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IBDP: Extended Essay

Resources to support students as they plan, write, edit, and revise their Extended Essays

Writing an EE in Chemistry

Chemistry: Overview

  • An essay in Chemistry offers the opportunity to investigate and collect primary or secondary data, based on a focused research question. You collect evidence using scientific methodology. Your findings must lead to a valid, evidence-based conclusion.
  • Science essays can be characterized by the development of hypotheses, replicable data and the use of peer-reviewed publications. These three processes differentiate a scientific process from a pseudoscientific one.
  • A good extended essay is based on accepted, subject-specific methodology, requires a good understanding of the underlying concepts and uses appropriate terminology. Science extended essays based on primary data must use controlled, independent variables and a standardized methodology that makes the research applicable and allows valid conclusions to be drawn.

Requirements for a Chemistry EE

The Subject-Specific Guidance page for your chosen subject is THE KEY to ensuring your paper meets the requirements. Print, highlight, and annotate this page and pin it above your desk!

The Command Terms are the key terms and phrases used in examination questions. Using these in your essay will indicate a strong background in your subject

The Subject Reports give an overview of what EXAMINERS have said about makes a successful paper in the subject. It's smart to read these over to know what the examiners are looking for.

Your Step-by-Step Guide to Researching and Writing a Science EE

Think of your Extended Essay as a scientific detective story. You're investigating a question, gathering clues (data), and reaching an evidence-based conclusion.


๐Ÿ” Step 1: The Detective Work (Background Research)

  • Do Your Homework First: Before you do anything else, you need to become an expert on the basic science behind your topic. This is true for everyone, whether you're doing an experiment or a literature-based essay.

  • Understand the Concepts: Use textbooks and reliable websites to fully grasp the theories and concepts. You can't analyze advanced research if you don't understand the basics.

  • Choose Good Sources: When you move to scientific journals and articles, make sure they are credible. Explain in your essay why you chose these specific sources.


โ“ Step 2: The Case File (Your Research Question)

  • A Sharp Question is Key: Your entire essay is built around your research question. It must be focused and clear.

  • What Makes a Good Question?

    • It sets the structure for your entire essay.

    • It leads to a specific methodology (an experiment or a way to analyze data).

    • It uses the correct scientific terminology.

    • All the variables in your question must be things you can clearly define and measure.

    • Remember: You must use metric units (The International System of Units - SI)!


๐Ÿงช Step 3: The Plan (Methodology)

  • Write a Recipe: Your method should be so clear and detailed that another student could read it and repeat your investigation exactly.

  • Be Scientific: Your plan must show that you are controlling variables and measuring things in a standardized, fair way.


๐Ÿ“Š Step 4: The Evidence (Presenting Your Results)

  • Be Clear and Organized: Present your data in tables, graphs, or diagrams. Everything must be clearly labeled with titles, units, and numbers so it's easy to understand.

  • For Secondary Research: It's okay to use graphs from other sources, but you must do your own analysis of that data. You can't just copy their conclusions.


๐Ÿง  Step 5: The Verdict (Discussion & Conclusion)

  • What Does It All Mean? This is where you explain the significance of your results. Do they answer your research question?

  • "Negative" Results are Still Results! If your data does NOT support your original hypothesis, that is perfectly fine! A honest analysis of unexpected results often makes for a more interesting and sophisticated essay.

  • Support Your Claims: Your conclusions must be directly backed up by the data you presented.


โš–๏ธ Step 6: The Review (Evaluation)

  • Be Your Own Biggest Critic: This is where you show you're a true scientist. You must critically evaluate your own work.

  • Ask Yourself:

    • How did my methodology affect my results? Was it a good way to answer my question?

    • What were the limitations? (e.g., small sample size, imperfect equipment, time constraints)

    • How could this investigation be improved in the future?

    • What new questions did my research uncover?

The Golden Rule

Your EE is a journey of scientific inquiry. It's not about proving you were right from the start. It's about showing you can ask a meaningful question, follow a rigorous process, and think critically about your findings, whatever they may be.

Sample Research Questions

Review the questions below

  • Which ones will be most successful?
  • What ideas do the questions spark for you?

 

Topic: The effect of manganese oxide versus copper (II) oxide in the catalysation of hydrogen peroxide

Research question: What is the effect of manganese oxide versus copper (II) oxide in the catalysation of hydrogen peroxide at 21หšC?

Outline of Approach: Begin by gathering background information regarding decomposition of hydrogen peroxide and different catalytic pathways and mechanisms.

Practical research is undertaken with careful selection of variables.

Comparative graphs are produced showing the results and interpreting them using theory.

 

Topic: The electronegativity of the distinctive atom in inorganic mono-oxoacids

Research question: How does the electronegativity of the distinctive atom in inorganic mono-oxoacids affect its pKa values?

Outline of Approach: This can be typical data-based research.

The background information initially gathered should consider appropriate acid-base theory, the definition of pKa and the inductive effect.

Several sources must be used to determine values for dependent and independent variables.

The results are shown in a graph that can be analysed using the main theoretical issues.

 

Chemistry Questions, scoring A or B

  • To what extent does the density of heptadacafluro 1 decanethiol nanostructures on a nano roughened silver surface affect it superhydrophobicity? 

  • To what extent does the use of a Lucky Iron Fish increase the iron content of water? 

  • How does a differing volume of hexane-1,6-diol or 1,6-hexamethylene diisocyanate impact the insulation property of Sika Boom® polyurethane foam? 

 

Other Questions (score unknown)

  • How does the addition of salt (NaCl) which modifies the salinity affects the interfacial tension and stability of oil-in-water emulsion?

Past Papers: Why Read Them?

  • See common structures, methodologies, use of command terms and other subject-specific vocabulary
  • Notice the difference between successful papers AND papers that were less successful
  • Read the examiner comments on scored papers and their reflections to note what worked and what didn't

 

Chemistry Papers

Example 1: Extraction of β-carotene

Research question: What is the effect of temperature on the concentration of β-carotene extracted when orange peel powder is heated with ethanol under reflux for a retention time of 10 minutes?

Example 2: Chemiluminescence of luminol

Research question: How do variations in the concentration of hydrogen peroxide affect the intensity and the longevity of the light emitted by the chemiluminescent oxidation of luminol?

Example 3: Tea polyphenol concentration

Research question: How will changing the temperature and time of the cold brewing process affect the tea polyphenol concentration in green tea water?

 

Examples from the OLD GUIDE, to be used for ideas only

Assessment of a Science Essay

Review the general assessment criteria in the  Assessment Tab first.

Then review these descriptors, specific to SCIENCE courses, to see what to focus on.

Five Criterion: Full marks = 30 points

  • A: Framework (6 marks)
  • B: Knowledge and Understanding (6 marks)
  • C: Analysis & Argument (6 marks)
  • D: Discussion & Evaluation (8 marks)
  • E: Reflection (4 marks) see Reflection tab

A: Framework for the Essay

The research question will decide the research methods, which then need to yield appropriately scientific data that supports a logical response to it. A focused question encourages strong data analysis and critical evaluation of findings.

For sciences extended essays where the research is conducted in universities or other external organizations, ensure that the methods used are your own and not just those established by the organization.

Structural conventions: essays in the sciences often include more data than other subjects, so make sure that data tables, diagrams and graphs can be clearly understood and are appropriately labelled, and that all data is clearly processed. Examples of calculations should include mathematical uncertainties on the measurements collected.

B: Knowledge and Understanding

Knowledge and understanding must be demonstrated by exploring and discussing the underlying processes and theories, using clear and well-explained terminology. This is especially critical in essays based on secondary data. For example, when investigating the turnover rate of an enzyme, it is essential to discuss enzyme kinetics.

C: Analysis and Line of Argument

Analysis must follow standard processes, including qualitative and quantitative approaches and statistical methods where appropriate, and may include mathematical transformation. The analysis should be done in such a way as to address the research question directly.

Analysis of secondary data must be your own.

A clear line of argument should be maintained throughout and all elements of your sciences extended essay should be linked; only then is it effective in communicating your message. For example, if the topic is about the kinetics of photosynthesis, then discussion of the morphology of plant leaves is not relevant.

If the research question is not fully answered, you should state unresolved issues, account for these and suggest improvements.

D: Discussion and Evaluation

The discussion should be critical, have a scientific context and must always be linked to the research question. Ensure that discussions use the sources to support conclusions.

The conclusion should not be a repetition of results but a supported, well-explained synthesis of them.

The evaluation of your essay should indicate any unresolved issues, accounting for these and suggesting improvements, and should be linked to the findings and the research question.