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":	0	The question 'How does salt affect ice melt?' is self-evident from studying chemistry. It's well-established that salt lowers the freezing point of water through colligative properties. This is directly covered in IB Chemistry syllabus under colligative properties and is easily answered through online searches.
RD2	Aim is focused in its breadth, investigating at a single relationship.	1	The aim focuses on a single relationship between amount of salt (IV) and melting time (DV). While the student mentions 'mass of ice' as IV in variables section, the actual experiment focuses solely on salt amount vs melting time relationship.
RD3	Aim wording is specific, so the reader knows exactly what the investigation is about.	0	The aim lacks specificity - it doesn't state the range of salt amounts being tested (0-15g) or specify that it's table salt/NaCl. A specific aim would be: 'How does the mass of NaCl (0-15g) affect the melting time of ice cubes?'
RD4	Sufficiently appropriate referenced science background affecting the Dependent Variable (DV) to allow understanding of the investigation.	0	The background section is too vague and lacks specific chemistry. It mentions 'hydrogen bonds' and 'particles vibrating' but doesn't explain the actual chemistry of freezing point depression, colligative properties, or the specific mechanism. No in-text citations are present in the background section.
RD5	Sufficiently appropriate referenced science background explaining how the Independent Variable (IV) will potentially cause changes in the measured Dep	0	The background doesn't adequately explain HOW salt causes ice to melt faster. It vaguely mentions 'break down hydrogen bonds' but lacks the scientific explanation of freezing point depression and ion-dipole interactions. No in-text citations support the IV-DV relationship.
RD6	Valid hypothesis is justified by logical scientific reasoning and the chemistry is accurate and testable by the method.	0	No hypothesis is stated in the report. The student jumps from background to variables without presenting a testable hypothesis about the expected relationship between salt amount and melting time.
RD7	Quantitative 'Measurable' Independent Variable (IV) to be manipulated is stated and used consistently when referenced throughout the report.	1	The IV is consistently stated as 'amount of salt' with specific quantitative values (0g, 3g, 6g, 9g, 12g, 15g) throughout the report.
RD8	Quantitative Independent Variable (IV) to be manipulated has correct units stated.	1	The IV units are correctly stated as grams (g) for the amount of salt.
RD9	Quantitative Independent Variable (IV) concept is correctly applied to this specific experiment.	1	The IV concept of varying salt mass is correctly applied to this experiment investigating ice melting rates.
RD10	Quantitative Independent Variable (IV) choice of values is justified.	0	No justification is provided for why these specific salt values (0, 3, 6, 9, 12, 15g) were chosen. The student doesn't explain why they started at 3g or why they stopped at 15g.
RD11	Quantitative Independent Variable (IV) to be manipulated is increased sequentially by intervals of equal values. Any deviation from this format is jus	1	The IV increases in equal intervals of 3g throughout (0, 3, 6, 9, 12, 15g).
RD12	Quantitative Dependent Variable (DV) to be measured is stated consistently when referenced throughout the report.	1	The DV is consistently referred to as 'time taken to melt' or 'melting time' throughout the report.
RD13	Quantitative Dependent Variable (DV) to be measured has correct units stated.	1	The DV units are correctly stated as seconds in the variables section.
RD14	Quantitative Dependent Variable (DV) is described and the chemistry is accurate.	1	The DV is clearly described as the time taken for ice to completely melt, measured in seconds using a stopwatch.
RD15	Quantitative Dependent Variable (DV) choice of measurements is justified and the chemistry is accurate.	0	No justification is provided for why measuring melting time is the best method to investigate this relationship. The student doesn't explain why time measurement was chosen over other possible DVs.
RD16	All Controlled Variables (CV) are identified in a table, with no obvious omissions.	0	CVs are listed but not in a table format. Major omissions include: ice cube size/mass (mentioned but not controlled), type/brand of salt, initial temperature of ice, container material, and volume of ice.
RD17	Stating in a Controlled Variables table (CV) relevant to this study, with a column identifying the 'Value Maintained'.	0	No CV table is present. The CVs are listed in prose but lack specific values - 'Temperature in the room' doesn't specify the actual temperature maintained.
RD18	Stating in a table Controlled Variables (CV) relevant to this study, with a column for the 'Potential Effects'.	0	No CV table with potential effects column is present. The environmental considerations section mentions some effects but not in the required table format.
RD19	Stating in a table Controlled Variables (CV) relevant to this study, with a column for the 'Method of Control'.	0	No CV table with method of control column is present. While some control methods are mentioned in environmental considerations, they're not in the required table format.
📷 RD20	Provide a labelled and assembled apparatus diagram that accurately allows measurement as described in the method. (chemix.org)	0	No apparatus diagram is present. The methodology mentions 'photo needed' but no diagram showing the experimental setup with labeled equipment (beakers, ice cubes, scale, stopwatch) is provided.
RD21	All Equipment, sizes, absolute uncertainties, and amounts required for the experiment are listed or stated in the Equipment List	0	Equipment list lacks critical details: no uncertainties for weighing scale or stopwatch, no sizes for beakers, no specification of ice cube container size, no concentration/purity of salt specified.
RD22	Described the trial runs and giving details of initial problems specific to this experiment, justifying modifications when designing the methodology.	0	No trial runs or initial problems are described. The student doesn't discuss any modifications made during method development.
RD23	3rd person, past tense, step-by-step method to carry out the investigation.	0	Method is written in imperative mood (commands) not third person past tense. Uses 'Put', 'Measure', 'Repeat' instead of 'was put', 'was measured', 'was repeated'.
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 crucial details: doesn't specify ice cube size/mass to use, doesn't specify exact placement of ice in beaker, doesn't define 'fully melted', doesn't specify observation intervals, room temperature not specified.
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 includes 6 IV values (0, 3, 6, 9, 12, 15g), which exceeds the minimum requirement of 5 changes.
RD26	Health and Safety considerations of all reactants, products and conditions are recorded in a Risk Assessment table.	0	No Risk Assessment table is present. The 'Ethical considerations' table at the end discusses some safety but not in proper risk assessment format and doesn't cover all reactants/products.
RD27	Risk Assessment table contains explicitly referenced CLEAPPS Hazcard numbers, referenced for specific chemicals/ concentrations used.	0	No CLEAPSS Hazcard numbers are referenced anywhere in the report. The word 'CLEAPSS' appears once but without any hazcard numbers.
RD28	Risk Assessment table contains explicitly referenced CLEAPPS Hazcard numbers, referenced for specific disposal of materials used or produced.	0	No disposal methods are mentioned and no CLEAPSS Hazcard disposal references are provided.

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.	0	The raw data table shown (Trial run 5) has IV values in the top row (0, 3, 6, 9, 12, 15g) rather than in the first column. The correct format requires IV in the first vertical column with DV repeats in subsequent columns to the right.
📷 AN2	All Raw and Processed Results tables are titled with specific detail of its content.	0	The visible table is labeled 'Trial run 5' but lacks a specific descriptive title explaining what data it contains (e.g., 'Table showing ice mass remaining at different salt concentrations'). References to Table 1 and Table 2 in text have no corresponding titled tables visible.
📷 AN3	Data table column headings include 'Measurable' units.	1	The data table shows column headings with units: 'amount of NaCl (g)' and 'Ice mass (g)' both include units in brackets as required.
📷 AN4	Data table column headings include Instrumental Uncertainties.	0	No instrumental uncertainties are shown in the data table column headings. The table should show uncertainties like '±0.01g' for the scale measurements but these are absent.
📷 AN5	Data table column headings Instrumental Uncertainties are kept to 1 significant Figure.	0	Cannot be scored as 1 since instrumental uncertainties are not present in the column headings (AN4=0).
📷 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 f	1	The data table is clearly formatted with adequate column widths, readable font size, and no page breaks disrupting the table structure.
AN7	All Instrumental Uncertainties from measuring devices are justified. (Analogue = Half the smallest readable digit, Digital = Smallest Readable digit,	0	The report does not justify instrumental uncertainties for any measuring devices. While the student mentions using a weighing scale and stopwatch, there is no statement about their uncertainties (e.g., ±0.1g for digital scale, ±0.01s for stopwatch). The student needs to explicitly state and justify the uncertainty for each measuring instrument used.
📷 AN8	The Decimal Points of raw and processed data are consistent with Instrumental Uncertainties on measurements	0	Data is recorded to different decimal places inconsistently (e.g., 18.63, 74.41.0, 60.47.9). Without stated instrumental uncertainties, cannot verify if decimal places match instrument precision.
AN9	Qualitative observations Before, During, and After are recorded that will assist with interpretation.	1	The report includes detailed qualitative observations throughout the experiment. Before/During observations include: 'The surface of the ice has dents after having contact with NaCl', 'ice cube gets smaller quicker when more salt is placed', 'Salt gets crystalized when ice is present'. After observations include: 'Salt gets dissolved when water is present after ice has melted', 'when too much salt is present, salt takes more time to dissolve'. These naked-eye observations complement the quantitative data.
📷 AN10	Qualitative observations are backed up by photographic evidence of the experiment	0	While qualitative observations are described in text (dents on ice surface, crystallization of salt), no photographic evidence is provided to support these observations.
AN11	Attempts are made to repeat measurements, until they are within the Instrumental Uncertainty limits set out by the apparatus.	0	While the student conducted multiple trials (6 trials shown in tables), there is no explicit mention of attempting to repeat measurements until they fell within instrumental uncertainty limits. The student needs to state that they attempted to achieve consistency within instrumental uncertainties, even if ultimately unsuccessful.
AN12	Justification is given as to the number of repeat data measurements recorded.	0	The report shows 6 trials were conducted but provides no justification for why data collection was halted at 6 trials. The student needs to explain why 6 trials was deemed sufficient (e.g., consistency achieved, time constraints, variability stabilized).
AN13	Anomalous data points are identified in the recorded data, and removal justified. [No stdv mathematical requirement].	1	The report identifies anomalous data points in Table 1 (marked in red) and provides justification: 'the anomalies indicate that the time it has taken is either higher or lower than the other data in the column. For example, the time taken on trial run 2 with 0g of salt placed in the beaker took less time than 3g salt placed in the beaker, suggesting that some errors have been made during the trial run.' Table 2 shows data with anomalies removed.
AN14	If the experiment requires any processing through additional equations, then any necessary calculations in order to process data are complete and with	1	The experiment directly measures time taken for ice to melt at different salt concentrations. No additional equations are necessary to process the raw data into the dependent variable. The DV (melting time) is directly measured, not calculated from other measurements.
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 Work	0	The report does not explicitly state which IV value will be used for the worked example calculation of mean average. While data is presented for all salt amounts (0g, 3g, 6g, 9g, 12g, 15g), the student needs to clearly state 'I will use the 0g salt data for my worked example' or similar.
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]. While mean values appear in the tables, the actual calculation steps are not 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] formul	0	No worked example is provided for calculating uncertainty in repeats using the [(Max-Min)/2] formula. While uncertainty values appear in Table 2, the calculation process is not demonstrated.
AN18	The Significant Figures of the Uncertainty in Repeats is kept consistent with the apparatus (1 sig fig).	0	Cannot verify if uncertainty in repeats is kept to 1 significant figure as the raw calculations are not shown. While Table 2 shows uncertainty values, without seeing the calculation process and original values, consistency with 1 sig fig cannot be confirmed.
AN19	Calculate a Mean Average % Instrumental Uncertainty from both IV and DV data using the following formula: [Instrumental uncertainty/Mean change in IV	0	No calculations are shown for mean average % instrumental uncertainty for either IV or DV. The formula [Instrumental uncertainty/Mean change x 100] is not applied. The student needs to calculate % uncertainty for the weighing scale (IV) and stopwatch (DV).
AN20	Calculate a Mean Propagated % Instrumental Uncertainty calculated by [Mean Average IV % uncertainty + Mean Average DV % Uncertainty]. Addition of all	0	No calculation of mean propagated % instrumental uncertainty is shown. The student needs to add the IV % uncertainty and DV % uncertainty values (once calculated) to show total propagated uncertainty.
AN21	Mean Propagated % Instrumental Uncertainty is calculated using the lowest numbers of Decimal Places on any of the different Measuring Device Instrumen	0	Cannot verify this criterion as no propagated uncertainty calculations are shown. The student needs to first complete the % uncertainty calculations, then ensure decimal places match the least precise measuring device.
AN22	Mean Propagated % Instrumental Uncertainty is quoted to 1 significant Figure	0	No mean propagated % instrumental uncertainty value is stated in the report. Cannot verify if it would be quoted to 1 significant figure.
📷 AN23	An appropriate sized, scatter graph.	1	The scatter graph is appropriately sized, fills the space well without being too small or overwhelmingly large, and uses a suitable scale that represents the data range effectively.
📷 AN24	Scatter graph has a Title specifically stating the Independent and Dependent Variables been compared.	1	The graph title 'Time taken for ice to melt vs amount of salt placed' explicitly states both the independent variable (amount of salt) and dependent variable (time taken) being compared.
📷 AN25	Scatter graph contains major grid lines.	1	The scatter graph clearly shows major grid lines on both axes forming a visible grid pattern across the plotting area.
📷 AN26	Scatter graph contains labelled IV vs DV axis labels.	1	The axes are clearly labeled with 'Amount of salt placed (g)' on the x-axis and 'Mass of ice cube (g)' on the y-axis.
📷 AN27	Scatter graph contains IV vs DV 'Measurable' axis units.	1	Both axes include units: x-axis shows '(g)' for grams of salt and y-axis shows '(g)' for mass of ice cube.
📷 AN28	Scatter graph contains IV vs DV axis Instrumental Uncertainty values.	0	No uncertainty values are shown on the axis labels. The axes only show 'Amount of salt placed (g)' and 'Mass of ice cube (g)' without any uncertainty values like '±0.01g'.
📷 AN29	Scatter graph contains uses crosses to plot data points.	0	The data points on the graph use circles/dots rather than X-shaped crosses as required.
📷 AN30	A scatter graph trendline gradient equation shows the Final Relationship is given.	1	The main trendline equation 'y = -10.596x + 248.44' is shown on the graph, providing the quantitative relationship between variables.
📷 AN31	Scatter graph trendline has a R2 value given.	1	The R² value of 0.9595 is clearly displayed next to the main trendline equation on the graph.
📷 AN32	Horizontal 'Uncertainty bars' for IV are added to the scatter graph, using the IV Instrumental Uncertainty, to graphically show the actual values of t	0	No horizontal uncertainty bars are visible on any data points on the graph.
📷 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	1	Vertical uncertainty bars are clearly visible on all data points showing the uncertainty in the dependent variable measurements.
📷 AN34	A Maximium gradient trendline is calculated from the lowest vertical uncertainty bar and highest horizontal uncertainty bar on the first data point, t	1	A maximum gradient trendline is visible on the graph (upper orange/red line) with equation 'y = -9.29x + 236.7', 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	1	A minimum gradient trendline is visible on the graph (lower line) with equation 'y = -14.086x + 294.24', drawn through the uncertainty extremes.
📷 AN36	Trendline equations for the Maximum and Minimum gradient trendlines are shown on the graph.	1	Both trendline equations are clearly shown on the graph: 'y = -9.29x + 236.7' for maximum gradient and 'y = -14.086x + 294.24' for minimum gradient.
AN37	Uncertainty in Final Relationship is calculated by [(Maximum gradient value-minimum gradient value)/2 = Uncertainty in Final Relationship] formula.	0	No calculation of uncertainty in final relationship is shown using the [(Maximum gradient - Minimum gradient)/2] formula. While the graph shows three trendlines, the actual calculation is not demonstrated.
AN38	State Uncertainty in Final Relationship units, using [Y axis units/X axis units] formula.	0	The uncertainty in final relationship is not stated with units. The units should be [seconds/gram] based on the axes (time/amount of salt), but this is not explicitly stated anywhere in the report.
AN39	State Uncertainty in Final Relationship to 1 Significant Figure	0	No uncertainty in final relationship value is stated, so cannot verify if it is expressed to 1 significant figure.
AN40	Convert Uncertainty in Final Relationship into %Uncertainty in Final Relationship using the [Uncertainty in Final Relationship/Final Relationship grad	0	No calculation shown converting uncertainty in final relationship to % uncertainty using the formula [Uncertainty in Final Relationship/Final Relationship x 100].
AN41	State %Uncertainty in Final Relationship to 1 Signficant Figure	0	No % uncertainty in final relationship is stated in the report, so cannot verify if it would be expressed 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 clearly describes the IV-DV relationship gradient trend in the conclusion: 'the negative correlation between the amount of salt placed in the beaker and the mass of the ice cube allows us to conclude that when more amount of salt is present, the ice cube will melt quicker.' This directly addresses the trend based on their scatter graph analysis.
CO2	The IV-DV relationship gradient equation is explicitly stated.	0	While the graph analysis mentions gradient calculations and the graph shows trendline equations, the student never explicitly states the IV-DV relationship gradient equation in the conclusion or elsewhere in the report. To score 1, include the specific equation (e.g., y = -8.99x + 179.3) with proper variable labels.
CO3	The IV-DV relationship gradient units are quoted in the conclusion.	0	The conclusion does not state the units for the gradient relationship between salt amount and melting time. To score 1, explicitly state the gradient units (e.g., seconds per gram or s/g) in the conclusion section.
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 states 'the R2 value is nearly close to 1 with a value of 0.96, suggesting a strong correlation between both variables' which correctly interprets R² = 0.96 as a strong correlation (>0.7) according to the specified ranges.
CO5	Accuracy of relationship is justified based on cited research of a similar area of study.	0	While the student mentions 'simulations in the websites shows that NaCl affects the melting kinetics' and provides a bibliography, there are no proper in-text citations in the conclusion or discussion sections. To score 1, include specific in-text citations (e.g., (Author, Year)) when referencing research.
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	0	The initial hypothesis is never explicitly stated in the report, making it impossible to compare it with the final results. To score 1, clearly state the original hypothesis and then explicitly compare it with the experimental findings in the conclusion.
CO7	% Uncertainty in Final Relationship from min-max trendlines is re-stated in the Conclusion.	0	The % uncertainty in final relationship from min-max trendlines is not stated in the conclusion. While uncertainty calculations appear in the data tables, the specific % uncertainty value for the gradient is not restated in the conclusion. To score 1, calculate and explicitly state this percentage in the conclusion.
CO8	The magnitude of the %Uncertainty in Final Relationship gradient to potentially change the trend direction and invalidate the conclusion is commented	0	There is no discussion about how the magnitude of % uncertainty in the gradient could potentially change the trend direction or invalidate the conclusion. To score 1, specifically discuss whether the uncertainty is large enough to reverse the negative correlation or affect the validity of 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 conclusio	1	The student identifies a major concern: 'the average data collected in the table does not match with the minimum nor maximum trendline, suggesting that there could be other factor that influenced the process.' This demonstrates awareness of potential issues that could affect the validity of results.

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 including 'Simple and effective' methodology allowing quick replication and data collection, and 'Varied conditions' testing multiple salt amounts for comprehensive understanding. These are presented in a table format and explain how the methodological design improves experimental effectiveness.
EV2	Equipment choice is evaluated to reduce Instrumental Uncertainties.	0	The student does not evaluate equipment choices to reduce instrumental uncertainties. There is no discussion of specific uncertainty values for equipment like the scale or stopwatch, nor suggestions for alternative equipment with lower uncertainties.
EV3	Comparison of a Mean Propagated % Instrumental Uncertainty vs % Uncertainty in Final Relationship from gradients is stated using [Mean Average IV % un	0	No comparison is present between mean propagated instrumental uncertainty (IV + DV %) and the actual % uncertainty in the final relationship from gradients. The student does not calculate or state these values anywhere in the report.
EV4	Major Methodological improvements suggested to improve accuracy and validity by identifying and removing specific Systematic errors that have become a	0	While systematic errors are identified in the table, no MAJOR methodological improvements are suggested to address errors that would make the experiment potentially invalid. The errors mentioned (reading instructions, ice cube measurement timing) are relatively minor.
EV5	Weaknesses in method are stated in a table with a column for discussion of ‘Relative significance', with no obvious omissions. Minor = negligible eff	0	The evaluation tables do not include a 'Relative significance' column assessing the impact of each weakness as minor/moderate/major/critical. The tables only have 'Explanation' and 'How to control' columns.
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 o	0	While the student has separate tables for 'Systematic Error' and 'Random Error', there is no 'Error Type' column within a single table. Additionally, the systematic errors listed don't explicitly state they produce errors of the same magnitude and direction each time.
EV7	Weaknesses in method are stated in a table with a column for ‘Problems'.	1	The evaluation section contains tables with weaknesses listed under 'Systematic Error' and 'Random Error' headers. Each entry identifies and explains specific problems like 'Inaccurately reading the instructions' and 'Stopping the stopwatch'.
EV8	Weaknesses in method are stated in a table with a column for ‘Suggested Solutions'.	1	The evaluation tables include a 'How to control' column providing suggested solutions for each identified weakness, such as 'Read the instructions carefully before conducting the trials' and 'start the trials immediately instead of measuring all of the ice at once'.
EV9	Improvements suggest increased Repeated data points and removal of outliers to reduce Random Errors, causing smaller Uncertainty in Repeats.	0	The student does not suggest increasing repeated data points or discuss outlier removal to reduce random errors. While outliers are identified in the data table, there's no discussion of how increasing repeats would allow for better outlier identification through narrower standard deviation.
EV10	Improvements suggested to expand the IV data range are made.	0	No specific suggestions for expanding the IV data range are made. The student does not propose testing salt amounts beyond 0-15g with specific new values.
EV11	Improvements suggested to narrow the IV data intervals are made.	0	No specific suggestions for narrowing IV data intervals are made. The student does not propose testing intermediate salt amounts between the current 3g intervals with specific values.
EV12	Minor Methodological improvements suggested to improve on the accuracy of the experiment.	1	The student suggests specific minor methodological improvements in the evaluation table: reading instructions more carefully and measuring ice cubes immediately before use rather than all at once. These are feasible improvements specific to this experiment.
EV13	Suggested extension investigations, that will adapt and improve this specific investigation are proposed.	0	No extension investigations are proposed. The student does not suggest any modifications or adaptations that would build upon this specific investigation to improve understanding of salt's effect on ice melting.