Complete revision

• Types of energy

  • Kinetic
  • Potential
  • Thermal
  • Electrical
  • Light
• Real-world examples of energy types

  • Moving car
  • Stretched rubber band
  • Hot cup of coffee
  • Light bulb
  • The sun
• Energy transformations

  Electrical energy to light and heat energy
• Electrical energy

  Used in lighting, heating, and transportation
• Static electricity

  Charging of objects and observation of electrostatic interactions
• Conductors

  Allow the flow of electrons
• Insulators

  Do not allow the flow of electrons
• Voltage

  Electrical potential difference (V) between two points in a circuit
• Current

  Rate of flow of electric charge, measured in amperes (A)
• Resistance

  Measure of opposition to the flow of electric current, with the unit of ohms (Ω)
• Ohm's Law

  Relationship between voltage, current, and resistance as V = IR
• Circuit diagrams and symbols

  Represent the components and connections in real-world electrical circuits
• Wind turbine

  Converts the kinetic energy of wind into electrical energy
• Wind turbine design factors

  • Blade length
  • Rotor diameter
  • Tower height
• Wind turbine performance data

  Presented through graphs and tables
• Patterns and trends observed in the data can provide insights into the factors affecting wind turbine efficiency
• Plausible explanations or interpretations of the data can be derived to understand the principles of wind turbine design
• Ecosystem

  A community of living organisms and their physical environment, where energy and matter flow through the system
• Energy flow in an ecosystem

  1. Photosynthesis by producers

  2. Transfer through food chain

  3. Food web
• Cellular respiration and photosynthesis

  Key processes governing the flow of energy in an ecosystem
• Ecological relationships

  • Predator-prey
  • Competition
  • Symbiosis
  • Parasitism
  • Mutualism
  • Commensalism
• Subatomic particles

  Protons, neutrons, and electrons, with distinct locations, charges, and relative masses
• Periodic table

  Organizes elements based on their atomic number and relative atomic mass
• Rutherford-Bohr model

  Describes the arrangement of electrons in the shells of an atom
• Ions

  Atoms that have gained or lost electrons, forming either cations or anions
• Atomic trends

  • Atomic radii
  • Electronegativity
  • First ionization energy
• Octet rule

  Tendency of atoms to form stable configurations by gaining, losing, or sharing electrons
• Ionic bonds

  Form when atoms transfer electrons
• Covalent bonds

  Involve the sharing of electrons
• Bond polarity

  Determined by the electronegativity difference between the bonded atoms
• Chemical reactions

  Involve the rearrangement of atoms to form new substances, driven by the goal of achieving stability
• Factors influencing reaction rates

  • Temperature
  • Pressure
  • Surface area
  • Presence of catalysts
• First law of thermodynamics

  Energy can be converted from one form to another but cannot be created or destroyed
• Second law of thermodynamics

  Systems tend to move towards a state of greater disorder or entropy
• Energy transformations

  Follow the principles of energy conservation and entropy
• Energy conversion efficiency

  Ratio of useful output to total energy input
• Renewable energy sources

  Sustainable alternatives to non-renewable fossil fuels
• Ecosystem services

  Food production, water purification, and climate regulation
• Biodiversity

  Variety of living organisms in an ecosystem, crucial for maintaining ecosystem stability and resilience
• Human activities

  Negative impacts on ecosystems (habitat destruction, pollution, resource overexploitation)