This criterion assesses the extent to which the student establishes the scientific context for the work, states a clear and focused research question and uses concepts and techniques appropriate to the Diploma Programme level. Where appropriate, this criterion also assesses awareness of safety, environmental, and ethical considerations.
The issue here is the overall methodology. You need to take your individual ideas and translate them into a workable method. You must also demonstrate the thinking behind your ideas using your subject knowledge. The information given must be targeted at the problem rather than being a general account of the topic matter, in order to demonstrate focus on the issues at hand.
What needs to be seen is a precise line of investigation that can be assessed using scientific protocols. It is then expected that you give the necessary details of the method in terms of variables, controls and the nature of the data that is to be generated. This data must be of sufficient quantity and treatable in an appropriate manner, so that it can generate a conclusion, in order to fulfill the criteria of analysis and evaluation. If the method devised does not lead to sufficient and appropriate data, this will lead to you being penalized in subsequent sections where this becomes the crux of the assessment.
Health and safety is a key consideration in experimental work and forms part of a good method. If you are working with animals or tissue, it is reasonable to expect there to be evidence that the guidelines for the use of animals in IB World Schools have been read and adhered to. The use of human subjects in experiments is also covered by this policy. If you are working with chemicals, some explanation of safe handling and disposal would be expected. Full awareness is when all potential hazards have been identified, with a brief outline given as to how they will be addressed. It is only acceptable for there to be no evidence of a risk assessment if the investigation is evidently risk-free—such as in investigations where a database or simulation has been used to generate the data. If you are using human subjects you should state that they will be required to complete a consent form including them to declare they are fit to engage in the activity and that they understand the procedures and any risks.
Extra information
It is often a good idea to carry out Preliminary investigations
Play with the equipment, do mini tests. This will help you work out:
If your idea will work
If your equipment choice is the right one
Whether you are examining the right range of data
If the concentrations/volumes/masses you are using will produce measureable results
If you can collect enough data in the time given to you.
Specify the research (biological) question to be answered
This should be a simple statement that refers to both the independent and dependent variables. Examples would be:
Investigate how pH affects the reaction rate of the enzyme amylase
Investigate how surface area to volume ratio affects the rate of osmosis
Once this has been stated have a longer follow on sentence such as,
pH will be changed using buffers and the rate of enzyme activity will be determined using...
Background Information
Outline the theory you are investigating. It is important to refer to accepted theory. Textbooks, journals and reliable websites can all be used to help support the research question.
N.B. references must be properly cited
Put the question in the form of a hypothesis.
To write a good hypothesis your first step should be to sketch a graph (no numbers, just a rough drawing) of what you think is going to happen. You may include the graph if you feel it helps, but you must express what the graph shows in words. Give a scientific reason and refer back to your background information.
If you are carrying out statistical analysis such as the T test split up your hypothesis into null and alternate statements.
The null hypothesis is a statement that you want to test. In general, the null hypothesis is that things are the same as each other, that there is no significant difference.
Determine which variables are relevant to the question
You are encouraged to explicitly list them out. It will make it clear in your mind what you have to focus on when designing the method. List out the independent and dependent variable. Identify as many relevant control variables as you can. The easiest way to lose a complete on aspect 1 is by not having an exhaustive list of control variables.
Before writing the method consider the following questions:
Looking back to your hypothesis decide what data do you need to produce the desired graph?
How will you process the raw data?
What raw data do you need to collect to support the processing?
You need to fulfill the 5 x 5 rule as a minimum – 5 different values of the independent variable and 5 repeats (so standard deviation can be calculated)
Beyond the 5 x 5 will your changes in the independent variable show a sufficient range and close enough increments to clearly produce the graph you desire? If not extend your range of measurements.
If you are taking samples (e.g. to estimate a population) is your sample size large enough to be reliable?
Method
A scientific method is most simply explained as a way of addressing all the variables you have identified: controlling the controls, measuring the dependent and changing (in a controlled way) the independent variable. In terms of the IA criteria this is aspect 2.
Though it is not required you are strongly encouraged to start your method by listing out the apparatus used. Don’t forget quantify the equipment where you can, e.g. measuring cylinder 10cm3 (± 0.05cm3).
Bullet point or number each step. Keep each step short, concise and clear.
Your method should address the following points:
How exactly does your method change the independent variable and what values are you choosing.
In detail say how you are measuring the dependent variable.
Give an example results table to show how you will record your findings.
Are you making up solutions/diluting solutions? If so detail this process, better show calculations and uncertainties in a table.
Assume all lab supplies given to you are prepared 100% accurately – your work is being assessed, not the lab technicians.
Address all control variables. Either by saying how you will keep them constant (the best option) or by randomising your samples so that variation should be roughly equal in all: e.g. I cannot accurately determine how moisture varies throughout the field so I will randomly place the 10 plots where I will use herbicide and 10 plots where I will not use herbicide.
Developing a method for collection of data
This aspect should already be accounted for as long as you have collected enough data:
5 x 5 rule is a minimum requirement when looking at how x affects y
For labs that will be analysed by t-tests 10 observations per independent variable change is a minimum
The method you suggest should be rigorous enough to collect the right data to allow you to investigate the research question. Get the first two aspects right and this last one should take care of itself.
Safety/ ethical/ environmental considerations
Unless you include any relevant information here you will not achieve beyond a 1. Make sure you have referred to the animal experimental policy if you are using animals (this includes humans).