The IA Is Your Best Opportunity to Secure Marks

The Internal Assessment (IA) contributes 20% of your final IB Physics grade.

Unlike examinations, the IA allows you to:

• Choose your investigation
• Plan your methodology
• Collect your own data
• Repeat measurements
• Improve your analysis
• Refine your final report

A strong IA can significantly boost your final grade and often becomes the difference between a 6 and a 7.

The students who achieve the highest IA scores are not necessarily those who perform the most complicated experiments. They are the students who demonstrate strong scientific thinking, careful data analysis, and thoughtful evaluation.

Understanding the Four Criteria

The Physics IA is assessed using four equally weighted criteria:

A successful IA requires strength in all four areas.

Criterion A: Research Design (6 Marks)

What Examiners Are Looking For

Research Design focuses on how well you plan and justify your investigation.

The examiner wants to see:

• A clear research question
• A focused investigation
• Appropriate variables
• A reproducible methodology
• Consideration of uncertainties and safety

Characteristics of a Strong Research Question

Weak question:

How does temperature affect resistance?

Strong question:

How does the temperature of a metallic conductor affect its electrical resistance over the range 20°C to 80°C?

A strong question should identify:

• Independent variable
• Dependent variable
• System being investigated
• Range of investigation

Variables Matter

Clearly identify:

Independent Variable

What you change.

Dependent Variable

What you measure.

Controlled Variables

What must remain constant.

For every controlled variable, explain:

• Why it matters
• How it is controlled

Avoid writing:

Length of wire kept constant.

Instead write:

The wire length was fixed at 1.00 ± 0.01 m throughout the experiment to ensure resistance changes were caused only by temperature.

Design for Quality Data

Aim for:

• At least 5–7 values of the independent variable
• Multiple repeats
• A wide enough range to reveal a clear trend

Examiners reward investigations that generate meaningful data.

Criterion B: Data Analysis (6 Marks)

What Examiners Are Looking For

This criterion evaluates how effectively you process and analyze your data.

The focus is not on collecting data.

The focus is on what you do with it.

Raw Data Must Be Complete

Include:

• Units
• Instrument uncertainties
• Repeated measurements

A strong table contains:

Every measurement should have a unit.

Process the Data Correctly

Show:

• Means
• Derived quantities
• Percentage uncertainties
• Absolute uncertainties
• Propagation of uncertainty

Do not simply present final values.

Examiners want to see the analytical process.

Graphs Are Extremely Important

A high-quality graph should contain:

• Appropriate scale
• Labelled axes
• Units
• Error bars
• Best-fit line or curve

The graph should occupy most of the available plotting area.

Show Sample Calculations

Include examples of:

• Mean calculation
• Uncertainty calculation
• Gradient calculation
• Derived quantity calculation

One clear sample is usually sufficient.

Criterion C: Conclusion (6 Marks)

What Examiners Are Looking For

The conclusion should directly answer the research question using evidence from your analysis.

Many students lose marks because they simply describe the graph.

A conclusion should interpret the results.

Use Evidence

Weak conclusion:

Resistance increased with temperature.

Strong conclusion:

Resistance increased linearly with temperature, as shown by the positive gradient of the graph. The relationship is consistent with the theoretical model for metallic conductors.

Support every statement with evidence.

Discuss the Relationship

Explain:

• Linear relationship
• Inverse relationship
• Exponential relationship
• Proportional relationship

Where appropriate:

• Calculate gradients
• Calculate constants
• Compare with accepted values

Compare With Theory

A strong conclusion connects results to established physics.

For example:

The calculated value of gravitational acceleration was 9.72 ± 0.18 m s⁻², which differs from the accepted value by 0.9%.

This demonstrates scientific understanding.

Criterion D: Evaluation (6 Marks)

What Examiners Are Looking For

Evaluation is often the weakest section of many IAs.

Students frequently list errors without explaining their impact.

Evaluation should demonstrate critical scientific thinking.

Identify Limitations Properly

Weak evaluation:

Human error affected the experiment.

Strong evaluation:

Human reaction time introduced uncertainty in the stopwatch measurements, increasing random uncertainty in the measured oscillation period.

Always explain:

• What the limitation was
• How it affected results
• Whether it caused random or systematic error

Suggest Specific Improvements

Weak improvement:

Use better equipment.

Strong improvement:

Replace the stopwatch (±0.2 s) with a photogate (±0.001 s) to reduce timing uncertainty and improve precision.

Specific improvements earn marks.

Generic improvements do not.

Link Improvements to Limitations

A strong evaluation follows this structure:

Limitation

What went wrong?

Impact

How did it affect the data?

Improvement

How could it be improved?

This structure mirrors scientific practice.

Common Mistakes That Prevent a 7

Choosing an Overly Complex Investigation

Complexity does not equal quality.

Simple investigations often score higher because:

• Data is cleaner
• Analysis is stronger
• Uncertainties are easier to evaluate

Collecting Too Little Data

Insufficient data limits:

• Trend analysis
• Reliability
• Evaluation quality

More high-quality data generally leads to stronger conclusions.

Ignoring Uncertainty

Many students calculate uncertainties but never use them.

Examiners expect uncertainty to influence:

• Analysis
• Conclusions
• Evaluation

Writing a Narrative Instead of a Scientific Report

Avoid excessive storytelling.

Focus on:

• Evidence
• Analysis
• Scientific reasoning

Every paragraph should contribute to the investigation.

IA Timeline for Success

Before Data Collection

• Finalize research question
• Identify variables
• Conduct background research
• Design methodology

During Data Collection

• Record everything
• Keep raw data
• Repeat measurements
• Photograph setups if useful

During Analysis

• Process data carefully
• Calculate uncertainties
• Construct graphs
• Check calculations

During Writing

• Answer the research question directly
• Support conclusions with evidence
• Evaluate limitations critically
• Propose realistic improvements

Characteristics of High-Scoring IA Topics

Successful IA topics typically have:

• Strong underlying physics
• Quantitative relationships
• Measurable variables
• Reliable equipment
• Opportunities for uncertainty analysis

Examples include:

• Pendulum investigations
• Hooke’s Law
• Electrical resistance
• Refraction and optics
• Thermal physics
• Oscillations

The best topic is not the most complicated topic.

It is the topic that allows you to demonstrate excellent science.

Final Checklist Before Submission

• Research question is clear and focused
• Variables are fully identified
• Methodology is reproducible
• Raw data includes units and uncertainties
• Data processing is complete
• Graphs include labels, units, and error bars
• Conclusions use evidence
• Results are compared with theory
• Limitations are explained scientifically
• Improvements are specific and justified
• References are properly cited
• Report is clear, concise, and professional

Final Thought

A Grade 7 IA is not produced by a perfect experiment.

It is produced by a student who thinks like a scientist.

The strongest investigations demonstrate:

• Careful planning
• Accurate measurements
• Thoughtful analysis
• Honest evaluation
• Clear scientific communication

Focus on quality of reasoning rather than complexity of experiment, and your IA can become one of the strongest components of your IB Physics grade.