Biology Extended Essay Exemplar: Potassium Nitrate and Phaseolus… | RevisionDojo

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IB Biology HL Extended Essay Example

How do varying concentrations of potassium nitrate (KNO3) (0.0 g/dm-3 (control), 25.0 g/dm-3,75.0 g/dm-3, 125.0 g/dm-3, 175.0 g/dm-3, and 225.0 g/dm-3(±0.5 g/dm-3) affect the stem heights of Phaseolus vulgaris (bean plants), measured in mm (±0.05 mm) in a span of 14 days?HL

Official IB Result

IB Grade: B

Criteria A: Focus and Method

4/6

Criteria StrandsPro

A.1Topic communication and explanation

Moderate

A.2Research question formulation and focus

Moderate

A.3Methodology appropriateness and completeness

Poor

Criteria Feedback

The student identifies a clear biological topic and keeps the investigation centered on the effect of potassium nitrate on bean stem growth.
The student shows awareness of an appropriate experimental setup by including a control, a range of treatments, and replicates.
The student explains why the investigation matters in a broader agricultural context.

The background becomes too broad in places and includes material that does not directly support the investigation.
Some biological explanations are imprecise or not fully aligned with the actual fertilizer used.
The treatment concentrations and method details are not consistently defined across the report.

Criteria B: Knowledge and Understanding

4/6

Criteria StrandsPro

B.1Application of source material

Moderate

B.2Use of terminology and concepts

Moderate

Criteria Feedback

The student uses a range of relevant sources to build a biological rationale for the study.
The student applies terminology such as nitrate, potassium ions, osmotic potential, turgor pressure, and mitosis with reasonable familiarity.
The student generally shows that they understand how mineral nutrition can influence plant growth.

Some sources are summarized rather than used critically to shape the investigation.
A few claims are not clearly linked to evidence or are biologically inaccurate.
Units and scientific notation are not always used consistently.

Criteria C: Critical Thinking

8/12

Criteria StrandsPro

C.1Research analysis

Poor

C.2Discussion and evaluation

Poor

C.3Argument development

Poor

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: Presentation

3/4

Criteria StrandsPro

D.1Structure appropriateness

Moderate

D.2Layout and formatting

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.

Loading scores...

Official IB Result

IB Grade: B

Criteria A: Focus and Method

4/6

Criteria StrandsPro

A.1Topic communication and explanation

Moderate

A.2Research question formulation and focus

Moderate

A.3Methodology appropriateness and completeness

Poor

Criteria Feedback

The student identifies a clear biological topic and keeps the investigation centered on the effect of potassium nitrate on bean stem growth.
The student shows awareness of an appropriate experimental setup by including a control, a range of treatments, and replicates.
The student explains why the investigation matters in a broader agricultural context.

The background becomes too broad in places and includes material that does not directly support the investigation.
Some biological explanations are imprecise or not fully aligned with the actual fertilizer used.
The treatment concentrations and method details are not consistently defined across the report.

Criteria B: Knowledge and Understanding

4/6

Criteria StrandsPro

B.1Application of source material

Moderate

B.2Use of terminology and concepts

Moderate

Criteria Feedback

The student uses a range of relevant sources to build a biological rationale for the study.
The student applies terminology such as nitrate, potassium ions, osmotic potential, turgor pressure, and mitosis with reasonable familiarity.
The student generally shows that they understand how mineral nutrition can influence plant growth.

Some sources are summarized rather than used critically to shape the investigation.
A few claims are not clearly linked to evidence or are biologically inaccurate.
Units and scientific notation are not always used consistently.

Criteria C: Critical Thinking

8/12

Criteria StrandsPro

C.1Research analysis

Poor

C.2Discussion and evaluation

Poor

C.3Argument development

Poor

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: Presentation

3/4

Criteria StrandsPro

D.1Structure appropriateness

Moderate

D.2Layout and formatting

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.