Overview
The IB Chemistry Internal Assessment is worth 20% of your final grade. It is an individual scientific investigation totalling a maximum of 24 marks across four criteria. Your report must be no more than 3,000 words.
This criterion consists of several key components to ensure a well-structured investigation process. You must introduce a well-defined topic and state a research question, then provide contextual background information that demonstrates your knowledge and helps the reader understand the investigation. This includes definitions, characteristics of chemical components, and explanations of the relevant chemical processes.
You are expected to select a suitable methodology that will ensure the reliability and adequacy of obtained results. Justify your chosen methodology, list the necessary apparatus, and outline the sequential steps for conducting the research. Attention should also be given to safety, ethical, and environmental considerations throughout the report.
The research question must state the dependent and independent variables (or two correlated variables) and briefly describe the system in which the research question is embedded. You should also describe the method of analysis you intend to use.
- RQ clearly states the independent variable (IV) and dependent variable (DV), or two correlated variables
- Relationship between IV and DV is clearly investigated
- IV range is clearly stated in the research question
- The system and conditions are briefly described within the RQ
- The method of analysis is described
- Where relevant, the scientific name of the organism is used
📝 Example RQ Format
"What is the effect of (IV) on (DV) of (system, conditions, and controls)?"
Your background should provide the scientific context needed to understand your investigation. Focus your discussion on the independent and dependent variables, and explain why the relationship you are investigating is scientifically interesting or relevant. Make sure all claims are supported by cited sources.
- Relevant scientific theory, history, and applications are discussed
- Background information is focused on the IV and DV
- Background theory is of direct relevance to the research question
- A connection to the real world is established
- Hypothesis is clearly stated and justified scientifically
- All background is appropriately cited in-text, with a full reference list at the end
Your experimental design should explain and justify why your chosen methodology is the most appropriate way to answer the research question. If data is obtained through the school's large-scale activity, treat the investigation as a database investigation and focus the methodology on how the data is filtered and sampled from the whole database.
- Choice of methodology is justified with an explanation of why it is appropriate to answer the RQ within your specific parameters
- Explain the selection of methods for measuring the IV and DV
- Key steps of the methodology are explained and justified, with clear reasoning for why specific conditions are used
- Any decisions taken in designing a new (or modifying an existing) methodology are highlighted and explained
- Decisions regarding scope, quantity, and quality of measurements are discussed (range, interval or frequency of IV, repetition, precision)
- The design allows for the collection of sufficient data
- Provision for qualitative observations is stated
- Internally consistent with the rest of the report (an honest representation of the work actually done, not what should have been done in retrospect)
Identify the control variables and explain both the method and the reason for controlling them. Your IV should have a minimum of 5 values with a justified range.
- IV clearly stated with units and uncertainty, with justification for the choice of range (minimum of 5 values)
- DV stated with units and uncertainty
- Control variables presented in a table including: the variable to control, reasons for control (how it could affect IV/DV), and method of control (techniques and equipment used)
Address the safety, ethical, and environmental issues associated with the investigation. Present your risk assessment in a tabulated format. Consider all relevant aspects including handling, disposal, and any applicable IB policies.
- Tabulated risk assessment with columns for: description, hazard, and preventative measures
- Handling of chemicals or equipment is addressed
- Disposal of waste and alien species is considered
- Consumption of materials is addressed (if applicable)
- Handling of microbes is considered (if applicable)
- IB animal experimentation policy is applied (if applicable)
- Consent forms are used where necessary
- Impact on field sites is considered (if applicable)
Your methodology must include precise procedural steps and names of materials, and be detailed enough to allow for the investigation to be reproduced. Avoid including unnecessary or repetitive information so the reader can easily understand how the methodology was implemented.
- Apparatus is tabulated including sizes and uncertainties
- Chemicals are tabulated including concentrations and quantities
- An annotated diagram of the experimental setup is included
- Method is specific, clear, and detailed enough to be reproduced
- Unnecessary steps have been reviewed and removed
💡 Top Tip
If data is obtained through a school large-scale activity, treat the investigation as a database investigation. Focus your methodology on how data is filtered and sampled from the whole database, and explain the selection of the database or method of data sampling.
Your analysis should include the selection, processing, and interpretation of data to formulate conclusions regarding the topic of your study. What is crucial here is obtaining a sufficient amount of raw data capable of supporting your arguments. It is equally important to take into account accuracy in data processing, thus considering measurement uncertainties.
After obtaining the data, explore trends, patterns, and anomalies. Interpret them to formulate a valid conclusion. Graphical forms of interpretation such as graphs can be very useful for observing trends.
🎯 For Maximum Marks
Clearly communicate how the data was recorded and processed so that all steps are easily understood. Communicate in a precise manner: all graphs, tables, and figures should be appropriately annotated with correct units, decimal places, and significant figures. The work should not have any major inaccuracies, omissions, or inconsistencies that would prevent or limit the possibility of drawing a valid conclusion.
Present your raw data clearly, ensuring the origin of all data is transparent. Record both quantitative and qualitative observations.
- Data presented in a table with titles, units, and uncertainties, consistent with SI units
- Minimum range of 5 IV values and 5 trials (minimum 3 trials, optimum 5)
- Quality of data is appropriate for the investigation
- Origin of the presented data is clear
- Appropriate quantitative data is recorded in line with the method
- Data is recorded correctly with appropriate significant figures
- Appropriate qualitative data is also recorded
- Raw data is clearly distinguished from processed data
- All tables, figures, graphs, and schemes are clearly labelled
- In-text citations are used when appropriate to help the reviewer follow your work
Show your data analysis protocol clearly by providing an example of one of each type of calculation. Take care in selecting appropriate processing techniques, and ensure the processing is relevant to the research question.
- Calculations to determine DV are carried out and presented with titles, units, and uncertainties
- Data analysis protocol is clearly shown with a worked example of each calculation type
- All mathematics are correct
- Processed data and significant figures are consistent with the precision of raw data
- Care is taken in the selection of techniques to process the data
- Data analysis protocol is relevant to the RQ and produces appropriate results to address the research question
Show evidence of appropriate consideration of uncertainties. Account for the uncertainties in your measurements and conduct error propagation through the various mathematical operations used.
- Uncertainties in measurements and error propagation are considered throughout
- Uncertainties are described correctly
- Impact of uncertainties on the results is described
- Appropriate response to outlier data
- Degrees of precision of instruments used are stated
Choose appropriate graph types that enhance the reader's understanding and are directly relevant to addressing your research question. All graphs should be thoroughly annotated and analysed.
- Appropriate choice of graph that enhances understanding and is relevant to the RQ
- Graph axes are scaled appropriately
- Points are plotted accurately
- Error bars are calculated and displayed graphically (standard deviation, standard errors, ranges of maximum and minimum)
- Appropriate best-fit line is drawn
- Patterns and trends in the graph or tables are identified and explained
- Optima, maxima, and plateaus are identified where present
- Lines of maximum and minimum gradient are drawn (if appropriate)
- Comparisons and/or correlations between data sets are explored
- Statistical analysis calculations are interpreted
💡 Top Tip
Clearly communicate how data was recorded and processed so all steps are easily understood. The processing of the data must be relevant to the research question and carried out appropriately and accurately.
You are expected to formulate a conclusion that answers your research question based on the obtained findings and scientific context. Ensure that you use experimental values from the data analysis in the conclusion and critically evaluate the data. You should also provide a comparison of your experimental values to literature results.
🎯 For Maximum Marks
The conclusion must be fully supported and justified by the data analysis results. Include a relevant comparison to accepted scientific literature such as published papers, values, course notes, textbooks, or other outside sources (paper or online). Provide sufficiently detailed citations of the published materials to allow these sources to be traceable. Include the interpretation of processed data including associated uncertainties.
- Conclusion directly addresses and answers the research question
- Conclusion is consistent with and fully justified by the data analysis presented
- Directly reference specific tables and graphs in the conclusion
- Correctly interpret processed data, including consideration of uncertainties and their impact on the conclusion
- Include comparisons and/or correlations with relevant data
- Include a relevant comparison to accepted scientific literature (journal articles, science textbooks, encyclopaedia articles, or other peer-reviewed sources)
- Consider the extent of agreement or disagreement with established scientific understanding, and explore the reasons that may have contributed to your conclusion
- Provide sufficiently detailed citations so published sources are traceable
- Describe and justify the extent to which the data agrees with the research question and hypothesis
- Anomalous results are identified and explained
- Statistical analysis calculations are correctly interpreted
⚠️ Common Mistake
Do not simply state your conclusion without supporting it with data. Always reference specific numerical values, percentage errors, and trends from your analysis when justifying your conclusion. Vague statements like "the results support the hypothesis" without citing actual values will cost you marks.
Deepen your evaluation through the discussion of the strengths, weaknesses, and methodological issues of the report. Outline their influence on the findings and present suggestions for improving and extending the investigation.
Consider weaknesses related to control variables, the choice of equipment, choice of methodology, and any choices regarding the data-analysis processes used. Reflect on how these choices affected your conclusion and whether you would have made different choices given the opportunity.
- Relevant strengths of the report and investigation are discussed
- Specific methodological weaknesses or limitations are identified
- Weaknesses related to control of variables, choice of equipment, and methodology are all considered
- Reflection on the quality and sufficiency of data collected
- Identified weaknesses in the method and materials used
For each weakness, explain its relative impact on your results and conclusion. Consider how weaknesses affect the control of variables, the precision of measurement, or the variation in the data. Also consider whether the conclusion is limited in scope by the range of data collected, the confines of the system, or the applicability of any assumptions made.
- Explain the relative impacts of weaknesses regarding control of variables, precision of measurement, and data variation
- Explain how weaknesses limit the scope of the conclusion (range of data, system boundaries, assumptions)
- Reference error bars with regard to the validity of the conclusion
- Analysis of how appropriate the IV range was
- Possible effects of random errors are considered
- Possible effects of systematic errors are considered
- Measurement and instrument errors (accuracy and precision) are discussed
- Discussion of the reliability of the data
Consider the limitations of your investigation, including any assumptions made in the data analysis, the range of collected data, and the boundaries of the system investigated. Then propose realistic changes that could lead to more accurate results and/or extend the range and/or scope of the investigation.
- Realistic improvements are identified that are relevant to the identified weaknesses or limitations
- Each proposed improvement is explained in detail (not just listed)
- Consider limitations: assumptions made in data analysis, range of collected data, boundaries of the system
- The extent to which the obtained results are applicable is discussed
💡 Top Tip
Avoid vague weaknesses like "human error" or "more trials". Be specific: identify which variable was difficult to control, how it affected results, and what precise change would improve it. For example, instead of "temperature was hard to control", write "the exothermic reaction caused a 3 °C rise in the reaction mixture over 5 minutes, which could have increased the rate of reaction by approximately 15%, leading to higher yields than expected."
⚠️ Common Mistake
Do not just list weaknesses. Each weakness must be linked to its impact on the conclusion and followed by a realistic, explained improvement. Generic improvements like "use better equipment" will not score well.
Formatting Requirements
Maintain a clear structure throughout the essay and ensure that all formatting requirements are met. The word count does not include charts and diagrams, data tables, equations, formulas and calculations, bibliography, or headers.
| Requirement | Detail |
|---|---|
| Word limit | 3,000 words maximum (excludes charts, diagrams, data tables, equations, calculations, bibliography, and headers) |
| Font | Times New Roman, size 12 |
| Text alignment | Justified throughout. All text and data centred in table cells. |
| Title | The title of the investigation must be stated at the start of the report |
| Candidate code | IB candidate code provided at the beginning (do NOT put your name) |
| Word count | Stated at the start of the report |
| Page numbers | All pages must be numbered |
| Cover page | No cover page or contents page required |
Pre-Submission Checklist
Use this final checklist before submitting your IA to make sure nothing has been missed:
- Title is stated at the start of the report
- IB candidate code is included (no name)
- Word count is stated
- Word count is under 3,000 words
- Times New Roman, font size 12
- Text is justified, data is centred in table cells
- All pages are numbered
- No cover page or contents page
- Research question is clearly stated with IV, DV, and system
- Background information is relevant, focused, and fully cited
- Methodology is justified, detailed enough to reproduce, and free of unnecessary steps
- Variables table includes reasons and methods of control
- Risk assessment is tabulated with hazards and preventative measures
- Apparatus and chemicals are tabulated with uncertainties
- Annotated diagram is included
- Raw data has titles, units, uncertainties, and is clearly distinguished from processed data
- Minimum 5 IV values, minimum 3 trials (optimum 5)
- Sample calculations are shown for each calculation type
- Error propagation is included throughout
- Graphs have error bars, best-fit lines, labelled axes, and are properly annotated
- Trends, patterns, and anomalies are identified and interpreted
- Conclusion directly answers the RQ with specific data references
- Literature comparison with traceable, cited sources
- Uncertainties and their impact on the conclusion are discussed
- Agreement/disagreement with hypothesis is justified with data
- Specific weaknesses with explained impacts on the conclusion
- Random and systematic errors are discussed
- Realistic, explained improvements linked to identified weaknesses
- Limitations of scope and applicability are considered
- All sources are fully referenced in a bibliography