Biology IA Exemplar: How does caffeine concentration (0, 0.4, 0.6,… | RevisionDojo

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IB Biology SL Internal Assessment Example

How does caffeine concentration (0, 0.4, 0.6, 0.8, and 1.0g/cm³) affect the time (seconds) taken for a protease solution (0.8 U/g) to digest proteins in a gelatin sheet (0.5 g), as shown by the viscosity of the protease caffeine mixture solution?SL

Official IB Result

IB Grade: 7

Criteria A: Research Design

5/6

Criteria StrandsPro

A.1Research question context

Good

A.2Methodological considerations

Moderate

A.3Methodology description

Moderate

Criteria Feedback

The student framed the investigation around a focused, testable question with clear variables and a measurable outcome.
The student showed relevant biological understanding by linking the question to enzyme activity, protease inhibition, and published research.
The student included enough procedural detail that much of the investigation could be repeated.

The student repeatedly described the independent variable as caffeine concentration even though the method actually changed coffee powder mass.
Several important confounding variables were not controlled, including total volume, enzyme dilution, and pH.
Some methodological choices were not fully justified, especially the use of coffee powder instead of quantified caffeine and the control setup.

Criteria B: Data Analysis

4/6

Criteria StrandsPro

B.1Communication of data recording and processing

Good

B.2Consideration of uncertainties

Moderate

B.3Data processing quality

Moderate

Criteria Feedback

The student organized the raw data and processed values clearly, making it easy to follow the path from measurements to summary statistics.
The student calculated and presented useful statistics such as means, standard deviations, range-based uncertainty, and inferential tests.
The student displayed the main trend clearly with a graph and error bars.

Some labels and terms are inconsistent or imprecise, especially where uncertainty and units are concerned.
The student's statistical interpretation includes errors, such as confusing R² with correlation and misstating the p-value threshold.
The processing cannot support a claim about caffeine specifically because the investigation actually compares coffee powder treatments with unequal preparation conditions.

Criteria C: Conclusion

6/6

Criteria StrandsPro

C.1Conclusion relevance and consistency

Moderate

C.2Scientific context comparison

Moderate

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Criteria D: Evaluation

6/6

Criteria StrandsPro

D.1Methodological weaknesses

Good

D.2Improvements

Excellent

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Loading scores...

Official IB Result

IB Grade: 7

Criteria A: Research Design

5/6

Criteria StrandsPro

A.1Research question context

Good

A.2Methodological considerations

Moderate

A.3Methodology description

Moderate

Criteria Feedback

The student framed the investigation around a focused, testable question with clear variables and a measurable outcome.
The student showed relevant biological understanding by linking the question to enzyme activity, protease inhibition, and published research.
The student included enough procedural detail that much of the investigation could be repeated.

The student repeatedly described the independent variable as caffeine concentration even though the method actually changed coffee powder mass.
Several important confounding variables were not controlled, including total volume, enzyme dilution, and pH.
Some methodological choices were not fully justified, especially the use of coffee powder instead of quantified caffeine and the control setup.

Criteria B: Data Analysis

4/6

Criteria StrandsPro

B.1Communication of data recording and processing

Good

B.2Consideration of uncertainties

Moderate

B.3Data processing quality

Moderate

Criteria Feedback

The student organized the raw data and processed values clearly, making it easy to follow the path from measurements to summary statistics.
The student calculated and presented useful statistics such as means, standard deviations, range-based uncertainty, and inferential tests.
The student displayed the main trend clearly with a graph and error bars.

Some labels and terms are inconsistent or imprecise, especially where uncertainty and units are concerned.
The student's statistical interpretation includes errors, such as confusing R² with correlation and misstating the p-value threshold.
The processing cannot support a claim about caffeine specifically because the investigation actually compares coffee powder treatments with unequal preparation conditions.

Criteria C: Conclusion

6/6

Criteria StrandsPro

C.1Conclusion relevance and consistency

Moderate

C.2Scientific context comparison

Moderate

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Criteria D: Evaluation

6/6

Criteria StrandsPro

D.1Methodological weaknesses

Good

D.2Improvements

Excellent

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.