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3.1.7
Water
Analytical deep dive — question counts, mark distribution, mastery curves, command-word breakdowns, and examiner narrative analysis.
Questions
1
Total marks
5
Marks / Q
5.0
Accessibility
65.0%
Mastery
20.0%
Student strength
25.0%
01
At a glance
3.1.7 · Water
8YRSYNTHESIS
3.1.7 (Water) appeared in 1 of the 8 years between 2017 and 2024, contributing 1 questions and 5 marks across Papers 1, 2 and 3. KNOWLEDGE dominates the mark distribution at 100.0% of total marks. The accessibility–mastery gap sits at 45.0 percentage points (65.0% vs 20.0%) — most students reach partial credit, but full marks remain harder to secure. The largest single question observed is worth 5 marks, signalling that AQA expects complete hierarchical accounts in this sub-section.
Access–mastery gap
+45 pp
Lowest mastery
2019 · 20.0%
Highest mastery
2019 · 20.0%
02
Question type split
By marks · compound to dominant
5MARKS
5
marks
Knowledge100.0%5 marks
Application0.0%0 marks
Calculation0.0%0 marks
(by marks; compound rows assigned to dominant type):
03
Credit terms — quick reference
Mark scheme tier-locked
1TERMS
Tier 1 · Always credit
Tier 2 · Sometimes credit
Reject · Never credit
transpiration (alone — without specifying stream); water as solute
04
Question patterns
Recurring formats & tariff structure
0PARAGRAPHS
05
Year-over-year presence
P1 + P3 · 2017–2024
8YEARS
| Year | Questions | Total marks | Mean accessibility | Mean mastery |
|---|---|---|---|---|
| 2017 | 0 | 0 | — COVID | — COVID |
| 2018 | 0 | 0 | — COVID | — COVID |
| 2019 | 1 | 5 | 65.0% | 20.0% |
| 2020 | 0 | 0 | — COVID | — COVID |
| 2021 | 0 | 0 | — COVID | — COVID |
| 2022 | 0 | 0 | — COVID | — COVID |
| 2023 | 0 | 0 | — COVID | — COVID |
| 2024 | 0 | 0 | — COVID | — COVID |
06
Mark scheme intelligence
2017–2024 mark scheme corpus
1TERMS
Tier 1 — frequently credited
| Term | Times credited | Years | Notes |
|---|---|---|---|
| transpiration (alone — without specifying stream); water as solute | 1 | 2019 |
Marks in this sub-section are typically awarded for precise terminology and correct application of biological principles. Sequential mark schemes — where each mark requires building on the previous one — are common in multi-mark questions; stating the first step without progression rarely earns more than one mark. Calculation marks are typically split between method (correct setup and value extraction) and answer (accurate numerical result), allowing partial credit when arithmetic errors occur.
07
Where students lose marks
Examiner-anchored error patterns
1CASE STUDIES
Conceptual errors
- Water described as a solute rather than a solvent — a significant number of students made this fundamental inversion; water is the dissolving medium in biological systems, not a dissolved substance (2019 P1 Q10.1)
- Heat capacity and latent heat of vaporisation confused — these are distinct properties with different biological consequences: high heat capacity resists temperature change, large latent heat of vaporisation provides cooling through evaporation; the examiner noted they were frequently conflated or accompanied by incomplete explanations (2019 P1 Q10.1)
- Water as a metabolite not recognised — very few students identified water as a reactant and product in metabolic reactions such as condensation and hydrolysis; this mark point was consistently missed despite being a direct specification requirement (2019 P1 Q10.1)
Vocabulary errors
- "Aids transpiration" written for cohesion without specifying the transpiration stream — cohesion's contribution must be described as maintaining the transpiration stream, the column of water pulled up the xylem; "aids transpiration" alone was not credited (2019 P1 Q10.1)
- Limited examiner data available for this category beyond the above.
Application errors
- Property stated without its biological importance — the question required explaining why each property matters to organisms; many students named the property without completing the explanation; both the property and its biological significance are required for each mark point (2019 P1 Q10.1)
- Limited examiner data available for this category beyond the above.
High-impact failures · examiner narrative
2019 P1 Q10.15 marks20%full marks
Tested five properties of water important to organisms. Only 20% scored full marks. The question required a paired structure for each mark: property stated plus biological importance explained — and many students demonstrated only one of the two. Water as a metabolite was the mark point missed most comprehensively: "very few" cited it despite its presence in the specification. The solvent/solute inversion affected a measurable proportion of answers. Heat capacity and latent heat were conflated repeatedly. Cohesion responses typically included the word "transpiration" but did not specify the transpiration stream, failing to earn the mark. The question illustrates how 65% accessibility masks a 45-percentage-point gap to full marks: most students could name some properties, but the paired explanation format consistently undid partial-credit attempts.
08
Difficulty signals
Performance metric synthesis
45PP GAP
Mean accessibility
65.0%
Mean mastery
20.0%
Mean student strength
25.0%
The accessibility–mastery gap of 45.0 percentage points characterises this sub-section's difficulty profile. Most students reach partial credit; full marks remain harder to achieve. Within 3.1 (Biological molecules), 3.1.7 ranks 1 of 7 sub-sections by mean mastery (1 = hardest). Mean mastery was lowest in 2019 (20.0%) and highest in 2019 (20.0%).