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A Guide to Acing your IB Physics IA

IB Physics is internationally regarded as one of the most challenging high school physics courses around. With two years’ worth of conceptually difficult content, countless past papers to mull over, and examiners looking to test the boundaries of your knowledge, a high score in your Physics IA is essential to achieve high marks and can take loads of pressure off your final exams. In this guide, I’ll tell you exactly how I obtained a perfect 24/24 on my Physics IA, covering topic selection, research, and mark maximisation in each criterion.

Topic Selection

Contrary to what some may tell you, extreme amounts of ingenuity and overzealous creativity in choosing a topic WON’T earn you high marks in your Physics IA. In fact, choosing a topic beyond your ability, means, or equipment, may sacrifice marks in your exploration, analysis, and evaluation components (combined 18/24 of your marks, or 75%). What the IB is looking for is an effective methodology to achieve your aim, and a detailed analysis of your results, both of which will be discussed later. When looking for a topic, I recommend searching for prescribed practicals at university/college level physics courses, other high scoring physics IAs (available at IB Solved), or interesting experiments you’ve seen conducted online. This has multiple advantages – first of all, it lets you know that the experiment can be done with high school/undergraduate level materials. Second of all, it can provide a guide into constructing an effective methodology.

Main takeaway – Don’t be too original in your topic selection. Go for something tried and tested.

Criterion A: Personal Engagement (2 marks)

This is a relatively minor aspect of your IA, however it still constitutes almost 10% of your mark (2/24). According to the IB subject reports, personal engagement is best demonstrated thorough your methodology, the extensiveness of your data collection and the detail of your analysis. DON’T put a section at the beginning of your IA titled personal engagement, and DON’T make up a complex story about why you’re supposedly interested in the topic. A small introduction detailing genuine interest and the thought process that led to your experiment idea is great, however this should not last for more than than a few lines.

Main takeaway – Don’t label a section ‘Personal Engagement’ and fabricate a story, instead be honest and concise with your reasoning for choosing the topic.

Criterion B: Exploration (6 marks)

To attain full marks in this area, I recommend writing a small abstract at the beginning of your IA (the first thing the marker reads), detailing the independent and dependent variable, a brief overview of methodology, and your results. Whilst it may feel strange writing your results on the first page, a scientific report isn’t a mystery novel! Your marker isn’t waiting to be surprised by the results at the end, they prefer to have everything laid out to them in the beginning, so they can follow your report easily. An abstract should be no longer than one paragraph of 3-4 lines.

Next is your introduction. This is the place to lay out any personal engagement details, along with the line of thought that lead you to choose this topic. At the end of your introduction, you should state your fully focused research question, usually in the format: “What is the relationship between (independent variable) and (dependent variable).”

Following the introduction is your background information. This is where you build from the ground up – identify all physics laws, forces, equations, and theories of relevance to your IA. You may reference external sources for material that goes beyond your IA. At the end of this should be your hypothesis, which should logically follow from your background research.

Next is your methodology section. Essential elements in methodology include: an apparatus list, with specific lengths, masses, or dimensions of equipment; a precise methodology, which details everything you’ve done in your IA; a photo of your experimental set up; a labelled scientific diagram of your experimental set up; an identification of variables, including the dependent, independent, and controlled variables; and a controlled variables table, which lists the variable, why it needs to be controlled, and how you’re controlling it.

Main takeaway: Essential elements for Exploration include an abstract, introduction, statement of research question, background information, hypothesis, and methodology.

Criterion C: Analysis (6 marks)

This is perhaps the most important element of your IA. It is essential to have enough data to perform an effective analysis – you should have at the very least three trials (ideally five or more) for each increment of the independent variable, with at least five (ideally seven or more) different increments of your independent variable. Of course, you do not have to show all of these if it would take up too much space in your IA. If this is the case, show a few sample results and analysis at different increments, and clearly state that this process was repeated for other results. Whilst the marking scheme indicates a need for both qualitative and quantitative analysis, a Physics IA should be more weighted towards quantitative analysis, with qualitative discussion limited to explaining any adjustments needing to be made to your analysis, or unexpected results.

Also, ensure to keep in mind the accuracy to which data must be recorded. This is usually determined by the configuration of your equipment. You must also take into account human error – if you quote the result of a stopwatch to the closest millisecond with no error, you will almost certainly be penalised marks. This is where uncertainty analysis comes in.

A thorough uncertainty analysis can be the difference between a 4 and a 6 in this criterion. Almost every source of uncertainty should be discussed, even if they turn out to be negligible in your calculations (which you are free to write in your report). Examiners will be pleased if you’ve kept this in mind, as it indicates precise thought about each and every aspect of your experiment. It is especially useful to keep in mind the propagation of uncertainties, and their rules for significant figures in uncertainties, which can be found at the beginning of any IB Physics textbook. Again, if there is not enough room to show all propagation calculations, show a sample calculation and indicate that the same method was used for other areas. Uncertainties should always be indicated on graphs as error bars, even if they are negligible (write “uncertainties are indicated on graph but are negligible”), and lines of best and worst fit should be drawn.

I chose to state my conclusion after my discussion and evaluation, however this is a personal preference and different teachers prescribe different structures. Wherever it is placed, the conclusion should be a concise statement, as an answer to your research question, and either a confirmation or rejection of your hypothesis. For example: “The data suggests that there is a positive/negative proportional/power relationship between independent variable and dependent variable, which supports/contradicts the background theory which informed my hypothesis.”

Main takeaway: Your analysis should have sufficient data, a thorough consideration and discussion of the origins and propagation of all uncertainties and should be followed by a concise conclusion in response to your research question.

Criterion D: Evaluation (6 marks)

Your evaluation mark is closely related to your analysis mark. If you have discussed the origins and propagation of uncertainties throughout the analysis of results, you will already be scoring highly in this area. To finish and secure maximum marks, you should reiterate the sources of error and distinguish between random error and systematic error, with an acknowledgement of how each may be eliminated or minimised through methodological adaptation or increased trials. More advanced students may want to discuss the distribution of error, and whether it follows an approximately normal distribution or if it is skewed towards the centre or to either tails, however this would be an optional extension rather than a necessity.

You should also discuss the validity of your experiment, which is determined by how well you controlled your variables. In other words, you need to show that any changes in your dependent variable were solely caused by changes in the independent variable, solidifying the causal link between the two. A discussion of accuracy should also be included, however this should be much shorter than the discussion of validity.

Following this, you should discuss any possible changes or extensions to your methodology. These should not be too ambitious (using a high-powered microscope to measure the distance travelled by a projectile), but be informed by what you found problematic or difficult in conducting your IA. Don’t pretend that everything was perfect the first time around – it certainly wasn’t for me, and rarely ever is. Rather, discuss the difficulties you had and what you would do to overcome them in the future. These are often related to your sources of error, and should therefore be separated into improvements targeting random or systematic sources of error.

Main takeaway: Once again, be conscious of errors and uncertainties, explore the validity and accuracy of your results, and target realistic improvements related to your sources of random and systematic error.

Criterion E: Communication (4 marks)

Whilst this criterion is only worth 4 marks, and lucid and easy to read IA will allow your examiners to more easily see the thoroughness of your exploration, analysis, and evaluation. A clear structure (outlined in previous sections), is a must, while there are a few miscellaneous pointers I would suggest:

  • An abstract is especially important to examiners when judging this criterion.

  • Write the research question of your exploration on the header of each page, so the examiner doesn’t forget and have to flick back.

  • Put some colour into your graphs and tables – make the report visually attractive to read.

  • Start each new section with a fresh page.

  • Label each of your figures/tables/diagrams with a number and reference this number in your discussion.

  • Use different colours for your line of best fit and lines of worst fit, so that they’re easily distinguishable.

  • Do not exceed the word/page limit.

Give your IA to both people with a physics background (your teacher, past students, tutors) and people with no clue about physics, perhaps your family or friends. If everybody is able to follow the flow of your IA, even if they don’t understand the physics, then you’re on track for a 4/4 in the Communication criterion.

And that’s it! If you have any questions about the strategies discussed in this blog post or any of our other products and services, feel free to email

Author: Nicholas Testa (45/45) – Dux of Trinity Grammar School and Head Tutor at IB Solved.

To purchase the 24/24 Physics IA which inspired this guide, follow the link below:

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