Asteroids

    OCR
    GCSE

    Asteroids are minor planets, primarily rocky or metallic remnants from the early formation of the Solar System, distinct from volatile-rich comets. Most reside in the Main Asteroid Belt between Mars and Jupiter, orbiting the Sun due to gravitational attraction, though Near-Earth Objects (NEOs) pose potential impact risks. Understanding asteroids provides critical evidence regarding the accretion process of planetary formation and the history of bombardment in the inner Solar System.

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    Objectives
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    Exam Tips
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    Pitfalls
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    Key Terms
    5
    Mark Points

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Award 1 mark for stating that asteroids are primarily composed of rock and metal
    • Award 1 mark for identifying the main asteroid belt is located between the orbits of Mars and Jupiter
    • Award 1 mark for describing asteroids as leftover material/debris from the formation of the Solar System
    • Award 1 mark for distinguishing asteroids from comets based on composition (rock vs ice) or orbit (less elliptical than comets)
    • Credit responses that identify Ceres as a dwarf planet located within the asteroid belt

    Example Examiner Feedback

    Real feedback patterns examiners use when marking

    • "You correctly identified the composition, but check the location—remember the belt is after Mars, not Earth"
    • "Good comparison of orbits. To improve, explicitly mention the materials (ice vs rock) to explain the differences"
    • "You've stated they orbit the Sun, which is correct. Now explain why they didn't form into a planet (gravity of Jupiter)"
    • "Precise use of 'orbital period'. Ensure you distinguish between the asteroid belt and the Kuiper belt in your description"

    Marking Points

    Key points examiners look for in your answers

    • Award 1 mark for stating that asteroids are primarily composed of rock and metal
    • Award 1 mark for identifying the main asteroid belt is located between the orbits of Mars and Jupiter
    • Award 1 mark for describing asteroids as leftover material/debris from the formation of the Solar System
    • Award 1 mark for distinguishing asteroids from comets based on composition (rock vs ice) or orbit (less elliptical than comets)
    • Credit responses that identify Ceres as a dwarf planet located within the asteroid belt

    Examiner Tips

    Expert advice for maximising your marks

    • 💡When describing the structure of the Solar System, explicitly mention the 'asteroid belt between Mars and Jupiter' to secure specific AO1 marks
    • 💡In comparison questions, create a clear distinction: Asteroids = Rock/Metal, Comets = Ice/Dust
    • 💡If asked about the formation of the Solar System, cite asteroids as evidence of the accretion process that formed the planets

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Confusing asteroids with comets by suggesting asteroids have tails or highly elliptical orbits
    • Incorrectly placing the asteroid belt between Earth and Mars, or beyond Neptune (confusing with Kuiper Belt)
    • Describing asteroids as 'failed stars' rather than planetary debris or minor planets
    • Stating that asteroids orbit planets (confusing them with moons) rather than orbiting the Sun

    Study Guide Available

    Comprehensive revision notes & examples

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    Key Terminology

    Essential terms to know

    Solar System formation and accretion models
    Orbital mechanics and gravitational forces
    Classification of minor bodies (asteroids vs. comets vs. meteors)
    Impact hazards and kinetic energy transfers

    Likely Command Words

    How questions on this topic are typically asked

    State
    Describe
    Explain
    Compare
    Suggest

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