Unit 1: Elements, Compounds and Mixtures

Substances: Pure and Impure

  • Pure substance: Contains only one type of particle (element or compound)
  • Impure substance: Contains more than one type of particle (mixture)

Atoms

  • Subatomic particles: Protons, Neutrons, Electrons
  • Properties:
    • Proton: +1 charge, mass ≈ 1 u, in nucleus
    • Neutron: 0 charge, mass ≈ 1 u, in nucleus
    • Electron: -1 charge, negligible mass, in electron cloud
  • Difference between atom and ion:
    • Atom: Neutral, equal protons and electrons
    • Ion: Charged, gained or lost electrons

Elements

  • Writing symbols: e.g., H, O, Na, Cl
  • Atomic number: Number of protons in the nucleus
  • Mass number: Total number of protons + neutrons

Periodic Table

  • Groups: Vertical columns; elements with similar properties
  • Periods: Horizontal rows; properties change gradually
  • Arrangement: By increasing atomic number

Compounds

  • Valency: Combining capacity of an element
  • Naming compounds:
    • Metal + Non-metal (M-NM): e.g., NaCl
    • Non-metal + Non-metal (NM-NM): e.g., CO2
    • Oxides, Hydroxides, Sulphates, Carbonates: Follow standard rules
  • Chemical reactions: Writing word equations (e.g., H2 + O2 → H2O)

Mixtures

  • Separating mixtures:
    • Evaporation
    • Distillation
    • Fractional distillation
    • Chromatography

Introduction to Acids and Alkalis

  • Properties of acids: Sour taste, turns blue litmus red, pH < 7
  • Properties of alkalis: Bitter taste, turns red litmus blue, pH > 7
  • pH scale and indicators: Measure acidity or alkalinity
  • Neutralisation: Acid + Alkali → Salt + Water
Exam Tip: Memorise the properties of acids, alkalis, and the method for naming compounds. Practice drawing the periodic table layout and identifying groups and periods.

Unit 2: Human Impact on the Environment

Biodiversity, Food Chain & Food Web

  • Biodiversity: Variety of life in an ecosystem
  • Food chain: Linear sequence showing energy transfer from one organism to another
  • Food web: Interconnected food chains showing complex feeding relationships

Energy Flow & Trophic Levels

  • Energy flows from the Sun → Producers → Consumers → Decomposers
  • Trophic levels:
    • Producers: Make their own food via photosynthesis (e.g., plants)
    • Consumers: Eat other organisms (herbivores, carnivores, omnivores)
    • Decomposers: Break down dead organisms, recycle nutrients (e.g., bacteria, fungi)

Ecological Pyramids

  • Types of pyramids:
    • Number: Number of organisms at each trophic level
    • Biomass: Mass of living material at each level
    • Energy: Energy available at each trophic level
  • Energy decreases as you move up the trophic levels (10% rule)

Management of Natural Resources

  • Importance of conserving resources to maintain ecological balance
  • Examples: Afforestation, water conservation, sustainable agriculture

Human Activities Impact on Environment

  • Overpopulation, industrialisation, urbanisation, deforestation
  • Pollution types:
    • Air pollution
    • Water pollution
    • Land pollution
  • Causes and effects:
    • Air: Acid rain, living indicators of air quality
    • Water: Eutrophication, bioaccumulation, biomagnification
    • Land: Deforestation, global warming, carbon footprint

Solutions

  • Saving forests and planting trees
  • Reducing pollution by sustainable practices
  • Promoting renewable energy and recycling
Exam Tip: Draw clear food chains and pyramids. Remember the effects of human activities on air, water, and land. Link solutions to each type of pollution.

Unit 3: Light and Sound

Waves

  • Types of waves: Longitudinal and Transverse
  • Properties:
    • Wavelength: Distance between two consecutive crests/troughs
    • Frequency: Number of waves per second
    • Amplitude: Maximum displacement of wave
    • Crest: Highest point of a wave
    • Trough: Lowest point of a wave

Classification of Waves

  • Mechanical waves: Require a medium to travel (e.g., sound)
  • Electromagnetic waves: Do not require a medium (e.g., light, radio)

Sound

  • Making sound waves: Vibrations in a medium
  • Speed of sound depends on medium (fastest in solids)
  • Detecting sound:
    • Amplitude → Loudness
    • Frequency → Pitch (example: musical instruments)
  • Types of sound waves:
    • Ultrasound: Above human hearing (>20 kHz)
    • Infrasound: Below human hearing (<20 Hz)

Human Ear

  • Structure: Outer ear, Middle ear, Inner ear
  • Hearing loss: Causes include damage to eardrum, loud sounds, age

Applications of Sound

  • Microphones and loudspeakers
  • Echoes: Reducing echoes in buildings
  • Sonar and animal echolocation
  • Ultrasound for medical imaging and detection

Light

  • Sources of light:
    • Luminous: Produce own light (Sun, bulb)
    • Non-luminous: Do not produce own light, visible via reflection (moon, moonlight)
  • Electromagnetic waves: Travel in vacuum; EM spectrum and applications
  • Properties of light:
    • Reflection: Bouncing back of light
    • Refraction: Bending of light at boundary
    • Dispersion: Splitting of light into colors (prism)

Reflection of Light

  • Types:
    • Regular: Smooth surfaces (mirror)
    • Irregular: Rough surfaces
  • Applications: Periscopes, kaleidoscopes

Refraction of Light

  • Refractive index: Measure of bending of light in a medium
  • Critical angle & Total Internal Reflection (TIR)
  • Applications of TIR: Optical fibers, periscopes
  • Dispersion: Prism splits white light into rainbow colors
  • Formation of Rainbow
  • Structure of Eye and its function
  • Application of Lasers
Exam Tip: Draw diagrams of waves, human ear, light reflection and refraction. Practice labeling EM spectrum and TIR applications.

Unit 4: Tissues, Human Systems, and Balanced Diet

Tissues

  • Plant tissues:
    • Meristematic tissue: Actively dividing cells, growth regions
    • Permanent tissue: Differentiated cells performing specific functions
    • Xylem: Transports water and minerals
    • Phloem: Transports food (sugars)

Unit 4: Tissues, Body Systems, and Balanced Diet

Specialized Cells

  • Blood cell: Transports oxygen and nutrients
  • Root hair cell: Absorbs water and minerals from soil
  • Muscle cell: Contracts and relaxes to produce movement

Human Body Organization

  • Cells → Tissues → Organs → Organ Systems → Organism

Plant Tissues

  • Meristematic tissue: Actively dividing cells, growth regions
  • Permanent tissue: Differentiated cells performing specific functions
  • Xylem: Transports water and minerals
  • Phloem: Transports food (sugars)

Animal Tissues

  • Epithelial tissue: Covers body surfaces (skin)
  • Connective tissue: Supports and connects body parts
    • Adipose tissue: Stores fat
    • Blood: Transports nutrients and oxygen
    • Bone: Provides structural support
  • Muscular tissue: Heart and skeletal muscles, contracts to produce movement
  • Nervous tissue: Neurons transmit electrical impulses

Human Systems

  • Nervous system: Controls and coordinates body activities
  • Digestive system: Breaks down food with the help of enzymes
  • Circulatory system: Transports blood, nutrients, and oxygen

Balanced Diet

  • Nutrients:
    • Proteins, Carbohydrates, Fats
    • Vitamins and Minerals
    • Fibre
  • Malnutrition: Calculating food requirements for balanced diet
  • Deficiency diseases:
    • Kwashiorkor: Protein deficiency
    • Scurvy: Vitamin C deficiency
    • Rickets: Vitamin D deficiency
    • Beri-Beri: Vitamin B1 deficiency
  • Overeating: Obesity
  • Relation between diet and fitness
Exam Tip: Memorise tissue types, cell functions, major body systems, and deficiency diseases. Use diagrams to illustrate human body organization and nutrient flow.

Unit 5: Electricity and Magnetism

Electricity

  • Static electricity:
    • Charging and discharging
    • Conductors and insulators
    • Effects of static electricity, lightning and thunder
    • Reducing risks of static electricity
  • Electric circuits:
    • Components, symbols, and diagrams
    • Types of circuits: Series and parallel
    • Current: Measuring, current in series and parallel circuits
    • Voltage: Measuring, voltage in series and parallel circuits

Magnetism

  • Introduction to magnets and their properties: Attraction and Repulsion
  • Types of magnetic materials:
    • Ferromagnetic, Paramagnetic, Diamagnetic
  • Magnetising and demagnetising methods:
    • Single touch, double touch, electric
  • Magnetic fields:
    • Drawing magnetic field lines
    • Pattern of field lines
    • Earth's magnetic field
  • Types of magnets:
    • Permanent magnets
    • Electromagnets: Making, strength, applications (relays, electric bells, MRI)
Exam Tip: Draw clear circuit diagrams and magnetic field patterns. Remember differences between series and parallel circuits and real-life applications of electromagnets.