Introduction
Choosing an experiment for your science Internal Assessment (IA) is one of the most important decisions you’ll make. A strong IA experiment should be feasible with the resources you have, original enough to stand out, and structured in a way that allows for analysis and evaluation. Many students struggle because they pick experiments that are either too complex to manage or too simple to earn top marks.
In this guide, we’ll break down how to select an IA experiment that is both manageable and original. We’ll also look at common pitfalls and show you how to refine your idea into something examiners will reward. For real examples of successful IA experiments, explore RevisionDojo’s coursework exemplars.
Quick Start Checklist: Choosing Your IA Experiment
- Is it safe and ethical?
- Can it be done with available resources?
- Does it allow for multiple trials?
- Is the research question focused and specific?
- Does it offer opportunities for analysis and evaluation?
Step 1: Start With Your Interests
The best IA experiments often come from genuine curiosity. If you’re interested in sports, nutrition, or the environment, start there. For example:
- Testing how different sports drinks affect heart rate recovery
- Investigating how soil pH affects plant growth
- Measuring how insulation materials reduce heat loss
Examiners appreciate IAs that reflect personal interest — it makes your work more engaging.
Step 2: Keep It Manageable
Many students overreach and choose experiments that are too complex. The IA is not a PhD thesis — it should be something you can realistically complete in your school lab or at home with supervision.
Manageable experiments:
- Require equipment you already have access to
- Can be completed within a few weeks
- Allow for at least 3–5 trials for reliability
Unmanageable experiments often require advanced lab equipment, rare materials, or months of data collection — avoid these.
Step 3: Make It Original
Original doesn’t mean brand-new science. It means giving your IA a personal twist. For example:
- Instead of “How does temperature affect enzyme activity?” try “How does the temperature of dish soap solutions affect the activity of catalase in potato extracts?”
- Instead of “How does light affect plants?” try “How does blue LED light affect the growth rate of basil compared to red LED light?”
These small adjustments make your IA unique while keeping it feasible.
Step 4: Focus on Variables
A strong IA experiment has a clear independent and dependent variable, with controlled conditions.
Example:
- Independent variable: Concentration of caffeine solution
- Dependent variable: Heart rate of Daphnia
- Controlled variables: Temperature, light exposure, water conditions
This clarity helps examiners see the strength of your experimental design.
Step 5: Think About Evaluation Early
When planning your IA experiment, consider what limitations you might face and how you could improve the design. Examiners want to see that you can evaluate your methods critically.
For example:
“While measuring plant height was effective, using leaf surface area would have provided more precise data.”
By thinking ahead, you’ll naturally build evaluation into your IA.
Common Mistakes When Choosing IA Experiments
- Too broad: Trying to answer a question that needs professional labs.
- Too simple: Choosing an experiment that doesn’t allow for analysis.
- Unsafe: Selecting experiments with harmful chemicals or ethical issues.
- Unrealistic: Planning an IA that can’t be completed within school timelines.
Examples of Manageable and Original IA Experiments
- Biology IA: “How does sugar concentration affect the rate of yeast fermentation?”
- Chemistry IA: “How does the concentration of salt solution affect the rate of corrosion in iron nails?”
- Physics IA: “How does changing the angle of a ramp affect the velocity of a rolling ball?”
- Environmental Systems IA: “How do different natural fertilizers affect the growth of bean plants?”
Each is specific, safe, and achievable within an IB school setting.
Why Exemplars Are Useful
If you’re unsure whether your IA experiment idea is strong enough, reviewing successful models is the best way to decide. RevisionDojo’s coursework exemplars include science IAs with focused, original, and well-structured experiments that scored highly.
FAQs on IA Experiments
1. Do I need to design a completely new experiment?
No — originality can come from modifying a common experiment, applying it to a new context, or adjusting variables.
2. How do I know if my IA experiment is too simple?
If your experiment only produces descriptive results without room for analysis or evaluation, it’s too simple.
3. How many trials should I run in my IA experiment?
At least 3–5 trials are recommended for reliability. More trials strengthen your evaluation.
4. Can I do my IA experiment at home?
Yes, if it’s safe, ethical, and approved by your teacher. Many great IAs come from simple home-based experiments.
5. Where can I see examples of successful IA experiments?
The best place is RevisionDojo’s coursework exemplars, which feature high-scoring science IAs across multiple disciplines.
Conclusion
Choosing an IA experiment that is both manageable and original is the foundation of a successful Internal Assessment. By focusing on your interests, narrowing your variables, keeping the experiment feasible, and planning for evaluation, you’ll create a project that examiners reward. For real inspiration, study RevisionDojo’s coursework exemplars, where top IB students showcase their best IA experiments.
Call to Action
Ready to design your IA experiment? Explore RevisionDojo’s coursework exemplars today and learn how high-scoring students balanced originality with feasibility.
