The introduction is one of the most misunderstood parts of the IB Physics Scientific Investigation. Most students either write three paragraphs about how much they love the topic (examiner: unmoved) or cram in every piece of background theory they know (examiner: also unmoved).
What examiners actually want is simple, specific, and very achievable. This post gives you a 5-step blueprint, three excellent examples to model, and three bad ones so you can see exactly where things go wrong.
If you still need a research question, start with my 100 IB Physics IA ideas first, then come back here once you have one.
The One Thing That Annoys IB Examiners Most
Before the blueprint, let’s get this out of the way.
The May 2022 IB Physics Examiner Subject Report was very direct on this point. The examiners specifically flagged two things they do not want to see:
- Do NOT write a section (or paragraph) with the heading “Personal Engagement”
- Do NOT include artificial comments of interest in your research question
The examiner does not want to be told you are fascinated, amazed, or passionate. They want to see it through the quality of your work.
If your introduction contains “I have always been fascinated by…” or “This topic amazes me because…” — cut it. Those phrases actively work against you.
The 5-Step Blueprint
Use this for every introduction you write. The target is around 150 words.
Step 1: State your research question clearly
Your very first sentence should be your research question (or a restatement of it). This focuses the examiner immediately and tells them what they are about to read.
A strong research question has one independent variable and one measurable dependent variable. For example:
How does the angle of incidence affect the power output of a photovoltaic cell?
Step 2: Give a brief overview of your method
One to two sentences. What did you do, and how? You are not writing the full method here — just enough context for the examiner to understand the shape of the investigation.
Example: This investigation used a solar simulator to measure the power output of a photovoltaic cell at different angles of incidence.
Step 3: Summarise your result
Yes — in the introduction. One sentence. This is not “spoiling” your report. It shows the examiner you understood what you found and can communicate it clearly.
Example: Results showed a decrease in power output as the angle of incidence increased, due to less intense light absorption and increased surface reflection.
Step 4: Give real-world context
Why does this research question matter? One or two sentences connecting your investigation to the wider world. This is where subject knowledge earns its place — not in a long background theory section, but in a brief, purposeful statement of relevance.
Example: Optimising photovoltaic cell performance is important for reducing the cost of solar energy systems and increasing their adoption as a sustainable energy source.
Step 5: Show personal engagement — briefly
One sentence. Genuine, specific, not gushing. Connect the topic to something real about you: a place you have been, something you observed, a news story, a personal interest. Keep it to one sentence and keep the language calm.
Example: As a student with an interest in sustainable energy, I was eager to explore the physics behind photovoltaic efficiency experimentally.
Putting It Together
Here is the full introduction built from those five steps:
This investigation aims to determine the effect of the angle of incidence of direct sunlight on the power output of a photovoltaic cell using a solar simulator. Results showed a decrease in power output as the angle of incidence increased, due to less intense and less effectively absorbed light and increased reflection off the cell surface. Optimising photovoltaic cell performance is important as it can reduce the cost of photovoltaic systems and promote their adoption as a sustainable energy source. As a student with an interest in sustainable energy, I was eager to experimentally explore the physics behind the efficiency of photovoltaic cells.
(100 words)
Check it against the list:
- Research question is clear ☑
- Method is described ☑
- Result is summarised ☑
- Real-world relevance is given ☑
- Personal engagement is present (one sentence, no waffle) ☑
- Under 150 words ☑
3 Excellent Introduction Examples
Example 1: Bridge deflection
Research question: How does the length of a bridge affect the sag when a constant mass is applied to the centre?
Introduction:
This investigation aims to model and determine the relationship between the length of a bridge and the deflection that occurs when a constant weight is placed at its centre. Various lengths of a model bridge were tested under constant weight and the results showed that deflection is directly proportional to the cubed length of the bridge. Understanding how a bridge’s length affects its structural integrity is crucial in the design of safe infrastructure. I recently visited San Francisco, home to the Golden Gate Bridge and the Bay Bridge, and found myself thinking about the physics that keeps those structures stable under load. I was eager to explore this in a school laboratory setting. (112 words)
Why it works: clear research question, concise method, result stated upfront, genuine real-world context, one specific personal connection.
Example 2: Electromagnetic damping of a pendulum
Research question: How does the strength of a magnetic field affect the period of oscillation of a pendulum?
Introduction:
This investigation aims to determine the effect of magnetic field strength on the period of oscillation of a pendulum. The period was measured across different magnetic field strengths using a stopwatch and electromagnet, with results showing that the period of oscillation is directly proportional to the square of the voltage applied to the electromagnet. The principles of electromagnetic damping are applied in maglev trains, seismometers and accelerometers. I live in China, where prototype maglev trains capable of 620 km/h are currently in development. I wanted to explore electromagnetic effects on a pendulum to better understand the physics behind this technology. (107 words)
Why it works: specific research question, method and result in two sentences, real-world relevance tied to current technology, personal connection that is genuine rather than generic.
Example 3: Terminal velocity of a toy parachute
Research question: How does the mass of a toy parachute affect its terminal velocity during free fall?
Introduction:
This investigation aims to determine the effect of the mass of a toy parachute on its terminal velocity during free fall. The terminal velocity for each trial was calculated by measuring the time taken to fall a fixed distance, with results showing that mass is directly proportional to the square of terminal velocity. This has real-world applications in skydiving and aeronautics, where understanding the relationship between load and descent speed is critical for safety. As a student interested in the physics of flight and air resistance, I was keen to investigate this relationship experimentally. (94 words)
Why it works: everything is there in under 100 words. Tight and clean.
3 Bad Introduction Examples
These are the patterns examiners flag most often. Read them carefully.
Bad Example 1: All context, no content
Research question: How does the length of a bridge affect the sag when a constant mass is applied?
Introduction:
I have decided on the topic of architecture because it involves mechanics and is a combination of multiple subjects, such as physics, history, mathematics, and art. Since I have travelled to a lot of places around San Francisco, noticing different kinds of human structures, I became curious about how they work. Also during the summer holiday I went on a drawing architecture course which mainly focused on the drawing aspect of architecture and I began questioning what forces affect structures. This made me more curious about bridges.
Why it fails:
- Research question is not stated ✗
- Method is not described ✗
- Result is not mentioned ✗
- Grammar and spelling errors ✗
- Personal engagement is present but buried in waffle ✗
Bad Example 2: Great voice, wrong focus
Research question: How does the strength of a magnetic field affect the period of oscillation of a pendulum?
Introduction:
Watching a high-speed train momentarily pause the fight between Black Panther and Killmonger, I could not help but wonder about the mechanisms involved in its motion. A quick search led me to electromagnetic induction and eddy current braking. This device slows a moving object by dissipating kinetic energy as heat. The drag force is an electromagnetic force between a magnet and a nearby conductive object due to eddy currents induced through electromagnetic induction. Fascinated by this phenomenon and having an understanding through my physics class, I sought to investigate magnetic braking using a simple pendulum.
Why it fails:
- Research question is not stated ✗
- Method is not described ✗
- Result is not mentioned ✗
- Word “fascinated” flags immediately as artificial engagement ✗
- The opening is entertaining but tells the examiner nothing about the investigation ✗
Bad Example 3: Personal engagement without substance
Research question: How does the mass of a toy parachute affect its terminal velocity during free fall?
Introduction:
When I was young, I was fascinated with toy parachutes. I would throw them out my bedroom window and add different toys to them. I now want to join the national Air Force, specifically the parachute division. In my research to reach my career goal, I began reading articles about the effects of mass on terminal velocity and as a student who has always been fascinated by the physics of flight, this research question caught my attention and I was excited to explore the physics behind it.
Why it fails:
- Research question is not stated ✗
- Method is not described ✗
- Result is not mentioned ✗
- “Fascinated” used twice ✗
- Personal story is disproportionate to the physics content ✗
The Pattern
Look at the three bad examples and you will see the same problem in each of them: they prioritise the story over the science. The student is the main character, not the investigation.
Flip it. Put the research question first. Put the result in sentence three. Then earn your personal engagement with one specific sentence at the end.
That structure is what the examiner is looking for, and it is what gets marks.
For the full structure of every section in your report, including exactly what to include in your Variables, Raw Data and Evaluation sections, read the complete IB Physics IA structure guide. If you are earlier in the process and still working out your research question or experimental design, the complete Scientific Investigation guide covers everything from start to finish.
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Sally Weatherly is a Fellow of the Institute of Physics, author of 4 IB Physics books (two hit #1 on Amazon), and has been teaching IB Physics since 2004. GradePod has helped 30,000+ students since 2020.