Sometimes, it’s the little things that can prove difficult. When writing your IB Biology Internal Assessment write-up, you’ll need to be sure that the more straight forward elements of the IA don’t trip you up. With so many components and the requirements for high-level detailed analysis, it is easy to get distracted by the more complicated parts of your IA and neglect to give the simpler sections the attention they require.
This article was taken from the last edition of the student guide Biology Internal Assessment SL & HL written by Ashby Merson-Davies, for students taking Diploma final exams up to 2024. It aims to help you avoid this pitfall when it comes to presenting your method in your IB Biology IA write-up. The advice is all generally relevant to Biology students taking final exams from 2025, but we are checking and updating this article for any relevant updates in advance of publishing our new edition of the Biology Internal Assessment guide.
Presenting your IB Biology IA Method
Before a scientific paper is published it goes for peer review. This allows other scientists to repeat the investigations to see if they get the same results. This is a very important scientific process so it is essential that the method used is described clearly and precisely. The same applies to your description – simply imagine you are giving your instructions to a classmate who will do the investigation for you.
Key points:
- It can be written as a set of instructions or more personally. For example:
- Instruction: Use a 10 cm3 syringe to add 8 cm3 to the boiling tube labelled 1.
- Personal: I added 8 cm3 to the boiling tube labelled 1 using a 10 cm3 syringe.
- It must follow the correct sequence of steps (e.g. do not say ‘I fitted the bung to the boiling tube but first I added the methylene blue’)
- Ensure all the controlled variables you listed are controlled and how they are controlled.
- Ensure they are controlled in an appropriate and precise way. This is where the correct choice of apparatus and material is important.
- State precisely all measurements, timings, an equipment that was use.
- Remember to allow for anomalous data. For example, if a particular statistical analysis needs 15 sets of data, aim to collect 18.
- Aim to have sufficient replicates for your statistical analysis.
- Have sufficient apparatus to prevent cross contamination. If this is not possible then describe how you prevented cross contamination (e.g. The syringes were washed in distilled water and dried.)
- Take care not to give inappropriate descriptions (e.g. ‘I controlled the temperature with a thermometer’). A thermometer can only measure temperature, not control it.
- ‘Amount’ is an often misused word so avoid using it. For example, ‘Collect the same amount of leaves’. This could mean mass or number; so state as follows: ‘Collect the same number of leaves’.
- Avoid writing the Method as a continuous prose style essay as it is difficult to follow the steps. Break it up into paragraphs, each of which describes a particular step.
Example of a poor presentation of an IB Biology IA Method
Example of a good presentation of an IB Biology IA Method
