Overall Paper Assessment
The 2024 CCEA AS Unit 1 paper assesses The Earth’s Capacity to Support Human Activity across seven compulsory questions totalling 75 marks in 90 minutes. The paper maintains a solid standard of core knowledge testing alongside practical numerical applications and an extended evaluative essay.
Where the Marks Are Distributed
High-value areas in this series include Energy Storage (Question 7, 15 marks), Energy from the Sun (Question 4, 13 marks), and Energy from Biomass (Question 6, 12 marks). Together, these three units make up over 53% of the total marks available. Meanwhile, technical physics/engineering principles surrounding Wind Energy (10 marks) and Macrogeneration & CHP (9 marks) provide vital foundation marks.
Mathematical and Applied Calculations
Two distinct calculation tasks appear in this paper: calculating the rotor swept area for a wind turbine (\(A = \pi r^2\)) requiring diameter-to-radius conversion, and sizing a solar thermal collector array (calculating annual thermal demand percentage, required surface area, and rounding up discrete physical modules). Candidates who layout step-by-step working gain full method marks even if a minor arithmetic slip occurs.
Key Pitfalls and Mark Scheme Traps
- Air Density Misconceptions: In wind energy, explaining why colder nighttime air yields higher turbine power output than warmer midday air requires explicit reference to higher air density at lower temperatures.
- Rounding Module Counts: In solar thermal sizing calculations, fractional modules must be rounded up to the nearest whole integer to fully meet thermal load requirements.
- Energy Transformation Chains: When asked for energy changes in thermal/biomass power plants or pumped storage systems, generic answers fail; precise scientific energy forms (chemical \(\rightarrow\) thermal \(\rightarrow\) kinetic \(\rightarrow\) electrical) are strictly required.
- QWC Essay Structure: Question 7 demands coverage of all three bullet points (intermittency of renewables, mechanical/energy operation of pumped hydro storage, and topographical/grid site assessment criteria) to access Level 3 (11–15 marks).