Criterion A evaluates the clarity, focus, and appropriateness of your research question, variables, and methodology. It examines how well your experiment is structured to test the research question scientifically and effectively.
Marks | Descriptor |
0 | The report does not reach the standard described by the descriptors below. |
1-2 | The research question is stated without context.
Methodological considerations associated with collecting data relevant to the research question are stated.
The description of the methodology for collecting or selecting data lacks the detail to allow for the investigation to be reproduced. |
3-4 | The research question is outlined within a broad context.
Methodological considerations associated with collecting relevant and sufficient data to answer the research question are described.
The description of the methodology for collecting or selecting data allows for the investigation to be reproduced with few ambiguities or omissions. |
5-6 | The research question is described within a specific and appropriate context.
Methodological considerations associated with collecting relevant and sufficient data to answer the research question are explained.
The description of the methodology for collecting or selecting data allows for the investigation to be reproduced. |
A thorough design of scientific investigation should be demonstrated through the contents of the Introduction and Method sections of the IA report. This includes the research question, background information, variables, material list, preliminary testing, procedure, and risk assessments.
0. Choosing the Topic
Choosing a topic and formulating a research question (RQ) are critical first steps in your IA. A well-chosen topic not only aligns with your interests but also ensures the scope is manageable within the constraints of time, resources, and IB criteria. By selecting a topic that excites you and crafting a clear, focused RQ, you can create an IA that is both scientifically rigorous and personally rewarding.
Where to Start:
1. Review Previous Lab Exercises
Start by revisiting the lab exercises conducted in class. These practical activities often introduce fundamental biological concepts and experimental techniques that can be expanded into a full IA investigation. Consider variables from past experiments that could be altered or explored in more depth.
Example:
2. Review DBQ and Experiment Sections in Textbooks
Textbooks often include Data-Based Questions (DBQs) and experimental scenarios that provide a wealth of ideas for IAs. These sections frequently highlight key biological concepts and variables that can be tested.
Look for:
3. Brainstorm Areas of Personal Interest
Think about areas of biology that fascinate you. Your IA is an opportunity to explore topics that resonate with you personally, making the process more engaging and rewarding
You might be:
Follow these 5 steps:
1.
Identify ‘Your Top 3’ interests
2.
Brainstorm variables
a.
Define the Independent Variable (IV), Dependent Variable (DV), and at least 5 Controlled Variables (CVs).
3.
Ensure that the DV can be quantitatively measured
4.
Ensure that the IV can be divided into at least 5 distinct groups
a.
Preferably measurable or quantifiable, e.g. concentrations, time intervals, temperature levels
5.
Consider practicality
a.
Evaluate the environmental, ethical, and safety implications of the experiment to ensure it is feasible and adheres to IB guidelines.
Biology Example Topics:
Physics Example Topics:
Chemistry Example Topics:
N.B Following are the restrictions in topic selection: Experiments involving human or pathogenic cell cultures, animal welfare considerations, hazardous materials or equipment, genetic modification or bioethical violations, environmental harm, and human experiments.
1. Generating A Research Question
Once you’ve identified a topic, the next step is to refine it into a focused, testable, and feasible Research Question (RQ) that meets the IB criteria and can gain approval from your teacher. This process often involves thorough research to explore how similar topics or experimental setups have been studied by other scientists, providing a foundation for your own investigation.
A strong RQ should:
1.
Clearly identify the independent variable (IV) and dependent variable (DV) that are measurable, with appropriate units.
2.
Include a minimum of five distinct conditions for the IV to be tested.
3.
Be specific about the system being studied (e.g., the model species, the experimental setup used, or the measurement conditions).
Example Progression with the Broad topic of ‘Photosynthesis’
1.
Identified “light intensity” as another factor that affects the rate of photosynthesis, from a DBQ in the textbook investigating the effect of the duration of sunlight exposure on photosynthesis. The data shown involved monitoring photosynthesis by measuring the volume of oxygen gas produced by an aquatic plant species.
Initial RQ (4/6 points): “How does the light intensity affect the rate of photosynthesis, measured by the volume of oxygen produced by an aquatic plant?”
2.
Researched online the detailed conditions that need to be determined to set up an experiment.
“Through research, I found that the brightness of a brightly lit office room has an intensity of approximately 500 lux. Therefore, I decided to make the range of my IV between 0-500 lux.”
“I researched how the rate of photosynthesis can be measured and found out that measuring the volume of oxygen gas (cm3) given off by an aquatic plant Elodea is a common experimental approach.”
Refined RQ (6/6 points): “How does light intensity (0, 100, 200, 300, 400, 500 lux) affect the rate of photosynthesis in Elodea canadensis, measured by the volume of oxygen produced (cm³/min) using a gas syringe during 20 minutes of incubation at room temperature?”
Biology Example
Physics Example
Chemistry Example
2. Crafting a Research Proposal
The Research Proposal outlines your IA topic, research question (RQ), and the materials and equipment required for your investigation. This allows the school to make necessary purchases or preparations in advance. If your topic overlaps with a classmate’s, your teacher may assign you to a group to collaborate on performing the experiment and sharing a common data set. However, each student must formulate a unique RQ with a distinct focus and conduct an independent analysis to meet IB criteria.
a. Proposal Template
The level of detail required in your proposal may vary depending on your teacher or school. At a minimum, your proposal must include two essential components: a Research Question (RQ) and a detailed Material List. Additionally, some teachers may ask for further details, such as your variables and an outline of the experimental procedure. A standard proposal typically includes the following key components:
1.
Research Question
•
Clearly state your focused and measurable research question.
2.
Background Context
•
Provide a brief explanation of the biological concept behind your question, especially any details or principles not explicitly covered in the IB Biology syllabus
3.
Variables
•
Independent Variable (IV): What you will change in the experiment, with clearly defined groups or conditions that will be varied.
•
Dependent Variable (DV): What you will measure (e.g., rate of photosynthesis, measured by the volume of oxygen gas collected in a gas syringe over a 20-minute duration).
•
Controlled Variables: List at least five key controls.
4.
Material List
•
Include a full list of chemicals and equipment that are needed, including the quantity and specification on size. (e.g., 50g of glucose, 10g of yeast powder, five 200ml beakers, etc.)
5.
Methodology Overview
•
Briefly outline your experimental design and methods.
Example of a proposal template:
b. Common Reasons for Rejection and How to Avoid Them
1.
Vague Research Questions
Rejected | Improved |
"How does light affect photosynthesis?" — this research question is too broad and vague. | "How does light intensity affect the rate of photosynthesis in Elodea canadensis, measured as the volume of oxygen produced?" — this research question specifies what aspect of light will be investigated and how the results will be measured. |
Problem: Broad or ambiguous questions that lack clear variables. | Fix: Narrow your focus to one IV and one measurable DV. |
2. Overly Complex or Unrealistic Methods
Rejected | Improved |
"Investigating how UV intensity affects melanin production" — this is unrealistic because it requires human skin cell lines and specialized equipment like clean benches, which are not available in most high school labs. | “How the duration of UV exposure affects E coli. Growth.” — this is a more realistic experiment that can be conducted in school laboratories. |
Problem: Experiments that require inaccessible equipment, specialized resources, or excessive time. | Fix: Simplify your design. Choose a feasible, straightforward experiment that can be conducted within your school’s resources and time constraints. |
3.
No Link to the Biology Syllabus
Rejected | Improved |
"Investigating the effect of Vitamin C on the solubility of iron supplements"— this aligns with Chemistry, not Biology. | "How does the concentration of Vitamin C affect the growth rate of yeast or E. coli?"— this links to Biology concepts such as cellular growth and metabolism. |
Problem: Topics unrelated to IB Biology core concepts are dismissed | Fix: Select a topic that aligns directly with syllabus content, such as enzymes, photosynthesis, osmosis, or cell respiration |
3. Designing your Experiment
Once your topic is approved, finalize your research question (RQ). While drafting the Background information, Variables, Materials, Procedures, and Data Collection plan, continuously evaluate the feasibility of executing the experiment. Make adjustments to your RQ or methodology as needed to ensure practicality and alignment with your resources.
a. Background Information
The Background Information section provides the scientific context needed to understand the experiment and its relevance. It explains key concepts, processes, and theories that underpin the research question (RQ) and helps justify the investigation. Here's what should be included:
1.
Introduction to the Topic
•
Provide a brief overview of the biological topic or concept that your IA investigates.
2.
Scientific Concepts and Theories
•
Explain the biological principles related to your experiment, ensuring the reader understands the foundational science behind your RQ.
•
Focus on relevant information specific to your research topic, particularly details that extend beyond the standard IB Biology syllabus.
•
Highlight relevant processes, pathways, or systems involved in your experiment.
•
Example: “Iron plays a key role in chlorophyll synthesis by facilitating the availability of protoporphyrin IX and supporting electron transport in photosynthetic pathways, indirectly promoting chlorophyll production and photosynthesis.”
3.
Justification of Variables
•
Introduce the independent variable (IV) and dependent variable (DV) and explain their biological relevance.
•
Provide reasoning for selecting these variables and their connection to the research question.
•
Example: “Iron is an essential cofactor in chlorophyll synthesis, and its availability may directly influence photosynthetic rates in Elodea canadensis.”
4.
Previous Research or Scientific Literature
•
Summarize any relevant studies, findings, or experimental results that provide a foundation for your investigation.
•
Use credible sources such as scientific articles, textbooks, or peer-reviewed journals to support your experimental design.
•
Example: “Studies have shown that micronutrient availability, such as magnesium or iron, impacts chlorophyll synthesis and, consequently, photosynthetic efficiency in aquatic plants. However, the specific relationship between iron concentration and photosynthetic rates remains less understood.”
5.
Hypothesis (Optional)
•
If applicable, state your hypothesis and briefly explain the reasoning behind it based on the background information.
•
Example: “It is hypothesized that increasing iron concentrations will enhance the rate of photosynthesis in Elodea canadensis up to an optimal point, after which chlorophyll synthesis and photosynthetic efficiency will plateau.”
b. Variables
Independent Variable (IV): What will be changed in the experiment
Example | Developed | Justified |
Light intensity | Light intensity of 0 (No light), 100, 200, 300, 400, and 500 lux using an LED lamp 30 cm away from the plant. | The light intensity range of 0-500 lux was chosen because typical indoor light conditions, such as a well-lit office, measure approximately 500 lux. |
Dependent Variable (DV): What will be qualitatively measured in the experiment
Example | Measurement | Justification |
Rate of oxygen production | A gas syringe will be used to measure oxygen production in mL/min | The measurement of the volume of oxygen procured serves as an indirect measure of the rate of photosynthesis because oxygen is a byproduct of the light-dependent reactions. |
Controlled Variable: Factors other than the IV that can affect DV
Example | How it affects DV | How it should be controlled |
Temperature | The rate of photosynthesis increases with an increase in temperature due to increased collision between enzymes and substrates involved in the metabolic process. If the temperature is too high, enzymes involved in photosynthesis may denature, decreasing the rate. | Temperature will be maintained at 25°C using a water bath. A thermometer will be placed inside the beaker to ensure that the temperature stays within ±1°C of 25°C. |
* Keep in mind that there often multiple controlled variables, such as the distance of LED light, concentration of sodium bicarbonate, the mass and size of Elodea in each trial, and the duration of light exposure for this experiment.
Command: Acknowledge variables that cannot be controlled in your evaluation and discuss its potential impact.
c. Methodology - Material List, Procedure and Feasibility
The methodology section should include a comprehensive materials list, a clear and detailed procedure, and an assessment of potential risks to ensure your experiment is replicable, safe, and scientifically rigorous.
Materials and Equipment List:
•
Provide a detailed list of all materials and equipment used in the experiment.
•
Include specifications such as sizes, volumes, and measurement uncertainties (e.g., "10 mL graduated cylinder, ±0.1 mL").
•
Use a table format for clarity if there are multiple items.
Example Materials List for Biology:
Example Materials List for Physics:
Example Materials List for Chemistry:
Tip: Request a surplus of materials to account for 1-2 preliminary trials and any potential failures during the experiment.
Command: Include uncertainties for measurement equipment and tools.
Procedure:
•
Write a step-by-step description of your experimental process.
•
Ensure the steps are detailed and precise to allow for exact replication of the experiment.
•
Mention the number of trials or replicates to improve reliability.
Feasibility:
•
Command: Design an experiment you can realistically conduct using school lab equipment and within the time frame available.
•
Checklist for Feasibility:
1.
Does your experiment require specialized equipment? If so, can you access it?
2.
Can you collect sufficient data in the time available?
3.
Are your IV increments practical? Avoid extremes that may be impossible to measure.
Sample Procedures:
d. Safety, Environmental, and Ethical Considerations
•
Identify potential risks associated with your experiment and outline the steps to mitigate them.
•
Include safety measures such as wearing appropriate protective gear, careful handling of chemicals, and proper waste disposal methods.
•
Address any environmental considerations and describe how these are accounted for in your experimental method.
•
Follow IB guidelines to ensure your experiment is ethical:
◦
Avoid harm to living organisms (e.g., animals, including humans).
◦
Use humane and minimal-impact methods.
◦
Obtain informed consent if human participants are involved.
Example:
Biology
Category | Consideration |
Safety | Sodium bicarbonate solution can irritate the skin or eyes upon contact. Wear gloves and goggles while handling the solution, and wash hands immediately after contact. Broken glassware can cause injuries, so inspect for cracks before use and handle carefully. Clean broken glass with a dustpan and brush. Overheating of the LED lamp can cause burns; allow the lamp to cool between trials and ensure proper ventilation. Spilled water can create a slipping hazard, so wipe up any spills immediately to maintain a dry work area. |
Environmental | Sodium bicarbonate solution can alter the pH of water systems if disposed of improperly. Dilute or neutralize the solution as per local guidelines before disposal. Use only the minimum number of Elodea canadensis samples required to minimize environmental impact. Return unused samples to their natural habitat (if permitted) or dispose of them responsibly in organic waste. |
Ethical | The experiment involves the use of living organisms (Elodea canadensis). Handle the plants with care to avoid unnecessary harm. Plan the experiment carefully to use only the amount of Elodea needed to achieve reliable results, avoiding excessive replication or waste. |