IB Biology SL Extended Essay Exemplar
HOW DO DIFFERENT CONCENTRATION OF MICROPLASTIC (20 mg/L, 40 mg/L, 60 mg/L, 80 mg/L, 100 mg/L) IN WATER AFFECT GROWTH RATE OF Hydrilla ver cillata BY MEASURING THE CHANGES IN LENGTH AND TOTAL CHLOROPHYLL CONTENT AFTER 7 DAYS
B
Overall Score
21/28
IB Grade: B
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21/28
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14
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6.1·question
Page 28
Appendix materials are clearly presented but should not receive feedback annotations, as per guidelines.
Criteria A: Focus and Method
6/6
0
3
6
Criteria Strands
Excellent
Topic communication and explanation
Excellent
Research question formulation and focus
Good
Methodology appropriateness and completeness
Criteria Feedback
- Introduction clearly situates the problem, defines key concepts, and links to the organism with comprehensive explanation.
- Research question is explicitly stated, narrowly focused, and addresses a pertinent environmental biology issue.
- Methodology steps are clearly enumerated and controlled variables are comprehensively tabulated.
- Source of microplastics lacks particle-size assessment, limiting ecological relevance.
- Environmental conditions (light intensity, temperature) are only partly controlled or reported.
Criteria B: Knowledge and Understanding
5/6
0
3
6
Criteria Strands
Good
Application of source material
Excellent
Use of terminology and concepts
Criteria Feedback
- Accurate and consistent use of scientific terminology (e.g., absorbance, Pearson correlation, RuBisCO).
- Correct application of statistical formulas (degrees of freedom, chlorophyll calculations) demonstrates mathematical precision.
- Engagement with background literature is sometimes descriptive rather than integrative, limiting the depth of contextualization.
- Interpretation of results relies heavily on the student's own data, with limited triangulation from external sources.
Criteria C: Critical Thinking
6/12
0
6
12
Criteria Strands
Moderate
Research analysis
Poor
Discussion and evaluation
Poor
Argument development
Criteria Feedback
- Data analysis is logically connected to the research question, with correct calculation of growth rates, chlorophyll content, error bars, and Pearson correlation.
- Graphical interpretation (R², critical r value) is precise and clearly linked to hypothesis testing.
- Safety and ethical considerations are comprehensively addressed.
- Evaluation of limitations is general; suggestions for improving validity could be more specifically linked to particular methodological gaps.
- Argument contains minor inconsistencies (mis-labelling, occasional text/graph discrepancies).
Criteria D: Presentation
4/4
0
2
4
Criteria Strands
Excellent
Structure appropriateness
Good
Layout and formatting
Criteria Feedback
- Report follows all prescribed sections in logical order, with clear sub-headings, numbered tables, and figures throughout.
- Word count, title page, page numbers, and table/figure captions are consistently provided, supporting reader navigation.
- Some typographical and formatting inconsistencies (misaligned tables, stray symbols) detract from full polish.
- Inconsistent citation formatting and missing units in one table reduce clarity marginally.