Energy

    AQA
    GCSE

    This topic establishes the fundamental principle of the Conservation of Energy, stating that energy cannot be created or destroyed, only transferred between different stores. Students analyze various energy stores, including kinetic, gravitational potential, elastic potential, and thermal, quantifying these changes through specific mathematical relationships. The concepts of work done, power as the rate of energy transfer, and the efficiency of systems are explored to understand energy dissipation and waste. Furthermore, the topic evaluates global energy resources, comparing renewable and non-renewable sources based on reliability, environmental impact, and political implications.

    4
    Objectives
    3
    Exam Tips
    4
    Pitfalls
    5
    Key Terms
    4
    Mark Points

    Learning Objectives

    What you need to know and understand

    • Energy stores and systems: Kinetic, elastic potential, and gravitational potential energy.
    • Power: Rate of energy transfer or work done.
    • Energy transfers: Useful vs dissipated energy; efficiency.
    • Efficiency: Calculating useful energy/power output.

    Marking Points

    Key points examiners look for in your answers

    • Reference to 'energy stores' (e.g., thermal, kinetic) rather than vague terms like 'heat' or 'movement energy' is essential for credit.
    • In calculation questions, one mark is explicitly awarded for the correct substitution of values into the equation before any rearrangement is attempted.
    • For 'describe' questions regarding energy changes, marks are awarded for identifying the starting store, the transfer mechanism, and the final store.
    • Units must be correct for the final answer mark (e.g., Joules for energy, Watts for power, Seconds for time).

    Examiner Tips

    Expert advice for maximising your marks

    • 💡Always write down the equation you are using first, then substitute the numbers exactly as they appear in the question before rearranging to secure method marks.
    • 💡Memorize the specific units required: Mass in kg (not g), Distance/Height in m (not km), Time in s.
    • 💡When describing energy resources, avoid generic pros/cons; focus on specific factors like reliability (base load), start-up times, and specific environmental impacts (e.g., CO2 vs visual pollution).

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Using the term 'heat energy' instead of 'thermal energy store' or 'heating' (as a transfer method), which is penalized in high-tariff questions.
    • Forgetting to square the velocity ($v^2$) when calculating Kinetic Energy, leading to incorrect numerical answers.
    • Failing to convert time into seconds (from minutes or hours) when calculating Power ($P = E/t$).
    • Confusing 'Work Done' with 'Power'; Work Done is simply energy transferred (Joules), while Power is the rate of transfer (Watts).

    Study Guide Available

    Comprehensive revision notes & examples

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    Key Terminology

    Essential terms to know

    Likely Command Words

    How questions on this topic are typically asked

    Calculate
    Describe
    Explain
    Compare
    Suggest

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