The best IB Chemistry IA topic ideas combine four features: a variable you can alter systematically, an output you can measure accurately, a meaningful chemical context, and a method your school can support safely. A sophisticated-sounding topic is not automatically strong. A simple investigation with reliable measurements, justified decisions, and enough data for analysis is usually more workable than an ambitious experiment that cannot be controlled.
This guide explains how to move from a broad interest to a focused research question, compare strong and weak topics, test feasibility, and avoid choices that create problems later.
Understand what the Chemistry IA requires
Under the current course, first assessed in 2025, the Chemistry IA is officially called the scientific investigation. It is an open-ended investigation in which you gather and analyse data to answer your own research question. The written report has a maximum of 3,000 words, the task is allocated approximately 10 hours, and it contributes 20% of the final Chemistry grade at both SL and HL.
The report is assessed out of 24 marks using four equally weighted criteria:
Criterion
Maximum marks
What topic choice must allow you to do
Research design
6
Establish a focused question and justify a reproducible methodology
Data analysis
6
Process measurements appropriately and consider uncertainties
Conclusion
6
Answer the question using the processed data and accepted chemistry
Evaluation
6
Explain specific methodological weaknesses and realistic improvements
This structure affects topic selection. Your topic must produce more than an interesting demonstration. It needs enough quantitative evidence for meaningful analysis, a defensible conclusion, and an evaluation based on observed limitations.
The current course no longer has a separate criterion. However, a real-world connection can still help you explain why the investigation is worth conducting and make informed methodological choices. Interest is useful because it sustains careful work, not because mentioning a personal story automatically earns marks.
Use the variable, measurement, context, feasibility test
A workable topic can be screened using four questions.
1. Can you alter one variable systematically?
Choose an independent variable that can be changed in controlled, numerical steps. Temperature, concentration, reaction time, pH, electrode concentration, and particle size are common starting points because they can be linked to chemical theory.
Useful possibilities include:
Temperature, controlled with a water bath
Concentration, prepared through measured dilution
Surface area, approximated using defined particle-size ranges
pH, maintained using suitable buffer solutions
Reaction time, controlled with a consistent sampling schedule
Electrolyte concentration, investigated in an electrochemical cell
The values must be far enough apart to produce a detectable effect but not so extreme that the chemistry changes or the method becomes unsafe. A pilot study should determine the final range. Choosing five levels may be practical in many investigations, but the IB does not prescribe a universal number of values or repeats.
2. Can you measure a quantitative output?
Your dependent variable should be recorded with an instrument or derived transparently from measured data. Avoid outcomes based mainly on personal judgement, such as deciding when a colour “looks different.”
Measurable output
Possible equipment
Important limitation
pH
Calibrated pH probe
pH is logarithmic and probes require calibration
Gas volume
Gas syringe
Leaks and delayed sealing can reduce measured volume
Reaction rate
Gas volume, mass loss, absorbance or concentration over time
Rate should normally come from several time measurements
Temperature change
Temperature probe
Heat loss and calorimeter heat capacity affect results
Absorbance
Colorimeter or spectrophotometer
A calibration curve may be required
Concentration
Titration
Endpoint uncertainty and standardisation matter
Cell potential
Voltmeter
Electrode condition and temperature must be controlled
“Time taken until the reaction finishes” is often weaker than collecting a complete progress curve. A series of gas-volume readings, for example, can be used to calculate an initial rate and identify anomalous behaviour.
3. Is there a genuine chemical context?
A real-world hook should lead to chemistry rather than replace it. Food storage might lead to redox analysis of vitamin C, water quality to buffer capacity or ion concentration, and batteries to electrochemical potential.
Possible contexts include:
Stability of nutrients under different storage conditions
Effectiveness and chemistry of antacid formulations
Corrosion in waters with different ionic concentrations
Decomposition of household chemicals over time
Factors affecting electrochemical cells
Solubility or crystallisation in industrial processes
Start with something you have encountered, then identify the underlying chemical relationship. “I drink fruit juice” is not a rationale by itself. Investigating how storage temperature influences ascorbic acid oxidation, measured by redox titration, creates a testable chemical problem.
4. Can your school support it?
Feasibility includes equipment, chemical availability, lesson time, waste disposal, measurement precision, and teacher approval. Ask these questions before committing:
Are the chemicals available in suitable concentrations?
Can the equipment resolve the expected change?
Can all trials be completed within the allocated laboratory time?
Can temperature, pH, volume, and other controls be maintained?
Is there time for repeats and failed pilot trials?
Can waste be disposed of using school procedures?
Are the risks acceptable in a supervised school laboratory?
Consult your teacher before ordering materials or designing work involving volatile solvents, strong oxidising agents, high pressures, flames, or toxic metal compounds. The American Chemical Society's RAMP safety framework recommends recognising hazards, assessing risks, minimising risks, and preparing for emergencies.
Turn a broad interest into a research question
A useful research question identifies the variables, chemical system, measurement method, and relevant conditions. A practical template is:
How does [independent variable with units and range] affect [measured or calculated dependent variable with units] in [chemical system], as determined by [method]?
For example:
How does the temperature of an aqueous reaction mixture from 15.0 to 35.0 °C affect the initial rate of carbon dioxide production in the reaction between ethanoic acid and calcium carbonate, as determined by gas-syringe measurements?
This is more useful than “How does temperature affect reaction rate?” because it identifies what changes, what is measured, and which reaction is studied. The exact values should be confirmed by a pilot rather than invented before testing the apparatus.
Do not force every control variable into the research-question sentence. Instead, identify the most influential controls in the method, such as total solution volume, reactant amount, mixing procedure, pressure, particle size, or electrode immersion depth.
Strong and weak IB Chemistry IA topics
Strong topics are focused and analytical. Weak topics are often descriptive, categorical, uncontrolled, or dependent on subjective observations.
Weak starting point
Why it is weak
Stronger direction
What is the pH of different drinks?
Mainly produces a list of values with no continuous independent variable
Investigate how dilution affects the buffer capacity of one drink using titration
Which antacid brand is best?
Brands contain several uncontrolled differences, and “best” is undefined
Investigate how calcium carbonate particle size affects neutralisation rate under fixed acid conditions
How does temperature affect reaction rate?
The chemicals, range, method, and definition of rate are missing
Specify the reaction, temperature range, measurement method, and calculated initial rate
Does salt affect batteries?
“Salt” and “affect” are too vague
Investigate how electrolyte concentration affects the potential of a defined electrochemical cell
Which fruit has the most vitamin C?
Fruit type is categorical and biological variation is difficult to control
Investigate vitamin C degradation in one juice across controlled storage temperatures
Does surface area speed up reactions?
Surface area may not be quantified and other variables may change
Use sieved particle-size ranges and measure a gas-production rate under constant conditions
A familiar reaction is not automatically a poor choice. Originality can come from your variable range, context, measurement approach, or comparison with a theoretical model. Examiners reward the quality of the investigation, not novelty for its own sake.
A pilot experiment is the most reliable way to distinguish a workable idea from an attractive but impractical one. Conduct a small number of trials at the lower, middle, and upper parts of your proposed range.
Use the pilot to check:
Whether the effect is larger than the measurement uncertainty
Whether the reaction is too fast or too slow
Whether the apparatus leaks, drifts, or reaches its measurement limit
Whether the chosen range produces a trend
Whether control variables can be maintained
Whether the procedure generates manageable waste
Suppose gas production finishes before you can record the first reading. You might lower the concentration, reduce the temperature, collect data electronically, or choose a slower system. If the measured change is similar to the instrument uncertainty, improving the instrument or changing the variable range is more defensible than gathering many nearly indistinguishable results.
Common topic-selection mistakes
Choosing complexity instead of control
Multiple independent variables, elaborate syntheses, and unfamiliar analytical techniques create more opportunities for systematic error. One well-controlled variable usually supports a clearer conclusion.
Selecting the product before the chemistry
Comparing commercial products can introduce differences in formulation, age, additives, and manufacturing. If you use a commercial context, isolate one chemical quantity that can be measured and interpreted.
Ignoring the planned analysis
Decide how the data will be processed before collecting it. A rate investigation might require initial gradients, a calorimetry investigation may require energy calculations, and a colorimetry investigation may need a calibration curve. If you cannot describe the graph or calculation your data will produce, the topic is not yet ready.
Treating safety as an afterthought
A topic requiring unavailable ventilation, uncontrolled heating, or hazardous waste is not improved by an interesting research question. Reduce quantities, substitute safer substances, and follow your school's risk-assessment and disposal procedures.
Copying a published question
Looking at examples is useful for learning how variables are framed. Your final question, rationale, method, data, and report must remain your own. The IB states that AI-generated material included in assessed work must be acknowledged appropriately, so use Jojo AI to question your plan or identify possible controls rather than to produce work you submit as your own. The IB guidance on AI in assessment and your school's academic-integrity rules should guide your use.
A final topic approval checklist
Before confirming your topic, make sure you can answer yes to each statement:
I can state one focused independent variable and one quantitative dependent variable.
My independent variable can be changed systematically across a justified range.
My output can be measured with available equipment and suitable precision.
I can explain the relevant chemistry using course concepts.
I know which variables must be controlled and how to control them.
My pilot can be completed before full data collection.
I can collect enough repeated data to evaluate variation and uncertainty.
The procedure is safe, ethical, environmentally responsible, and teacher-approved.
I know what graph, calculation, or statistical treatment I expect to use.
The investigation can support a conclusion and specific evaluation, not merely a description.
Conclusion
A strong Chemistry IA topic is not the most complicated idea on the list. It is a focused chemical relationship with an adjustable variable, a precise measurement, a justified context, and a realistic school method. Refining the question through a pilot study is essential because it reveals whether the expected trend can actually be measured.
RevisionDojo's IB Chemistry resources can support the underlying theory, while the Chemistry IA grader can help you review a draft against the current criteria. Use Jojo AI and coursework tools to test your reasoning, then confirm the final design, safety arrangements, and permitted support with your Chemistry teacher.
Daniel holds an MSc in Chemistry from Imperial College London and has taught IB Chemistry for over 20 years, including as Head of Chemistry. His focus is on building the conceptual understanding behind each equation rather than rote recall.
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