arms + Shoulders	64
Legs + Hips	62
Ears (inside)	6
TOTAL	206

📌 BONE FACTS

Baby bones: ~300 (fuse ho kar 206 ban jaate hain)
Smallest bone: Stapes (ear mein) - 2.5 mm
Largest bone: Femur (thigh bone)

🤸 JOINTS (Jahan do bones milti hain)

Joint Type	Movement	Example
Hinge Joint	Ek direction (like door)	Elbow, Knee
Ball & Socket	Sabhi directions	Shoulder, Hip
Pivot Joint	Rotate (ghoomna)	Neck
Gliding Joint	Slide over each other	Wrist, Ankle
Fixed Joint	No movement	Skull bones

SYSTEM 6: SKIN (Integumentary System)

🧴 SKIN LAYERS

        EPIDERMIS (Top layer)
        Dead cells, melanin
              ↓
        DERMIS (Middle layer)
        Blood vessels, nerves, sweat glands
              ↓
        SUBCUTANEOUS (Bottom layer)
        Fat cells, insulation

Skin ki 3 layers - thickness 2 mm

Aspect	Details
Largest organ	Skin
Thickness	2 mm average
Thinnest	Eyelids (0.5 mm)
Thickest	Soles (4 mm)
Functions	Protection, Temperature control, Sensation, Vitamin D synthesis

SYSTEM 7: TEETH

🦷 TYPES OF TEETH

        INCISORS (8) - Cutting (Front)
        CANINES (4) - Tearing (Pointed)
        PREMOLARS (8) - Crushing
        MOLARS (12) - Grinding (Back)

Permanent teeth: 32 total

Type	Count	Age
Milk Teeth (Primary)	20	6 months - 6 years
Permanent Teeth	32	6 years onwards

SYSTEM 8: EARS

👂 STRUCTURE OF EAR

        EXTERNAL EAR (Pinna) - Sound collect
              ↓
        EAR CANAL - Sound to eardrum
              ↓
        EARDRUM - Vibrates
              ↓
        MIDDLE EAR (3 small bones) - Amplify
              ↓
        INNER EAR (Cochlea) - To electrical signals
              ↓
        AUDITORY NERVE - To brain

Ear ke parts

🐘 ELEPHANT EARS

African elephants ke ears Asian elephants se bade hote hain
Ears mein blood vessels hote hain
Flap karne se cooling hoti hai - temperature control

📝 CHAPTER 1 - IMPORTANT MCQs

Body ka control system kaunsa hai? → Brain
Spinal cord kahan protect hota hai? → Backbone mein
Sensory nerves kya karti hain? → Body se brain tak message le jaati hain
Motor nerves kya karti hain? → Brain se body tak message le jaati hain
Headache mein dard kahan hota hai? → Meninges mein
Brain ko dard kyun nahi hota? → Pain receptors nahi
Digestive system ka start point? → Mouth
Saliva mein kaunsa enzyme hota hai? → Amylase
Stomach mein kaunsa acid hota hai? → HCl
Small intestine ki length? → 6-7 meters
Villi kya karte hain? → Nutrients absorption ke liye surface area badhaate hain
Paani kahan absorb hota hai? → Large intestine mein
Lungs kahan hote hain? → Chest cavity mein
Lungs ki protection? → Ribcage
Heart beats per minute? → 72
Heart ke kitne chambers hain? → 4
Blood ke components? → Plasma, RBC, WBC, Platelets
Total bones in human body? → 206
Joints kya hain? → Jahan do bones milti hain
Skin thickness? → 2 mm
Largest organ of body? → Skin
Milk teeth count? → 20
Permanent teeth count? → 32
African elephant ears? → Asian se bade
Asthma kiski disorder? → Lungs / Bronchioles

📖 CHAPTER 2: CHARACTERISTICS AND NEEDS OF LIVING THINGS

🌱 LIVING THINGS - 7 CHARACTERISTICS

        1. MOVEMENT - Harkat
        2. RESPIRATION - Saans lena
        3. SENSITIVITY - Feel karna
        4. GROWTH - Badhna
        5. REPRODUCTION - Bachhe paida karna
        6. EXCRETION - Waste nikaalna
        7. NUTRITION - Khana khana

Living things ki 7 characteristics

🧬 TRAITS

Definition: Jo humein parents se milta hai

Type	Examples
Physical Traits	Aankhon ka colour, baal ka type, height
Behavioral Traits	Habits, temperament, talents

🦋 BUTTERFLY LIFE CYCLE

BUTTERFLY LIFE CYCLE

        EGG (3-7 days)
          ↓
        LARVA / CATERPILLAR (2-3 weeks)
          ↓
        PUPA / CHRYSALIS (1-2 weeks)
          ↓
        ADULT BUTTERFLY (2-4 weeks)
          ↓
        (Cycle repeats)

Complete Metamorphosis

Stage	Also Called	Duration	Kya Hota Hai
Egg	Anda	3-7 days	Leaf par anday diye
Larva	Caterpillar	2-3 weeks	Bas khata hai, molting karta hai
Pupa	Chrysalis	1-2 weeks	Cocoon mein transformation
Adult	Butterfly	2-4 weeks	Mate karta hai, eggs deta hai

📌 IMPORTANT TERMS

Metamorphosis: Complete change of form
Molting: Caterpillar apni skin shed karta hai (kyunki stretch nahi hoti)

🐸 FROG LIFE CYCLE

FROG LIFE CYCLE

        SPAWN (Eggs) - Jelly-like
          ↓
        TADPOLE - Gills, Tail, Fish-like
          ↓
        FROGLET - Legs develop, Tail short
          ↓
        ADULT FROG - Lungs, No tail
          ↓
        (Cycle repeats)

Amphibian Life Cycle

Stage	Duration	Characteristics
Spawn	Few days	Jelly-covered eggs in water
Tadpole	6-9 weeks	Gills, tail, no legs, fish-like
Froglet	Few weeks	Legs develop, tail shortens
Adult Frog	1-4 years	Lungs, no tail, land & water

🏞️ AMPHIBIANS

"Amphi" = both, "bios" = life → Paani aur land dono jagah reh sakte hain

Examples: Frog, Salamander

📝 CHAPTER 2 - IMPORTANT MCQs

Living things ki kitni characteristics hain? → 7
Characteristics jo parents se milti hain? → Traits
Butterfly life cycle order? → Egg - Larva - Pupa - Adult
Larva ko aur kya kehte hain? → Caterpillar
Pupa ko aur kya kehte hain? → Chrysalis
Frog life cycle order? → Spawn - Tadpole - Froglet - Frog
Frog eggs ko kya kehte hain? → Spawn
Tadpole kaunsa respiratory organ use karta hai? → Gills
Adult frog kaunsa respiratory organ use karta hai? → Lungs
Frog kis category mein aata hai? → Amphibian

📖 CHAPTER 3: FOOD AND HEALTH

🥗 6 MAIN NUTRIENTS

        ┌─────────────────────┐
        │    CARBOHYDRATES    │ Quick Energy
        │     (Roti, Rice)    │
        ├─────────────────────┤
        │      PROTEINS       │ Body Building
        │    (Dal, Meat, Egg) │
        ├─────────────────────┤
        │        FATS         │ Stored Energy
        │   (Oil, Butter)     │
        ├─────────────────────┤
        │      VITAMINS       │ Protection
        │ (Fruits, Vegetables)│
        ├─────────────────────┤
        │      MINERALS       │ Body Functions
        │  (Seafood, Milk)    │
        ├─────────────────────┤
        │       WATER         │ Hydration
        │      (Pani)         │
        └─────────────────────┘

6 Essential Nutrients

🍚 CARBOHYDRATES (Quick Energy)

Function: Instant energy

Sources: Rice, Wheat, Potatoes, Sugar

Deficiency: Weakness, fatigue

🥚 PROTEINS (Body Building)

Function: Growth, repair, building blocks

Sources: Dal, Meat, Fish, Eggs, Milk

Deficiency: Marasmus, Kwashiorkor

🧈 FATS (Stored Energy)

Function: Stored energy, insulation

Sources: Oil, Butter, Ghee, Nuts

Deficiency: Weight loss

💊 VITAMINS - Complete Guide

Vitamin	Function	Sources	Deficiency Disease
Vitamin A	Eyes, skin, immunity	Carrot, Mango, Papaya	Night Blindness
Vitamin B1	Nerves, energy	Whole grains, Dal	Beriberi
Vitamin B2	Skin, eyes	Milk, Eggs	Cheilosis
Vitamin B3	Skin, digestion	Meat, Nuts	Pellagra
Vitamin B12	Blood, nerves	Eggs, Meat	Anemia
Vitamin C	Immunity, collagen	Citrus fruits, Amla	Scurvy
Vitamin D	Bones, calcium	Sunlight, Milk	Rickets
Vitamin E	Skin, hair	Nuts, Seeds	Rare
Vitamin K	Blood clotting	Green veggies	Bleeding

⚙️ MINERALS - Complete Guide

Mineral	Function	Sources	Deficiency
Iron	Hemoglobin (RBC)	Spinach, Apple	Anemia
Calcium	Bones, teeth	Milk, Curd	Rickets
Iodine	Thyroid	Iodized salt	Goiter
Copper	Blood formation	Nuts, Seafood	Kidney issues
Magnesium	Bones, muscles	Green veggies	Osteoporosis

⚠️ DEFICIENCY DISEASES

MARASMUS vs KWASHIORKOR

        MARASMUS                    KWASHIORKOR
    Protein + Calories kami        Sirf Protein kami
    Skin and bones                 Swollen belly
    Old man face                   Moon face
    Age: 6m-2y                     Age: 1-3y

Protein deficiency diseases

Disease	Deficiency	Symptoms
Night Blindness	Vitamin A	Raat mein dikhai na dena
Beriberi	Vitamin B1	Weakness, nerve issues
Scurvy	Vitamin C	Bleeding gums
Rickets	Vitamin D, Calcium	Soft bones, bowed legs
Anemia	Iron	Weakness, pale skin
Goiter	Iodine	Swollen neck
Marasmus	Protein + Calories	Severe wasting, skin and bones
Kwashiorkor	Protein	Swollen belly, edema

📝 CHAPTER 3 - IMPORTANT MCQs

Quick energy ke sources? → Carbohydrates
Body growth ke main sources? → Proteins
Protection from diseases? → Vitamins
Vitamins mainly kahan milte hain? → Fruits and vegetables
Minerals mainly kahan milte hain? → Seafood
Protein sources? → Milk, meat, eggs, pulses
Fats sources? → Oil, Butter, Ghee
Vitamin A prevents? → Night Blindness
Vitamin B prevents? → Beriberi
Vitamin C prevents? → Scurvy
Vitamin D prevents? → Rickets
Building blocks of body? → Proteins
Red blood cells kaunsa mineral banata hai? → Iron
Iron deficiency disease? → Anemia
Calcium deficiency? → Rickets
Protein deficiency diseases? → Marasmus, Kwashiorkor
Marasmus mein kya hota hai? → Weight loss, skin and bones
Kwashiorkor mein kya hota hai? → Swollen belly
Hygiene meaning? → Clean rehna
Vitamin D kaise milta hai? → Sunlight se

📖 CHAPTER 4: LIVING THINGS AND THEIR ENVIRONMENT

🌍 ENVIRONMENT

            ENVIRONMENT
        ┌─────────┴─────────┐
        │                   │
    LIVING              NON-LIVING
    (Biotic)            (Abiotic)
        │                   │
    Humans, Animals,    Air, Water,
    Plants, Bacteria    Soil, Sunlight

Environment ke do parts

⛓️ FOOD CHAIN

FOOD CHAIN EXAMPLE

    GRASS (Producer) → GRASSHOPPER (Primary Consumer) → FROG (Secondary Consumer) → SNAKE (Tertiary Consumer) → EAGLE (Tertiary)

Energy flow ek organism se doosre mein

Level	Name	Eats	Examples
1	Producers	Apna khana khud banate hain	Plants, Algae
2	Primary Consumers	Producers (plants)	Herbivores - Cow, Rabbit
3	Secondary Consumers	Primary consumers	Carnivores - Frog, Snake
4	Tertiary Consumers	Secondary consumers	Eagle, Lion
-	Decomposers	Dead things	Mushroom, Bacteria

🍃 TYPES OF CONSUMERS (By Diet)

Type	Diet	Examples
Herbivores	Plants only	Cow, Deer, Elephant
Carnivores	Animals only	Lion, Tiger, Snake
Omnivores	Plants + Animals	Humans, Bear, Crow
Insectivores	Insects	Frog, Lizard
Scavengers	Dead animals	Vulture, Hyena

🔋 ENERGY PYRAMID

10% RULE

        Tertiary Consumers (0.1% energy)
        Secondary Consumers (1% energy)
        Primary Consumers (10% energy)
        PRODUCERS (100% energy)

Har level par 90% energy heat lost

⚖️ BALANCE IN NATURE

Agar saare FROGS khatam ho jayein:

Grasshoppers ki population badh jayegi
Grasshoppers saari GRASS kha jayenge
Grass khatam → saare herbivores bhookhe
Food chain collapse

📝 CHAPTER 4 - IMPORTANT MCQs

Environment kya hai? → Natural world jo living aur non-living cheezon ko gherta hai
Herbivores kya khate hain? → Plants
Carnivores kya khate hain? → Animals
Omnivores kya khate hain? → Plants and Animals
Human beings kaunsa consumer? → Omnivores
Primary consumers kaun hain? → Herbivores
Secondary consumers kaun hain? → Carnivores jo herbivores khaate hain
Tertiary consumers kaun hain? → Jo secondary consumers khaate hain
Decomposers kya karte hain? → Dead plants/animals ko todte hain
Food chain ka sahi order? → Producer → Consumer → Decomposer
Frog kaunsa consumer? → Secondary Consumer
Decomposer ka example? → Mushroom, Mold, Bacteria
Decomposers ka key role? → Breaking down dead animals/plants
Photosynthesis kya hai? → Plants apna khana khud banate hain
Food chain mein energy kyun kam hoti jaati hai? → Har level par 90% energy heat lost

📖 CHAPTER 5: MATTER AND ITS STATES

🧊 THREE STATES OF MATTER

        SOLID          LIQUID          GAS
    ┌────────┐    ┌────────┐    ┌────────┐
    │  ████  │    │  █ █ █ │    │  █   █ │
    │  ████  │    │ █ █ █ █│    │ █   █  │
    │  ████  │    │  █ █ █ │    │   █   █│
    └────────┘    └────────┘    └────────┘
    Fixed shape   No fixed      No fixed
    Fixed volume  shape         shape/volume
                  Fixed volume

Solid, Liquid, Gas

Property	SOLID	LIQUID	GAS
Shape	Fixed	Container jaisa	Container jaisa
Volume	Fixed	Fixed	Not fixed
Particle Arrangement	Tightly packed	Loosely packed	Very far apart
Compressibility	Very low	Low	High
Example	Ice, Wood, Book	Water, Milk	Air, Steam

🔄 CHANGE OF STATE

HEATING AND COOLING

            HEATING
    SOLID ───────> LIQUID ───────> GAS
      ↑                               │
      │            COOLING             │
      └────────────────────────────────┘

Heating: Solid→Liquid→Gas, Cooling: Gas→Liquid→Solid

Process	From → To	Example
Melting	Solid → Liquid	Ice → Water
Freezing	Liquid → Solid	Water → Ice
Evaporation	Liquid → Gas	Water → Steam
Condensation	Gas → Liquid	Steam → Water
Sublimation	Solid → Gas	Camphor

🧪 MIXTURES AND SOLUTIONS

Mixture: Do ya zyada substances physically mixed (Kheer, Salad)

Solution: Homogeneous mixture jahan solute dissolve ho (Salt water)

Filtration: Mixture se solute aur solvent alag karne ka process

📝 CHAPTER 5 - IMPORTANT MCQs

Matter kya hai? → Jo jagah ghre aur jiska weight ho
States of matter kitne hain? → Three (Solid, Liquid, Gas)
Volume kya hai? → Jagah jo object gherta hai
Solid ki properties? → Fixed shape, fixed volume
Liquid ki properties? → Fixed volume, no fixed shape
Gas ki properties? → No fixed shape, no fixed volume
Solid se liquid kaise? → Heating se (Melting)
Liquid se gas kaise? → Heating se (Evaporation)
Gas se liquid kaise? → Cooling se (Condensation)
Liquid se solid kaise? → Cooling se (Freezing)
Mixture kya hai? → Solids, liquids, gases milkar
Solution kya hai? → Ek kind of mixture
Filtration kya hai? → Solute aur solvent alag karne ka process
Water kya hai? → Compound (H₂O)
Ice float kyun karta hai? → Crystal structure mein spaces hain, isliye light

📖 CHAPTER 6: HEAT AND ITS MEASUREMENT

Aspect	Details
Heat is a form of	Energy
Heat is measured in	Joules (J)
Unit of energy	Joule

🌡️ THERMOMETER

Type	Use	Range	Liquid
Clinical Thermometer	Body temperature	95°F - 108°F (35°C - 42°C)	Mercury/Alcohol
Laboratory Thermometer	Experiments	-10°C to 110°C	Mercury/Alcohol

🌡️ TEMPERATURE SCALES

Scale	Freezing Point	Boiling Point	Divisions
Celsius	0°C	100°C	100
Fahrenheit	32°F	212°F	180

📝 CHAPTER 6 - IMPORTANT MCQs

Heat kya hai? → Form of energy
Heat energy measured in? → Joules
Unit of energy? → Joule
Temperature measure karne ke kitne scales hain? → Two (Celsius, Fahrenheit)
Degrees of hotness measure kaise karte hain? → Thermometer se
Laboratory thermometer mein lowest temperature? → -10°C
Laboratory thermometer mein highest temperature? → 110°C
Clinical thermometer mein kaunsa liquid use hota hai? → Mercury ya Alcohol
Water ka freezing point? → 32°F & 0°C
Water ka boiling point? → 212°F & 100°C
Fahrenheit mein kitne divisions hain? → 180
Celsius mein kitne divisions hain? → 100
Clinical thermometer Fahrenheit par kahan se kahan tak marked hai? → 95°F to 108°F
Normal body temperature? → 98.6°F (37°C)
Kink kya karta hai? → Mercury ko wapas girne se rokta hai

📖 CHAPTER 7: FORCE AND MACHINE

Aspect	Details
Force	Push (dhakelna) ya Pull (khinchana)
Speed	Kilometers per hour (km/h) mein measure karte hain
Effect of Force	Speed change kar sakta hai, direction change kar sakta hai

📝 CHAPTER 7 - IMPORTANT MCQs

Push ya pull ko kya kehte hain? → Force
Speed change kaise hoti hai? → Force se
Speed measure kaise karte hain? → Kilometers per hour (km/h) mein

📖 CHAPTER 8: SOUND

🔊 SOUND PRODUCTION

        VIBRATION → SOUND
           │
    Guitar ke taar vibrate
    Vocal cords vibrate
    Drum membrane vibrate

Sound vibration se banta hai

Aspect	Details
Sound is produced by	Vibrating objects
Sound cannot travel through	Vacuum
Snakes	No ears, feel vibrations through tongue
Sound travels fastest in	Solids
Unit of intensity	Decibels (dB)
WHO safe limit	75 dB
>115 dB	Noise

📝 CHAPTER 8 - IMPORTANT MCQs

Sound kaise produce hota hai? → Vibrating objects se
Sound kahan travel nahi kar sakta? → Vacuum mein
Snakes ke ears hote hain? → Nahi
Snakes vibrations kaise feel karte hain? → Tongue se
Sound kis terms mein describe karte hain? → Intensity (decibels)
Sound fastest kahan travel karta hai? → Solids mein
Decibel ka unit? → dB
WHO ke according safe dB? → 75 dB
115 dB se upar kya kehlata hai? → Noise

📖 CHAPTER 9: ELECTRICITY AND MAGNETISM

⚛️ ATOMS

ATOM STRUCTURE

            NUCLEUS
        ┌─────────────────┐
        │  PROTON (+)     │
        │  NEUTRON (0)    │
        └─────────────────┘
                │
        ELECTRONS (-) orbiting
            ⬤  ⬤  ⬤

Atom: Proton (+), Neutron (0), Electron (-)

Particle	Charge	Location
Electron	Negative (-)	Shells around nucleus
Proton	Positive (+)	Nucleus
Neutron	Neutral (0)	Nucleus

⚡ ELECTRICITY

Term	Definition
Current	Flow of electricity / Flow of electrons
Conductors	Materials through which electricity can pass (Metals)
Insulators	Materials through which electricity cannot pass (Plastic, Rubber)
Circuit	Path through which current passes
Open Circuit	Path mein break - Bulb OFF
Closed Circuit	Complete path - Bulb ON

🧲 MAGNETISM

MAGNET POLES

        NORTH (N) ──────── SOUTH (S)
           │                    │
        Opposite poles ATTRACT (N-S)
        Same poles REPEL (N-N, S-S)

Magnet ke do poles: North aur South

Aspect	Details
Magnet poles	Two (North and South)
Types of magnets	Two (Natural and Artificial)
Natural magnets	Permanent magnets (Lodestone)
Artificial magnets	Temporary magnets (Electromagnets)
Magnetic pole	End of magnet
Magnetism	Property to attract things

📝 CHAPTER 9 - IMPORTANT MCQs

Flow of electricity ko kya kehte hain? → Current
Conductors kya hain? → Jinme se electricity pass ho
Insulators kya hain? → Jinme se electricity pass na ho
Circuit kya hai? → Path through which current passes
Matter kis se bana hai? → Atoms se
Atom ke fundamental particles? → Electron, Proton, Neutron
Kaunsa particle negatively charged? → Electron
Kaunsa particle positively charged? → Proton
Kaunsa particle neutral? → Neutron
Circuits kitne types ke hote hain? → Two (Open and Closed)
Magnet ke kitne poles hote hain? → Two (North and South)
Magnets kitne types ke hote hain? → Two (Natural and Artificial)
Electricity se bane magnets? → Electromagnets
Natural magnets ko aur kya kehte hain? → Permanent magnets
Artificial magnets ko aur kya kehte hain? → Temporary magnets
Magnet ke end ko kya kehte hain? → Magnetic pole
Magnetism kya hai? → Attract karne ki property
Opposite poles? → Attract
Same poles? → Repel
Electromagnet kaise banta hai? → Electricity se

📖 CHAPTER 10: MOVEMENTS OF THE EARTH

🌍 EARTH'S MOVEMENTS

        ROTATION                    REVOLUTION
    Earth apni axis par         Earth Sun ke around
        24 hours                     365 days
           │                            │
    Day and Night                  Seasons

Rotation (24 hrs) → Day/Night, Revolution (365 days) → Seasons

Movement	Definition	Time	Result
Rotation	Earth ka apni axis par ghoomna	24 hours	Day and Night
Revolution	Earth ka Sun ke around ghoomna	365.25 days	Seasons

📐 TILT OF EARTH

Earth is tilted at an angle of: 23.5 degrees

Importance: Tilt hi seasons ka reason hai!

Agar tilt na hota: Koi seasons nahi hote, poles pe hamesha cold, equator pe hamesha hot

📝 CHAPTER 10 - IMPORTANT MCQs

Earth rotates from? → West to East
Earth ke rotation ko kya kehte hain? → Axial rotation
Rotation se kya hota hai? → Day and Night
Earth ka Sun ke around ghoomna? → Revolution
Revolution se kya hota hai? → Summer and Winter (Seasons)
Earth kitne degrees tilted hai? → 23.5 degrees
Rotation ka time? → 24 hours (1 day)
Revolution ka time? → 365.25 days (1 year)
Leap year kyun aata hai? → Extra 0.25 day har saal, 4 saal mein 1 day
Summer Solstice kab hota hai? → June 21
Winter Solstice kab hota hai? → December 21
Spring Equinox kab hota hai? → March 21
Autumn Equinox kab hota hai? → September 23
Equinox mein kya hota hai? → Day = Night
Solstice mein kya hota hai? → Longest or shortest day

📝 QUICK REVISION - ALL CHAPTERS

Chapter	Key Points
Chapter 1: Our Body	Brain = Control system \| Digestion starts from Mouth \| Small intestine = 6-7m \| Lungs in chest cavity \| Heart beats 72/min \| Bones = 206 \| Skin = 2mm \| Teeth: 20 milk, 32 permanent
Chapter 2: Living Things	7 characteristics \| Butterfly: Egg → Larva → Pupa → Adult \| Frog: Spawn → Tadpole → Froglet → Frog \| Traits from parents
Chapter 3: Food & Health	Carbs = Quick energy \| Proteins = Building blocks \| Vitamins = Protection \| A→Night blindness, B→Beriberi, C→Scurvy, D→Rickets \| Iron→Anemia \| Marasmus vs Kwashiorkor
Chapter 4: Food Chain	Producers → Primary → Secondary → Tertiary → Decomposers \| Herbivores, Carnivores, Omnivores \| 10% energy rule
Chapter 5: Matter	3 states: Solid, Liquid, Gas \| Heating: Solid→Liquid→Gas \| Cooling: Gas→Liquid→Solid \| Water = H₂O
Chapter 6: Heat	Heat = Energy (Joules) \| Thermometer \| Celsius: 0°C-100°C \| Fahrenheit: 32°F-212°F \| Clinical: 95°F-108°F
Chapter 7: Force	Force = Push or Pull \| Speed in km/h \| Force changes speed
Chapter 8: Sound	Sound = Vibration \| No sound in vacuum \| Snakes hear through tongue \| Safe limit = 75 dB \| >115 dB = Noise
Chapter 9: Electricity & Magnetism	Atom: Electron(-), Proton(+), Neutron(0) \| Conductors vs Insulators \| Open vs Closed circuit \| Magnet: 2 poles (N,S) \| Natural/Permanent vs Artificial/Temporary
Chapter 10: Earth Movements	Rotation (24 hrs) → Day/Night \| Revolution (365 days) → Seasons \| Tilt = 23.5°

Science class 4 | complete notes | 10 chapters