However, a good IA is not simply about carrying out an experiment and writing a report. Choosing the right research question, designing the experiment, processing the data and evaluating the results are all fundamental parts of the process.

In this guide, we will look at how to approach a science IA in the IB, the most common mistakes students make, and what you can do to develop a strong analysis.

What is the Internal Assessment in IB Physics or Chemistry?

The Internal Assessment is part of the internal assessment component of certain IB subjects. In Physics and Chemistry, it involves carrying out an individual scientific investigation related to the content and methods of the subject.

The aim is not simply to demonstrate that you can follow an experimental procedure. You need to show that you can:

• design an appropriate investigation;
• collect and process data;
• use scientific concepts to analyse it;
• interpret your results;
• evaluate the limitations of your method;
• and draw conclusions supported by your evidence.

For this reason, a science IA should be approached as a scientific investigation, rather than simply as an extended laboratory report.

The first step: choosing a good research question

One of the most important parts of the IA happens before you even start collecting data.

A good investigation needs a specific and feasible research question.

A question that is too broad makes it difficult to carry out a meaningful analysis. For example:

How does temperature affect a chemical reaction?

is too general.

A more specific question could be:

How does temperature affect the rate of reaction between sodium thiosulfate and hydrochloric acid?

The second question makes it much easier to identify what you are changing, what you are measuring and what relationship you want to investigate.

The same applies to Physics.

How does the length of a pendulum affect its period?

is a much more manageable investigation than a broad question about how pendulums work.

A good research question needs to be feasible

Before committing to a research question, ask yourself:

• Can I carry out this investigation with the equipment available?
• Can I collect enough data?
• Can I control the relevant variables?
• Do I have enough scientific and mathematical knowledge to analyse the results?
• Can the relationship between the variables be studied quantitatively?
• Will I be able to carry out a meaningful evaluation?

A question can be scientifically interesting while still being a poor choice for an IA if it cannot be investigated properly.

Don’t choose the experiment first and find a question afterwards

This is a common mistake.

A student finds an interesting experiment and thinks:

“I’ll do this and then work out what I can investigate.”

The problem is that you may end up with an experiment that produces data but does not allow you to carry out a sufficiently deep analysis.

It is better to start with the relationship you want to investigate and then design a method that allows you to study it.

For example, if you want to investigate how one variable affects another, you should think about the following from the beginning:

• which values you are going to use;
• how many measurements you need;
• which variables need to be controlled;
• how precise your instruments are;
• and what mathematical analysis you will carry out afterwards.

Designing the experiment correctly

Once you have a feasible research question, you need to design your investigation.

A good experimental design should clearly identify:

Independent variable

The variable that you deliberately change.

For example:

• temperature;
• length;
• concentration;
• mass;
• voltage;
• distance.

Dependent variable

The variable that you measure.

For example:

• time;
• velocity;
• period;
• absorbance;
• temperature;
• current.

Controlled variables

Variables that could affect the result and that you try to keep constant.

This is particularly important because if several variables change at the same time, it becomes difficult to determine what is causing the observed changes.

Collecting data is not enough

A science IA needs data that allows you to carry out a meaningful analysis.

Before starting the experiment, think about what data you will actually need to answer your research question.

In general, it is useful to have several values of the independent variable and repeated measurements where appropriate.

For example, if you are investigating a relationship between two variables, five data points may allow you to observe a trend, but a wider range and enough measurements can give you many more opportunities to analyse the behaviour of the relationship.

Repeating measurements can also help you identify:

• experimental variation;
• anomalous values;
• data spread;
• uncertainties;
• and the consistency of your results.

Uncertainties are an important part of the analysis

One of the things that distinguishes a strong scientific analysis from a superficial one is the treatment of uncertainties.

It is not enough to simply record your measurements.

You should consider the precision of your instruments and how uncertainties affect your results.

Depending on your investigation, this may involve:

• absolute uncertainties;
• relative or percentage uncertainties;
• propagation of uncertainties;
• error bars;
• and comparison of uncertainties between results.

For example, if two results appear to be different but their uncertainties overlap considerably, you cannot necessarily conclude that there is a significant difference.

Uncertainty should be used to interpret your data, rather than simply appearing as an additional number in your tables.

A graph is not just decoration

Another common mistake is including a graph because “you need to have a graph”.

A graph should help you analyse the relationship between the variables.

Depending on the investigation, you may want to study:

• the gradient;
• the intercept;
• linearity;
• correlation;
• the shape of the curve;
• possible deviations;
• or how well the data fits a theoretical model.

In some cases, a mathematical transformation of the data can allow you to test whether a particular relationship is consistent with a linear model.

For example, a relationship that initially appears curved may become linear after transforming one or both variables.

This can take your analysis much further than simply stating:

“The graph shows a positive relationship.”

Compare your results with a scientific model

A Physics or Chemistry investigation should not simply describe the data.

Where possible, you should relate your results to the scientific theory or model you are studying.

Ask yourself:

• Are the results consistent with the theory?
• Does the observed relationship have the expected form?
• Does the gradient have a physical or chemical meaning?
• Is the experimental value consistent with the theoretical value?
• Can differences be explained by the uncertainties?
• Is there any unexpected behaviour?

This connection between experimental data and the theoretical model is often much more valuable than simply presenting the results.

A good evaluation is not a list of errors

Evaluation is another area where many students miss opportunities.

A weak evaluation might say:

“A more precise instrument could be used.”

The problem is that this does not explain why that limitation matters.

A stronger evaluation should explain:

1. what the limitation is;
2. how it affects the results;
3. what evidence allows you to identify it;
4. and how the method could be improved.

For example, if human reaction time affects an experimental measurement, it is not enough to say that “reaction time introduces error”.

You should explain how this error may affect the data and what procedure could reduce its impact.

Not all sources of error are equally important

Another common mistake is producing a long list of possible sources of error.

You do not need to prove that the experiment is imperfect. All real experiments have limitations.

What matters is identifying the limitations that can actually affect your conclusion.

Instead of listing ten generic sources of error, it is usually more useful to analyse two or three relevant limitations in depth.

How long should an IA be?

There is no direct relationship between the quality of an IA and its number of pages. The 3,000-word limit means that you need to be concise and direct, while making sure that your work addresses the assessment criteria. The important thing is that each section contributes to answering the research question.

As for the time needed to produce a good piece of work, it is estimated that a student should dedicate around 40 hours to completing the IA, taking into account the preparation and execution of the experiment, data analysis and writing.

Common mistakes in a science IA

Before submitting your investigation, pay particular attention to these points:

1. The research question is too broad

If you cannot clearly explain which variables you are studying, you probably need to make your question more specific.

2. The experiment does not actually answer the question

Sometimes students collect a lot of data, but that data does not allow them to directly answer the research question they have proposed.

3. There is too much data and not enough analysis

A large table does not replace scientific interpretation.

4. Uncertainties are included but not used

Calculating an uncertainty is not very useful if you never consider it when interpreting your results.

5. The graph is not interpreted

It is not enough to include a trendline and mention the value of $R^2$. You need to explain what it means and what information it provides about your investigation.

6. The evaluation is generic

Saying that “using more precise equipment would improve the experiment” is not enough. Explain which source of uncertainty would be reduced and how this would affect your results.

7. You try to fill pages

The goal is not to produce the longest report possible. The goal is to build a clear, coherent and scientifically justified investigation.

When should you start your IA?

Don’t wait until the final weeks of the course. Ideally, you should make significant progress on your IAs before starting your second year of the IB.

The best time to start thinking about your IA is while you still have enough time to change your research question, repeat an experiment or improve your experimental design.

A good process could look like this:

Idea → research question → experimental design → data collection → processing → analysis → evaluation → conclusion

If you discover a problem during one of the early stages, you still have time to fix it.

If you discover it a few days before the deadline, your options will be much more limited.

In summary

A good Physics or Chemistry IA is not about carrying out a complicated experiment or writing a large number of pages.

It is about building an investigation in which there is a clear connection between:

Research question → method → data → analysis → conclusion → evaluation

Before you start, make sure that your research question is specific enough and that you can actually investigate it with the resources available.

During the experiment, think about the quality of your data and your uncertainties.

And during the analysis, try to go beyond describing what happens: use your data to explain the relationship between the variables and how far your results are consistent with the scientific model.

If you are preparing an IB Physics or Chemistry IA and have questions about your research question, experimental design or data analysis, I can help you review your approach and identify potential problems before you get too far into your investigation.

The goal is not to do the IA for you, but to help you understand what you are doing and why.

La entrada Internal Assessment (IA) in the IB: A Guide for Physics and Chemistry se publicó primero en Profesor de Bachillerato Internacional | Clases Online de Química, Física y Matemáticas IB.

And, on top of that, the assessment system is different from many other school programmes.

The good news is that you don’t need to understand everything about how the IB works from day one. What matters during Year 1 is understanding how the programme is organised, what is expected of you, and, above all, how to organise yourself from the beginning.

In this guide, we’ll explain how the International Baccalaureate works and what you should keep in mind when starting Year 1 of the IB.

What is the International Baccalaureate?

The Diploma Programme (IBDP) is a two-year educational programme normally aimed at students aged between 16 and 19.

Unlike a traditional school programme, the IB is not simply about passing final exams. The programme combines:

• The study of six subjects.
• External assessments.
• Internal assessments and coursework.
• Theory of Knowledge (TOK).
• The Extended Essay.
• The CAS programme (Creativity, Activity, Service).

Therefore, one of the first things a Year 1 IB student discovers is that studying for exams alone is not enough.

And this has an important consequence: organisation throughout the two years is essential.

What subjects do you study in the IB?

One of the defining features of the Diploma Programme is that students take six subjects, divided into six groups:

1. Studies in Language and Literature
2. Language Acquisition
3. Individuals and Societies
4. Sciences
5. Mathematics
6. The Arts

Students generally choose one subject from each group, although in certain cases, the Arts subject can be replaced by another subject.

For example, one student might take:

• English A
• Spanish B
• Economics
• Chemistry
• Mathematics AI
• Biology

while another may have a completely different combination.

Therefore, there is no single IB timetable or subject combination.

What do SL and HL mean?

This is probably one of the first things you’ll hear when you start the IB:

SL = Standard Level

HL = Higher Level

Of the six subjects, students take three at Higher Level and three at Standard Level.

HL subjects are studied in greater depth and generally involve a greater amount of content and teaching hours.

This does not mean that SL subjects are “easy” or that HL subjects are simply a version with more topics.

What subjects should I choose at HL?

This decision is particularly important if you already know what degree you want to study at university.

For example, certain science-related degrees may require or recommend having taken specific subjects at HL.

Therefore, you should not choose subjects simply because they seem easier to get a good grade in.

Before choosing them, it is advisable to check:

• What degree you want to study.
• Which universities you are interested in.
• What admission requirements they have.
• Which subjects and levels they recommend or require.

How is the International Baccalaureate scored?

Here we find another important difference compared with other education systems.

Each of the six subjects is normally graded from 1 to 7:

Therefore, the maximum score from the six subjects is:

6 × 7 = 42 points

But the Diploma Programme allows students to obtain up to 45 points.

Why?

Because, in addition to the six subjects, there are the core components of the programme.

What are TOK, CAS and the Extended Essay?

These three components form part of the core of the Diploma Programme and allow students to earn the additional 3 points towards their final IB score.

TOK — Theory of Knowledge

Theory of Knowledge (TOK) is a subject/component in which students reflect on questions related to knowledge.

It is not simply about memorising content.

The aim is to learn how to analyse questions such as:

• How do we know that something is true?
• What role does evidence play?
• How does our perspective influence us?
• What is the difference between an opinion and a well-supported claim?

TOK can seem quite strange at first precisely because it is not very similar to traditional subjects. It is assessed through an oral presentation and a 1,600-word essay, both of which challenge students to think critically and express their understanding of complex concepts.

Extended Essay

The Extended Essay (EE) is an independent research project that students carry out on a specific topic.

It has a maximum length of 4,000 words and requires students to formulate a research question, gather information, analyse it, and develop their own argument.

Although it is normally completed during Year 2, you should not think of it as a project to start just before the deadline.

Choosing a good topic and planning early can save you a huge amount of work later on.

CAS

Creativity, Activity, Service (CAS) is another compulsory component of the programme.

The idea is for students to take part in activities related to:

• Creativity
• Activity
• Service

It is not simply about accumulating hours by doing activities. CAS aims to encourage students to participate in experiences outside the purely academic environment and reflect on them. It does not receive a grade as such, but failing to meet the CAS requirements means that the student will not be awarded the Diploma.

How do IB exams work?

This is probably one of the biggest differences compared with other education systems.

Generally, a significant part of the final grade comes from external exams taken at the end of the programme, but exams are not necessarily the only form of assessment.

Depending on the subject, there may also be different internal assessment components, coursework, investigations, presentations, or projects.

This means that a student may find themselves in a situation quite different from what they expected:

“I can’t leave everything until April to study.”

And this is one of the main reasons why planning during Year 1 of the IB is so important.

What are Internal Assessments?

Internal Assessments (IAs) are assessment components completed during the programme and form part of the assessment of certain subjects.

Their format depends on the subject. In Sciences, for example, they involve carrying out a 3,000-word scientific investigation. The important thing to understand from the beginning is that IAs are not simply normal homework. They form part of your official assessment and can have a significant impact on your final grade. That is why it is important to take them seriously from the moment your teacher starts working on them.

What should I do during the first few months of Year 1 of the IB?

This is probably the most important part of the entire guide.

When you start the IB, it is very easy to make one mistake:

trying to study a huge amount from day one without having a system.

You do not need to study eight hours a day during September.

What you need is to build good habits.

1. Understand how each subject works

During the first few weeks, try to find out:

• What content you will study.
• How the subject is assessed.
• What assignments you will have to complete.
• How much weight each component carries.
• What types of questions appear in the exams.

This will allow you to study for the type of assessment you will actually have, rather than simply memorising the textbook.

2. Don’t let knowledge gaps build up

This is probably one of the best pieces of advice I can give you for Year 1 of the IB.

If you do not understand a concept in Maths or Chemistry in October and decide to leave it for later, by December you will probably have several concepts that depend on it.

And then catching up becomes much more difficult.

A small question resolved this week can save you several hours of work two months from now.

3. Start practising exam questions

Studying the theory is necessary, but not enough.

In the IB, it is very important to get used to how questions are phrased and what the examiner expects in your answers.

That is why, progressively, you should start working with:

• Exam questions.
• Markschemes.
• Past papers.
• Exercises specific to the type of assessment in your subject.

Especially in subjects such as Mathematics and Sciences, doing exercises is a fundamental part of learning.

4. Don’t leave your IAs until the last minute

When you are still in September or October of Year 1, it may seem like the Internal Assessments are a long way off.

But the year goes quickly.

If you work on them progressively, you will have much more time to:

• Change an idea that does not work.
• Improve your methodology.
• Analyse your results.
• Correct mistakes.
• Review your writing.

Trying to do everything at the end often turns a manageable task into a huge source of stress.

5. Start thinking about the Extended Essay early

You do not necessarily need to decide on your final topic as soon as you start Year 1.

But it is a good idea to start thinking about which subjects interest you.

If there is a subject you particularly enjoy, ask yourself:

Is there a specific question I would like to investigate in depth?

A good research question can make the EE much more interesting and manageable.

Is the International Baccalaureate difficult?

This is probably one of the questions students ask most before starting.

The honest answer is:

yes, it can be demanding, but the difficulty is not simply about the amount of content.

The IB requires you to combine:

• Knowledge.
• Understanding.
• Application.
• Analytical skills.
• Organisation.
• Time management.
• Independent work.

Therefore, a student who is used to getting good grades by studying only a few days before an exam may find the IB challenging.

On the other hand, a student who learns to work consistently and in an organised way can adapt perfectly well to the system.

So, how should I organise myself in Year 1 of the IB?

You do not need to have a perfect plan from day one.

A reasonable strategy could be:

During the first few weeks:
→ Understand the programme and familiarise yourself with each subject.

During the first term:
→ Build a study routine and identify your weak areas. Don’t get frustrated if your initial grades are not what you expected. It is normal to need a period of adjustment to the system, the way questions are answered, etc.

During the rest of Year 1:
→ Consolidate content, practise questions, and progressively work on your IAs.

Before finishing Year 1:
→ Try to enter Year 2 with a solid foundation and no major knowledge gaps. Ideally, use the summer to get all your IAs underway.

The goal is not to study constantly.

The goal is to avoid letting work pile up.

One final piece of advice for starting the IB

If you have just started Year 1 of the International Baccalaureate, you probably feel that there are too many things to keep track of right now.

That is completely normal.

You do not need to know how to do everything from the beginning.

During the first few weeks, focus on three things:

Understand the system → get organised → work consistently.

The IB becomes much more manageable when you stop seeing it as one huge set of tasks and start breaking it down into smaller parts.

And, above all, don’t wait until you are completely lost before asking for help. A specific question about Mathematics, Chemistry, or any other subject is much easier to solve when it first comes up than after several weeks of accumulating content you do not understand.

Do you need help with the International Baccalaureate?

If you are starting Year 1 of the IB and need support with Mathematics, Chemistry, Biology, or Physics, tutoring can help you consolidate the content from the beginning and, above all, become familiar with the types of exercises and assessments used in the programme.

If you would like to discuss your situation and design a personalised study plan, you can book a first consultation.

La entrada How the International Baccalaureate Works: A Guide to Starting the IB Diploma Programme se publicó primero en Profesor de Bachillerato Internacional | Clases Online de Química, Física y Matemáticas IB.

The good news is that the International Baccalaureate allows students to retake their exams through what is known as a Retake. In this guide, we explain how it works, who can do it, and when it is worth retaking the exams.

What is an IB Retake?

A Retake means sitting one or more International Baccalaureate exams again with the aim of improving the grade obtained in a previous examination session.

It is not necessary to repeat the entire programme or complete the two years of the Diploma again. Students can retake only the subjects they wish to improve, while still following the IB and school regulations.

Who can take an IB Retake?

Any student who has previously completed the Diploma Programme can request a Retake through an IB World School.

Many students choose this option when:

• They did not achieve the Diploma.
• They need to improve their grade to meet university admission requirements.
• They want to improve their result in a specific subject such as Chemistry, Physics, or Mathematics.

When can you retake IB exams?

The IB holds two official examination sessions each year:

• May
• November

Not all schools offer both examination sessions, so it is advisable to check with the school where you will register.

Do you have to retake all your subjects?

No.

One of the advantages of the system is that you can retake only the subjects you want to improve.

For example, if you achieved good grades in most subjects but need to improve your Chemistry HL grade to gain admission to a university degree, you can focus all your preparation on that subject.

Do you also have to repeat the Internal Assessment (IA)?

It depends on the circumstances.

In many cases, the Internal Assessment (IA) that was previously completed can be retained and combined with the new exam grade. However, there are situations in which it is possible to submit a new IA to improve its grade, provided the school authorises it and the requirements established by the IB are met.

For this reason, it is always advisable to check the current regulations and speak to your school’s Diploma Programme Coordinator.

Is an IB Retake worth it?

The answer depends on your goals.

It can be an excellent option if:

• You need to improve your grade to gain admission to a university.
• You were close to achieving the Diploma.
• You know you can make a significant improvement with better preparation.

Many students manage to increase their score by one or several points simply because they already know the exam format and can prepare for the examination session with a much more efficient strategy.

How to prepare for an IB Retake successfully

A common mistake is studying in exactly the same way as the first time.

For a Retake, the most important thing is to identify what went wrong previously.

Some recommendations include:

• Analyse the results obtained in each Paper.
• Practise with official past papers.
• Focus on the topics that cause the most difficulties.
• Become familiar with the mark schemes used by the IB.
• Set a realistic study schedule.

In many cases, a few weeks of well-focused preparation can produce better results than months of unstructured study.

Do you need help preparing for your Retake?

If you are going to retake your International Baccalaureate exams, personalised preparation can make a difference.

I work with students studying IB Chemistry, Physics, and MAA, at both SL and HL, helping them identify their weaknesses, prepare for the different Papers, and approach the examination session with a strategy tailored to their goals.

If you would like to discuss your situation and design a personalised study plan, you can book a first consultation.

La entrada Retaking the IB: How to Retake International Baccalaureate Exams in 2026 se publicó primero en Profesor de Bachillerato Internacional | Clases Online de Química, Física y Matemáticas IB.