Class 6 Science — Complete Notes with Diagrams

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Chapter 1: Food — Where Does it Come From?

Sources of Food

PLANT SOURCES:
  Roots:   Carrot, Radish, Beetroot, Turnip
  Stems:   Potato (underground stem), Sugarcane, Ginger
  Leaves:  Spinach, Cabbage, Lettuce, Curry leaves
  Fruits:  Mango, Banana, Apple, Orange, Tomato
  Seeds:   Wheat, Rice, Dal, Groundnut, Mustard
  Flowers: Cauliflower, Broccoli

ANIMAL SOURCES:
  Milk → Curd, Butter, Ghee, Cheese, Paneer
  Eggs → Hen, Duck, Ostrich eggs
  Meat → Chicken, Mutton, Fish, Prawns

EATING HABITS:
  Herbivores: Only plants (cow, horse, rabbit, deer)
  Carnivores: Only animals (lion, tiger, eagle, wolf)
  Omnivores:  Both plants and animals (human, crow, bear)

Components of Food (Nutrients)

NUTRIENT      SOURCE               FUNCTION           TEST
─────────────────────────────────────────────────────────────
Carbohydrates Rice, wheat, potato  Provides energy    Iodine→blue-black
Proteins      Dal, egg, milk, meat Growth & repair    Biuret→violet
Fats          Oil, butter, nuts    Energy storage     Paper grease test
Vitamins      Fruits, vegetables   Protect from       Various
                                   deficiency diseases
Minerals      Milk (Ca), Spinach   Bones, blood,      Various
              (Fe), Banana (K)     body functions
Water         Drinks, fruits       Transport, cooling  —
Roughage      Vegetables, fruits   Aids digestion,    —
(dietary      whole grains         prevents           
fiber)                             constipation

Deficiency Diseases

VITAMIN A  → Night blindness (cannot see in dim light)
            Sources: Carrot, papaya, milk, egg
            
VITAMIN B1 → Beriberi (nerve and heart problems)
(Thiamine)   Sources: Whole grains, nuts, legumes
             
VITAMIN B12→ Anaemia (fewer red blood cells)
             Sources: Meat, dairy, eggs
             
VITAMIN C  → Scurvy (bleeding gums, loose teeth)
(Ascorbic)   Sources: Amla, lemon, orange, guava
             
VITAMIN D  → Rickets (soft/bent bones in children)
             Sources: Sunlight, milk, fish liver oil

IRON       → Anaemia (tiredness, pale skin)
             Sources: Spinach, jaggery, meat

CALCIUM    → Weak bones, dental problems
             Sources: Milk, curd, ragi

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Chapter 2: Components of Food — Body Functions

Balanced Diet Diagram

FOOD PLATE (balanced diet):

    ┌─────────────────────────────────┐
    │          YOUR PLATE             │
    │  ┌─────────┬─────────────────┐  │
    │  │ GRAINS  │   VEGETABLES    │  │
    │  │ (roti,  │ (sabzi,salad)   │  │
    │  │ rice,   │   largest!      │  │
    │  │ pasta)  │                 │  │
    │  ├─────────┼─────────────────┤  │
    │  │ PROTEIN │ FRUITS          │  │
    │  │ (dal,   │ (apple,         │  │
    │  │ egg,    │ banana,         │  │
    │  │ chicken)│ mango)          │  │
    │  └─────────┴─────────────────┘  │
    │         🥛 DAIRY               │
    │         (milk/curd)             │
    └─────────────────────────────────┘

Half your plate: Fruits + Vegetables
Quarter: Grains (whole grains preferred)
Quarter: Protein
Small: Dairy

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Chapter 3: Fibre to Fabric

Natural vs Synthetic Fibres

NATURAL FIBRES (from plants or animals):

  COTTON (from cotton plant):
    Boll → Ginning (remove seeds) → Spinning → Weaving
    
    Cotton plant:
    🌿 Plant → 🌸 Flower → ☁ Boll (white fluffy mass)
    
    Properties: Soft, absorbs sweat, breathable, good for summer
    
  JUTE (from jute plant):
    Retting (soaking in water) → Separating fibres → Spinning → Weaving
    Properties: Rough, strong, biodegradable (eco-friendly)
    Uses: Gunny bags, ropes, floor mats

  WOOL (from sheep):
    Shearing → Scouring (washing) → Sorting → Spinning → Weaving
    
  SILK (from silkworm):
    Silkworm spins cocoon → Unwinding silk thread (sericulture)
    
SYNTHETIC FIBRES (man-made from chemicals):
  Nylon, Polyester, Acrylic, Rayon (semi-synthetic)

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Chapter 4: Sorting Materials into Groups

Properties of Materials

PHYSICAL PROPERTIES:

  LUSTRE (shiny/dull):
    Shiny: Gold, Silver, Copper, Iron (metals)
    Dull: Wood, Paper, Cotton, Rubber
    
  HARDNESS:
    Hard: Diamond (hardest), Iron, Glass, Stone
    Soft: Cotton, Rubber, Wax, Sponge
    
  SOLUBILITY in water:
    Soluble: Salt, Sugar, Copper sulphate
    Insoluble: Sand, Chalk, Oil (oil doesn't dissolve)
    
  TRANSPARENCY:
    Transparent: Glass, Clear water, Air (you can see through)
    Translucent: Frosted glass, Butter paper (partial)
    Opaque: Wood, Metal, Stone (cannot see through)
    
  CONDUCTORS and INSULATORS:
    Conductors (allow electricity): Copper, Iron, Aluminium
    Insulators (block electricity): Rubber, Plastic, Wood, Glass

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Chapter 5: Changes Around Us

Reversible vs Irreversible Changes

REVERSIBLE CHANGES:
  Original substance can be recovered
  
  Ice ←→ Water ←→ Steam
  (melting)      (boiling)
  (freezing)     (condensing)
  
  More examples:
    Stretching a rubber band → release → back to normal
    Dissolving salt in water → evaporate water → get salt back
    Inflating a balloon → deflate → back to flat
    Folding paper → unfold → back to flat sheet
    
IRREVERSIBLE CHANGES:
  New substance formed, CANNOT go back
  
  Examples:
    Burning paper → ash (cannot become paper again)
    Cooking food → cooked (cannot become raw)
    Rusting iron → rust (very hard to reverse)
    Curdling milk → curd (cannot become milk)
    Growing up → aging (cannot reverse)
    Cutting hair → cannot reattach

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Chapter 6: Body Movements

Types of Joints in Human Body

BALL AND SOCKET JOINT:
  Allows movement in ALL directions (360°)
  
    ┌─────┐
    │ Ball│ ← fits into socket
    │     ├──────────────────
    │     │ ← Socket (cup-shaped)
    └─────┘
    
  Found at: Shoulder, Hip
  Movement: Forward/backward, side/side, rotation

HINGE JOINT:
  Allows movement in ONE plane only (like door hinge)
  
    ──┬──          ← arm
      │  ← hinge
    ──┘
    
  Found at: Knee, Elbow, Fingers, Toes
  Movement: Bending and straightening only

PIVOT JOINT:
  Allows rotation (turning)
  Found at: Neck (Atlas and Axis bones)
  Movement: Rotate head left and right

FIXED JOINT (Immovable):
  No movement at all
  Found at: Skull bones (protect brain)

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Chapter 7: Light, Shadows and Reflections

Shadow Formation

SHADOW requires 3 things:
  1. A source of light (sun, torch, lamp)
  2. An opaque object (blocks light)
  3. A screen/surface (where shadow falls)

                    Torch
                      │
                      │ light rays
                      ▼
               ┌──────────┐
               │  Object  │ (opaque)
               └──────────┘
                      │
    ████████████████████████████ ← Screen/Wall
              Shadow
              (dark area where light is blocked)

Shadow size depends on:
  Object closer to light → BIGGER shadow
  Object farther from light → SMALLER shadow
  Light from above → SHORT shadow (noon)
  Light from side → LONG shadow (sunrise/sunset)

Rectilinear Propagation of Light

Light travels in STRAIGHT LINES:
  → That's why shadows have sharp edges
  → That's why you cannot see around corners
  → Explains solar and lunar eclipses

LUNAR ECLIPSE:
  Sun ──────── Earth ──────── Moon
  (Moon enters Earth's shadow)

SOLAR ECLIPSE:
  Sun ──── Moon ──── Earth
  (Moon blocks sun's light from Earth)

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Chapter 8: Electricity and Circuits

Electric Circuit Diagram

SIMPLE CIRCUIT:

  ┌──────────┬──────────┬──────────┐
  │          │          │          │
  +  Battery  -   Switch    Bulb 💡
  │          │          │          │
  └──────────┴──────────┴──────────┘

For current to flow:
  ✓ Battery (energy source)
  ✓ Complete closed path (no breaks)
  ✓ Switch closed (ON)
  ✓ Conducting wires

Open circuit: Switch OFF → bulb doesn't glow
Closed circuit: Switch ON → bulb glows

CONDUCTORS: Allow current (copper, iron, aluminium)
INSULATORS: Block current (plastic, rubber, glass, wood)

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Quick Revision — Class 6 Science

• [ ] 6 nutrients: Carbohydrates, Proteins, Fats, Vitamins, Minerals, Water
• [ ] Iodine test: starch → blue-black
• [ ] Vitamin C deficiency → Scurvy (bleeding gums)
• [ ] Vitamin D deficiency → Rickets (soft bones)
• [ ] Natural fibres: Cotton, Jute, Wool, Silk
• [ ] Reversible: ice↔water; Irreversible: burning, cooking
• [ ] Ball-and-socket (shoulder, hip): all directions
• [ ] Hinge joint (knee, elbow): one direction only
• [ ] Shadow needs: light source + opaque object + screen
• [ ] Light travels in straight lines
• [ ] Closed circuit: current flows; Open circuit: current stops
• [ ] Conductors: metals; Insulators: plastic, rubber, wood