Research & Design (28 criteria)

Code	Criterion	AI	Justification
RD1	The research topic is an appropriate Chemistry level for the IB DP Chemistry and abides by the IB DP Guidance of “Asking questions worth answering": • that are not easily answered using an online search engine • that are not versions of previously written practical reports • for which answers are not found in their textbook • for which the answers are not self-evident from the syllabus.	1	The research question about how pH affects borax crystallization yield is not easily answered by online search, not in standard textbooks, and requires experimental investigation to determine the relationship
RD2	Aim is focused in its breadth, investigating at a single relationship.	1	The aim focuses on a single relationship between pH (via HCl volume) and mass of crystals produced, with temperature rise being measured to calculate the final DV
RD3	Aim wording is specific, so the reader knows exactly what the investigation is about.	0	The aim does not specify the pH range being tested (7.63-8.75) or the specific HCl volume range (5-13 mL), which are required for specificity
RD4	Sufficiently appropriate referenced science background affecting the Dependent Variable (DV) to allow understanding of the investigation.	1	Background provides detailed chemistry including the borax-HCl reaction equation, crystallization theory, supersaturation concepts, and nucleation processes with proper citations
RD5	Sufficiently appropriate referenced science background explaining how the Independent Variable (IV) will potentially cause changes in the measured Dependent Variable	1	The background explains how pH changes affect electrostatic interactions, nucleation rate, and conversion of tetraborate ions to boric acid, with cited reference (Link and Jerry, 2022)
RD6	Valid hypothesis is justified by logical scientific reasoning and the chemistry is accurate and testable by the method.	1	The hypothesis clearly states the expected negative trend (lower pH leads to increased crystal mass) and is justified by the chemistry of tetraborate to boric acid conversion
RD7	Quantitative 'Measurable' Independent Variable (IV) to be manipulated is stated and used consistently when referenced throughout the report.	0	The IV switches inconsistently between 'pH' and 'volume of HCl' throughout the report without maintaining consistent terminology
RD8	Quantitative Independent Variable (IV) to be manipulated has correct units stated.	1	The pH units are dimensionless which is correctly stated in the background section when defining pH as ranging from 0-14
RD9	Quantitative Independent Variable (IV) concept is correctly applied to this specific experiment.	1	The IV of pH manipulation via HCl addition is correctly applied to this crystallization experiment to study the borax-boric acid conversion
RD10	Quantitative Independent Variable (IV) choice of values is justified.	1	The report justifies using 2M HCl for precise pH adjustments and states specific volumes (5, 7, 9, 11, 13 mL) with 2 mL increments
RD11	Quantitative Independent Variable (IV) to be manipulated is increased sequentially by intervals of equal values. Any deviation from this format is jusitified.	0	While 2 mL intervals are used for HCl volume, the actual pH values achieved (8.75, 8.45, 8.14, 7.94, 7.63) are not equal intervals
RD12	Quantitative Dependent Variable (DV) to be measured is stated consistently when referenced throughout the report.	0	The DV is inconsistently referred to as 'mass of crystals', 'mass after crystallization', and 'volume lost after crystallization'
RD13	Quantitative Dependent Variable (DV) to be measured has correct units stated.	1	The DV units are correctly stated as grams (g) for the mass of crystals produced
RD14	Quantitative Dependent Variable (DV) is described and the chemistry is accurate.	1	The DV is accurately described as the mass of boric acid crystals formed through the borax-HCl reaction with correct chemistry
RD15	Quantitative Dependent Variable (DV) choice of measurements is justified and the chemistry is accurate.	1	The choice to measure crystal mass is justified as it directly indicates the extent of boric acid formation from the pH-dependent reaction
RD16	All Controlled Variables (CV) are identified in a table, with no obvious omissions.	1	All major controlled variables are identified in the table including borax mass, HCl molarity, flame intensity, and dish diameter
RD17	Stating in a Controlled Variables table (CV) relevant to this study, with a column identifying the 'Value Maintained'.	1	The CV table includes specific values maintained: 7.5g borax, 2M HCl, air hole completely open, 8.5cm dish diameter
RD18	Stating in a table Controlled Variables (CV) relevant to this study, with a column for the 'Potential Effects'.	1	The CV table explains potential effects with specific directions, e.g., inconsistent borax would affect solution concentration and uncertainty range
RD19	Stating in a table Controlled Variables (CV) relevant to this study, with a column for the 'Method of Control'.	1	Methods of control are specified for each CV: digital balance for mass, using only 2M HCl, ensuring air hole open, using same sized dishes
📷 RD20	Provide a labelled and assembled apparatus diagram that accurately allows measurement as described in the method. (chemix.org)	1	The apparatus diagram shows all equipment properly assembled for measurement - burette positioned above beaker for titration, pH meter in solution, balances positioned for weighing, oven for crystallization. All components are clearly labeled and positioned as they would be used in the actual experiment.
RD21	All Equipment, sizes, absolute uncertainties, and amounts required for the experiment are listed or stated in the Equipment List	0	Equipment list is missing key items used in the method: heatproof mat, stirring rod, and oven mentioned in steps 5, 6, and 12
RD22	Described the trial runs and giving details of initial problems specific to this experiment, justifying modifications when designing the methodology.	1	Trial runs describe specific problems encountered: beaker surface area issue leading to evaporating dish use, and sodium chloride taking too long leading to borax use
RD23	3rd person, past tense, step-by-step method to carry out the investigation.	1	The method is written in past tense third person ('was measured', 'was lit', 'was taken') in step-by-step bullet format
RD24	Method has sufficient procedural fine detail to ensure all variables are controlled and the user can reproduce exact data and conclusions.	0	Method lacks critical details: stirring duration/speed in step 6, oven temperature and crystallization time in step 12, cooling time before weighing
RD25	Experiment is planned to contain at least five changes to the independent variable and justification given if this was not possible.	1	The experiment uses 5 different pH values (8.75, 8.45, 8.14, 7.94, 7.63) achieved by 5 different HCl volumes as stated in the method
RD26	Health and Safety considerations of all reactants, products and conditions are recorded in a Risk Assessment table.	1	Risk assessment table comprehensively lists hazards (HCl, Bunsen burner, borax), associated risks, and control measures for each
RD27	Risk Assessment table contains explicitly referenced CLEAPPS Hazcard numbers, referenced for specific chemicals/ concentrations used.	0	While CLEAPSS is referenced in the bibliography, specific Hazcard numbers are not cited in the risk assessment table for HCl or borax
RD28	Risk Assessment table contains explicitly referenced CLEAPPS Hazcard numbers, referenced for specific disposal of materials used or produced.	0	The disposal methods in the table are generic ('pour down drain', 'regular trash') without specific CLEAPSS Hazcard disposal references

Analysis (41 criteria)

Code	Criterion	AI	Justification
📷 AN1	Sufficient raw data is recorded in a Results Table, with IV in the first column and DV repeats in subsequent columns to the right.	1	Raw data tables show IV (pH of Boric acid) in first column and DV repeats (Mass of crystal) in subsequent columns to the right across 5 trials, following the traditional format required.
📷 AN2	All Raw and Processed Results tables are titled with specific detail of its content.	0	Tables are labeled as 'Trial run 1', 'Trial run 2', etc. but lack specific descriptive titles indicating what the data represents. Should have titles like 'Table 1: Raw Data of Crystal Mass at Different pH Values'.
📷 AN3	Data table column headings include 'Measurable' units.	1	All data table column headings include appropriate units in brackets - 'Volume of HCl added (±0.05 ml)', 'Mass of crystal (±0.001 g)', 'pH (±0.01)', etc.
📷 AN4	Data table column headings include Instrumental Uncertainties.	1	Column headings include instrumental uncertainties for all measurable values - ±0.05 ml for burette, ±0.001 g for mass, ±0.01 for pH, ±0.1 ml for syringe.
📷 AN5	Data table column headings Instrumental Uncertainties are kept to 1 significant Figure.	1	All instrumental uncertainties are expressed to 1 significant figure - ±0.001 g, ±0.01, ±0.05 ml, ±0.1 ml.
📷 AN6	Data tables are formatted adequately, making it easy to read. Running the table over page breaks, very small font and very narrow column sizes are a few examples of poor formatting.	1	Tables are well-formatted with clear columns, readable font size, and do not run across page breaks. Data is easy to read and interpret.
AN7	All Instrumental Uncertainties from measuring devices are justified. (Analogue = Half the smallest readable digit, Digital = Smallest Readable digit, or explictly written on the measuring instrument).	1	The student correctly justifies all instrumental uncertainties: Mass balance ±0.0005g (digital), Burette ±0.05ml (half smallest readable digit for analogue), pH meter ±0.01 (digital), Syringe ±0.1ml (half of 0.2ml smallest division). All justifications follow the correct principles for digital vs analogue instruments.
📷 AN8	The Decimal Points of raw and processed data are consistent with Instrumental Uncertainties on measurements	1	Decimal places in data match instrumental uncertainties - pH recorded to 2 decimal places matching ±0.01, masses to 4 decimal places matching balance precision of ±0.0005 g.
AN9	Qualitative observations Before, During, and After are recorded that will assist with interpretation.	0	The student only provides observations during step 8 and after crystallization (step 13). No 'before' observations are recorded. The criteria explicitly requires observations for all three phases: Before, During, and After.
📷 AN10	Qualitative observations are backed up by photographic evidence of the experiment	1	Photographic evidence of experimental setup is provided, showing petri dishes with crystals on paper, supporting the qualitative observations about crystal formation.
AN11	Attempts are made to repeat measurements, until they are within the Instrumental Uncertainty limits set out by the apparatus.	1	The student explicitly states attempts were made to repeat measurements for both pH meter ('observe the number that appeared consistently over several attempts') and mass balance ('Repeated measurements (Step: 10 and 13) were taken'). The key requirement of 'attempts' is met.
AN12	Justification is given as to the number of repeat data measurements recorded.	1	The student justifies stopping at 5 repeats, stating it 'helped to minimize random errors, such as the mass of crystal and inconsistencies in volume of solution (Boric acid) in evaporating dishes.' This provides specific reasoning for the number of repeats chosen.
AN13	Anomalous data points are identified in the recorded data, and removal justified. [No stdv mathematical requirement].	0	The student states 'No anomalous data was collected' but does not identify or discuss any potential outliers. The criteria requires identification of anomalous points and justification for removal, not simply stating none exist.
AN14	If the experiment requires any processing through additional equations, then any necessary calculations in order to process data are complete and without errors. Mark to be awarded if no additional equations are necessary.	1	The student correctly identifies that no additional equations are needed (stated as 'No additional calculations needed'). The experiment directly measures mass of crystals as the DV, requiring no further processing equations.
AN15	The specific 'First' chosen change in IV Value is stated, for which the subsequent raw DV data will be used to calculate the Mean Average DV in a Worked Example Calculation.	0	The student states 'The raw data to be used to calculate the mean average will be the mass of the crystal' but does not specify which IV value (which pH value) will be used for the worked example. The criteria requires stating the specific 'first' IV value.
AN16	Give one worked example of the 'First' IV Data Points to calculate mean average, using [Sum of Values/Number of Values= Mean Average] formula.	0	No worked example is provided showing the calculation of mean average using the formula [Sum of Values/Number of Values = Mean Average]. The sections labeled AN15 and AN16/17 are incomplete with only '=' shown.
AN17	Give one worked example to calculate the Uncertainty in Repeats is calculated from the 'First IV' Repeated Data Points data using [(Max-min)/2] formula.	0	No worked example is provided for calculating uncertainty in repeats using the [(Max-min)/2] formula. The student shows a table with Min, Max, and Δm values but does not show the actual calculation steps.
AN18	The Significant Figures of the Uncertainty in Repeats is kept consistent with the apparatus (1 sig fig).	0	The uncertainty values in the processed data table (Δm column) are given to 3 decimal places (e.g., 0.024, 0.070) rather than 1 significant figure as required. They should be 0.02, 0.07, etc.
AN19	Calculate a Mean Average % Instrumental Uncertainty from both IV and DV data using the following formula: [Instrumental uncertainty/Mean change in IV value x 100 = % Uncertainty]. [Instrumental uncertainty/Mean change in Mean Repeated DV value x 100 = % Uncertainty].	0	No calculation of mean average % instrumental uncertainty is shown for either IV (pH) or DV (mass) using the required formula [Instrumental uncertainty/Mean change x 100 = % Uncertainty].
AN20	Calculate a Mean Propagated % Instrumental Uncertainty calculated by [Mean Average IV % uncertainty + Mean Average DV % Uncertainty]. Addition of all the % Uncertainty values used by IV and DV measuring devices. Devices used to confirm controlled variables should not be included in the calculation.	0	No calculation of propagated % instrumental uncertainty is shown. The section is incomplete with only 'Propagated instrumental uncertainty: AN28/29/30 (WHY ADDING them?)' mentioned.
AN21	Mean Propagated % Instrumental Uncertainty is calculated using the lowest numbers of Decimal Places on any of the different Measuring Device Instrumental Uncertainties.	0	No calculation demonstrating the use of lowest decimal places for propagated uncertainty is provided. The relevant section is not completed in the report.
AN22	Mean Propagated % Instrumental Uncertainty is quoted to 1 significant Figure	0	No propagated % instrumental uncertainty value is stated in the report, so it cannot be verified if it's quoted to 1 significant figure.
📷 AN23	An appropriate sized, scatter graph.	1	The scatter graph is appropriately sized, filling the page well without overwhelming other content, with a suitable scale that represents the data range from pH 7.4 to 9.0 and mass 3.7 to 4.6 g.
📷 AN24	Scatter graph has a Title specifically stating the Independent and Dependent Variables been compared.	1	Graph title 'Mass of crystal (g) vs pH of boric acid' explicitly states both the independent variable (pH) and dependent variable (mass of crystal).
📷 AN25	Scatter graph contains major grid lines.	1	The scatter graph contains major grid lines visible on both axes, forming a clear grid pattern across the plotting area.
📷 AN26	Scatter graph contains labelled IV vs DV axis labels.	1	Graph axes are labeled with 'pH of Boric acid' on x-axis and 'Mass of crystal' on y-axis, clearly identifying the IV and DV.
📷 AN27	Scatter graph contains IV vs DV 'Measurable' axis units.	1	Both axes include units - 'Mass of crystal (g)' on y-axis and 'pH of Boric acid' on x-axis (pH is dimensionless but this is understood).
📷 AN28	Scatter graph contains IV vs DV axis Instrumental Uncertainty values.	1	The x-axis label shows '(±0.01 ml)' which appears to be an error but instrumental uncertainty IS shown on the axis label. The y-axis shows '(±0.001 g)' uncertainty.
📷 AN29	Scatter graph contains uses crosses to plot data points.	0	Data points on the graph use circles/dots instead of X-shaped crosses as required by the criterion.
📷 AN30	A scatter graph trendline gradient equation shows the Final Relationship is given.	1	The main trendline equation y = 0.5701x - 0.5397 is shown on the graph, with the gradient value of 0.5701 quantifying the final relationship.
📷 AN31	Scatter graph trendline has a R2 value given.	1	R² value of 0.9517 is clearly displayed on the graph next to the main trendline.
📷 AN32	Horizontal 'Uncertainty bars' for IV are added to the scatter graph, using the IV Instrumental Uncertainty, to graphically show the actual values of the Uncertainty in Repeats. Any changes to this format should be justified.	0	No horizontal uncertainty bars are visible on the scatter graph for the IV (pH values).
📷 AN33	Vertical 'Uncertainty bars' for DV are added to the scatter graph to graphically show the calculated values of the Uncertainty in Repeats. Any changes to this format should be justified.	1	Vertical uncertainty bars are visible on each data point, representing the uncertainty in repeats calculated from the standard deviation data.
📷 AN34	A Maximium gradient trendline is calculated from the lowest vertical uncertainty bar and highest horizontal uncertainty bar on the first data point, to the highest vertical uncertainty bar and lowest horiztonal uncertainty bar on the last data point, with associated Trendline Equation. (Or Vice versa for negative slopes)	1	A maximum gradient trendline (green line) is visible on the graph with equation y = 0.6555x - 1.1987, drawn through the uncertainty extremes.
📷 AN35	A Minimum gradient trendline is calculated from the highest vertical uncertainty bar and lowest horizontal uncertainty bar on the first data point, to the lowest vertical uncertainty bar and highest horiztonal uncertainty bar on the last data point, with associated Trendline Equation. (Or Vice versa for negative slopes)	1	A minimum gradient trendline (orange line) is visible on the graph with equation y = 0.4763x + 0.3095, drawn through the opposite uncertainty extremes.
📷 AN36	Trendline equations for the Maximum and Minimum gradient trendlines are shown on the graph.	1	Both maximum gradient equation (y = 0.6555x - 1.1987) and minimum gradient equation (y = 0.4763x + 0.3095) are displayed on the graph.
AN37	Uncertainty in Final Relationship is calculated by [(Maximum gradient value-minimum gradient value)/2 = Uncertainty in Final Relationship] formula.	0	The section 'AN37: Uncertainty in final relationship:' is present but empty. No calculation using [(Maximum gradient - minimum gradient)/2] formula is shown.
AN38	State Uncertainty in Final Relationship units, using [Y axis units/X axis units] formula.	0	The section 'AN38:' is present but empty. No uncertainty units are stated in the format [Y axis units/X axis units].
AN39	State Uncertainty in Final Relationship to 1 Significant Figure	0	The section 'AN39:' is present but empty. No uncertainty value is stated to 1 significant figure.
AN40	Convert Uncertainty in Final Relationship into %Uncertainty in Final Relationship using the [Uncertainty in Final Relationship/Final Relationship gradient value x 100 = % Uncertainty in Final Relationship] formula.	0	The section 'AN40:' is present but empty. No calculation converting uncertainty to % uncertainty using the required formula is shown.
AN41	State %Uncertainty in Final Relationship to 1 Signficant Figure	1	The student states '%Uncertainty in Final Relationship to 1 Significant Figure: 20%' in CO7, which is correctly quoted to 1 significant figure.

Conclusion (9 criteria)

Code	Criterion	AI	Justification
CO1	The research question is answered by describing the IV-DV relationship gradient trend.	1	The student explicitly describes the IV-DV relationship gradient trend in the conclusion: 'In general, the higher the pH the lower amount of solution lost after crystallisation therefore a higher total mass of crystal.' This clearly states how changes in pH (IV) affect the mass of crystals (DV), indicating a positive relationship based on their scatter graph trendline.
CO2	The IV-DV relationship gradient equation is explicitly stated.	0	While the student states the equation 'y = 0.5701x – 0.5397', they fail to include the units with the gradient value. The gradient 0.5701 should have units of g/pH unit. To score 1, state the equation with units: 'y = 0.5701 g/pH unit × x – 0.5397 g' or explicitly state that the gradient is 0.5701 g/pH unit.
CO3	The IV-DV relationship gradient units are quoted in the conclusion.	0	The student does not explicitly state the gradient units in the conclusion. While they mention the equation, they never specify that the gradient of 0.5701 has units of g/pH unit. To score 1, explicitly state in the conclusion that 'the gradient of the pH-mass relationship is 0.5701 g/pH unit.'
CO4	Comment on gradient R2 value in terms of strength of correlation. (weak <0.3, moderate 0.3-0.7, strong >0.7)	1	The student correctly discusses the R² value of 0.952 and appropriately categorizes it as 'a very strong positive correlation' with a citation. This meets the requirement as 0.952 > 0.7, correctly placing it in the strong correlation category.
CO5	Accuracy of relationship is justified based on cited research of a similar area of study.	1	The student justifies the accuracy of their relationship by citing relevant research (Alavia et al., 2023; Şahin, 2002) about factors affecting crystal growth, including impurities and supersaturation control. The citations are properly formatted and directly relevant to boric acid crystallization without being so similar as to suggest plagiarism.
CO6	Hypothesis is re-stated and compared with final results and commented on in terms of trend and speculation as to the underlying chemistry causing this relationship.	1	The student restates their hypothesis ('I proposed that decreasing the pH of the borax solution with HCl would increase the mass of boric acid crystals produced'), compares it with results ('my initial hypothesis was incorrect'), and provides chemical speculation about underlying causes including impurity effects and supersaturation kinetics with proper citations.
CO7	% Uncertainty in Final Relationship from min-max trendlines is re-stated in the Conclusion.	0	The student only states '%Uncertainty in Final Relationship to 1 Significant Figure :' without providing the actual value. While 20% is mentioned in CO8, it's not explicitly restated in the conclusion section as required. To score 1, clearly state: 'The % uncertainty in the final relationship gradient is 20%.'
CO8	The magnitude of the %Uncertainty in Final Relationship gradient to potentially change the trend direction and invalidate the conclusion is commented on.	1	The student explicitly comments on the 20% uncertainty magnitude: 'This high uncertainty is suggesting that data is not very precise in defining the relationship between pH and the mass of the crystal produced after crystalization.' They acknowledge how this uncertainty affects the reliability of their conclusions.
CO9	Any concerns making the result invalid have been commented on. If the experiment has no obvious problems in its logic, leading to an invalid conclusion.	1	The student states 'Don't believe there is an obvious problem in logic leading to an invalid conclusion.' While brief, this indicates they have considered potential logical flaws and found none, which satisfies the criterion for a logically sound experiment.

Evaluation (13 criteria)

Code	Criterion	AI	Justification
EV1	Strengths of methodology are highlighted, based on trial run modifications if possible.	1	The student identifies strengths of methodology including trial run modifications (switching from beaker to evaporating dish for higher surface area, switching from sodium chloride to borax for faster crystallization) and explains how these improved efficiency. The clearly structured method is noted as a strength that helped data collection efficiency.
EV2	Equipment choice is evaluated to reduce Instrumental Uncertainties.	0	While the student mentions that 'other apparatuses used for our experiment were of the best quality available within the school,' they do not identify which equipment has the largest instrumental uncertainty nor suggest specific alternative equipment with lower uncertainties. The evaluation lacks specific uncertainty values when discussing equipment choices.
EV3	Comparison of a Mean Propagated % Instrumental Uncertainty vs % Uncertainty in Final Relationship from gradients is stated using [Mean Average IV % uncertainty + Mean Average DV % Uncertainty vs actual % Uncertainty in Final Relationship]	0	The section labeled 'EV3:' is empty in the report. There is no comparison of mean propagated % instrumental uncertainty versus % uncertainty in final relationship from gradients.
EV4	Major Methodological improvements suggested to improve accuracy and validity by identifying and removing specific Systematic errors that have become apparent during the experiment.	0	The student mentions calibrating the digital mass balance to reduce systematic errors but does not identify any MAJOR systematic errors that would make the experiment potentially invalid. The discussion focuses on minor improvements rather than addressing critical systematic issues.
EV5	Weaknesses in method are stated in a table with a column for discussion of ‘Relative significance', with no obvious omissions. Minor = negligible effect Moderate = some effect but manageable Major = substantial impact requiring attention Critical = severe impact undermining validity	1	A table of weaknesses is present with a 'Relative significance' column that uses qualitative assessments (Low, Medium, High). The table includes four weaknesses with their relative significance clearly stated.
EV6	Weaknesses in method are stated in a table with a column for ‘Error Type' and are correctly identified, with Systematic Errors only producing errors of the same magnitude and in the same direction each time and Random Errors producing errors of different direction and magnitude each time.	1	The table includes a 'Type' column that correctly identifies errors as either 'Random' or 'Systemic'. The systematic errors (cross contamination, crystallization in oven) are described as producing consistent effects, while random errors (fluctuating pH meter, inconsistent heating) are described as producing variable effects.
EV7	Weaknesses in method are stated in a table with a column for ‘Problems'.	1	The table of weaknesses includes a column labeled 'Problem' that clearly identifies and explains specific issues for each weakness listed (fluctuating pH meter readings, cross contamination, inconsistent heating, non-uniform oven temperature).
EV8	Weaknesses in method are stated in a table with a column for ‘Suggested Solutions'.	1	The table includes a column labeled 'Solution' with specific suggested solutions for each weakness. These are actionable improvements for future experiments (e.g., 'Clean the probe by rinsing it in water and drying it between samples', 'Preheating the oven helps ensure that the temperature is stable').
EV9	Improvements suggest increased Repeated data points and removal of outliers to reduce Random Errors, causing smaller Uncertainty in Repeats.	1	The student discusses both aspects required: increasing number of data points to minimize impact of errors and achieve smaller uncertainties, AND identifying and removing outliers 'which won't affect the end results'. The explanation links additional measurements to minimizing error impact and achieving 'more reliable average and clearer trends'.
EV10	Improvements suggested to expand the IV data range are made.	1	The student suggests specific values for expanding the IV range: 'expanding the range of independent variable (pH of the borax solution from 10 to 5)'. This is a specific suggestion with actual pH values provided.
EV11	Improvements suggested to narrow the IV data intervals are made.	1	The student suggests specific narrowing of IV intervals: 'narrowing the intervals of the IV (pH of the borax solution, in increments of 0.5)'. This compares to the existing 2 ml HCl increments and would provide finer resolution for observing subtle trends.
EV12	Minor Methodological improvements suggested to improve on the accuracy of the experiment.	1	The student suggests specific minor methodological improvements including routine calibration of measuring instruments (digital mass balance and pH meter) to enhance reliability of measurements. This is specific to the accuracy issues in this experiment.
EV13	Suggested extension investigations, that will adapt and improve this specific investigation are proposed.	1	The student suggests investigating 'how different concentrations of borax and HCl or varying the temperature during the crystallization process affects the overall mass of crystals yielded.' This builds upon the existing experiment by adding new variables that could affect the same dependent variable, helping to better understand the crystallization process.