Writing Materials & Method Section
Easiest. That's what has been said about the materials and methods section in thesis.
Is it really that easy?
Yes....
Only if you do it right.
You may think that you don't have to think a lot when you write this section.
You may think that it is just a matter of compiling all materials that you used in your research.
You may think you just have to write all the methods that you used in your research.
Sounds simple right?
Not really.
Let's have a look at the nitty-gritty of materials and methods.
So in this blog post, I will cover these commonly asked questions on materials and methods:
What is the materials and method section?
What is the purpose of materials and methods?
Why is the material and method section important?
What tense is used in the materials and method section?
What is the difference between materials and methodology in the thesis and methodology in the manuscript?
How do you write a MATERIALS section for a dissertation/thesis?
How do you write a good METHOD section for a dissertation/thesis?
What is the materials and method section?
The materials are simply the raw materials, tools, subject and/or important chemicals used in your experiments. Basically, it is the important details of WHAT you use in your research.
The methods section is HOW you conduct the research. Here, you describe all the steps or procedures you've done in order to achieve the research objectives, including the experimental design and data analysis.
What is the purpose of materials and methods?
To provide a precise description of (1) WHAT are used in the experiments, and (2) WHAT experiments are used and HOW the experiments are conducted to ensure you meet the research objectives.
Why is the material and method section important?
To ensure the credibility of your research. In other words, whatever materials/chemicals and procedures that you choose should be suitable and valid to answer your research questions.
To ensure the reproducibility of your methods so that other research may repeat your research.
To guide your readers on how the research is conducted and organized to tell a compelling story of your research. You may wonder what guidance has to do with your writing. I'll share with you more after this.
What tense is used in materials and method section?
Simple past tense because you're telling readers what you have done in the past. Normally, passive voice is used to focus on the action, not on the doer.
What is the difference between materials and methodology in the thesis and in the manuscript?
The methodology in the thesis is very detailed and thorough.
Depending on the thesis format of your university, you may add pictures or illustrations in flow charts to further describe or simplify your methods.
Or else, these illustrations can be placed in your appendices if your readers need further reference.
Methodology in a manuscript is simpler but with an emphasis on the reference so that the readers can refer to the original source.
It can be so simple like, "Method A was carried out based on the method by Clark, Teo and Li (2007)". This is practiced because a manuscript often has word limits.
However, if your sample preparations or method has not been cited anywhere and is newly developed, then by all means, please write it in detail.
How do you write a MATERIALS section for a dissertation/thesis?
In this part, you provide the details of your samples. Depending on your samples, the details should be thorough enough to describe your samples. If it’s animals or plants, provide the scientific name too. You can refer to previous thesis or publications closely related to your research for a better understanding. The examples are as below:
Provide where samples are purchased/obtained/harvested
Animals – age, after weaning, maturity
Plants – Maturity stage
Processed food – Provide brand, place of manufacture
You also capture the important chemicals used in your research. This information will provide accurate referrals for other researchers to repeat the experiments. Examples of information needed for chemicals:
Brand
Place of manufacture
Food or chemical grade
Molarity of chemicals
Concentration and activity of enzymes
How do you write a good METHOD section for a dissertation/thesis?
1) Organization
The method needs to be organized in a way that best tells your research story in the results and discussion. That means, your results and discussion should be in sync with the order of your written methodology.
Example of an organized method:
Materials
Preparation of sample
Experimental Design
Chemical properties
Method 1
Method 2
Method 3
Physical properties
Method 1
Method 2
Method 3
Thermal properties
Morphological property
Statistical Analysis
This simple example shows that the material section was written first, followed by the sample preparation and experimental design. Then, the experiments were properly categorized in chemical, physical and thermal properties; and lastly morphological property.
In this case, I prefer to organize the chemical section first because, in my discussion, I find it easier to relate the chemical properties with the physical and thermal properties.
Also, the physical properties are best placed before morphological properties because normally, the physical properties (and chemical properties for that matter) can be the explanation of why the morphology of the sample behaves in a certain way.
If I organize the morphological property after sample preparation, I will have a hard time explaining and linking the other results later in my discussion. See how important this is?
The best way is to look at examples in related journals or thesis; write it and get your supervisor's feedback.
2) Get your experimental design right
How to design a good experimental design you ask? This should be solved in your proposal stage, but I do want to highlight this a bit because it is super important.
If you need to design experiments yourself, refer to the previous thesis or well-published manuscripts.
Then, get feedback from your supervisor to check if your study covers the needed scopes and is designed correctly.
Finally, consult the statisticians for confirmation and get additional advice on how to further improve your experimental design.
One of the common mistakes that I see from students is that the experimental design is written without mentioning the control. This is a big NO-NO. You need control as a baseline to compare your samples. Without control, your experiment design is doomed.
Another common mistake is to have inconsistent variables. For example:
Group A: Control sample
Group B: Sample irradiated at 8 kGy for 10 minutes
Group C: Sample irradiated at 20 kGy for 5 minutes
Group D: Sample irradiated at 1000 kGy for 1 minute
Unless you have a really good explanation of why the irradiation power and exposure time differed so much, this experimental design is sooooo wrong.
An improvised version of the experimental design would be:
Group A: Control sample
Group B: Sample irradiated at 8 kGy for 2 minutes
Group C: Sample irradiated at 8 kGy for 4 minutes
Group D: Sample irradiated at 8 kGy for 6 minutes
OR, if the design needs to be more thorough and requires a range of irradiation variable, the improvised version would be:
Group A: Control sample
Group B: Sample irradiated at 8 kGy for 2 minutes
Group C: Sample irradiated at 8 kGy for 4 minutes
Group D: Sample irradiated at 8 kGy for 6 minutes
Group E: Sample irradiated at 16 kGy for 2 minutes
Group F: Sample irradiated at 16 kGy for 4 minutes
Group G: Sample irradiated at 16 kGy for 6 minutes
Group H: Sample irradiated at 24 kGy for 2 minutes
Group I: Sample irradiated at 24 kGy for 4 minutes
Group J: Sample irradiated at 24 kGy for 6 minutes
That's much better! I bet it can still be improvised.
The question now is; how do you write your experimental design in a good way? Should it be in a table? Should it be in paragraphs?
The answer is, it depends on your field. Also, try to write in the easiest form for the readers to understand. You can do multiple drafts of different versions to get a good feel of what’s best for your readers. Then, get feedback.
3) Determine your abbreviations for samples wisely
If your samples have long names, treatments or whatever categories, make sure to create abbreviations that are easy for your readers to identify in your thesis.
Some experimental design has multifactorial designs that are so complicated that it confuses readers, especially if you give a loooonnngggg gibberish abbreviation.
So, please, please, please...... help your readers to easily follow your story by giving simple abbreviations.
For example, let say you have 7 groups of rats (let's name it Sprague Dawley rats) treated with a new herb (let's name it QYZRS457, just for the sake of making it look complicated) to lower blood sugar level. So you might have your experimental design to be something like this:
Group 1: Control healthy Sprague Dawley rats untreated
Group 2: Control diabetic Sprague Dawley rats untreated
Group 3: Control diabetic Sprague Dawley rats treated with Metformin
Group 4: Healthy Sprague Dawley rats given herb QYZRS457 at 2%
Group 5: Healthy Sprague Dawley rats given herb QYZRS457 at 4%
Group 6: Diabetic Sprague Dawley rats given herb QYZRS457 at 2%
Group 7: Diabetic Sprague Dawley rats given herb QYZRS457 at 4%
Bad abbreviation for the 7 groups may look something like this:
Group 1: “CHSDRU” (As in Control Healthy Sprague Dawley Rats Untreated)
Group 2: “CDSDRU “(As in Control Diabetic Sprague Dawley Rats Untreated)
Group 3: “CDSDRM” (As in Control Diabetic Sprague Dawley Rats given Metformin)
Group 4: “HSDRQYZRS457-2%” (As in Healthy Sprague Dawley rats given QYZRS457 at 2%)
Group 5: “HSDRQYZRS457-4%” (As in Healthy Sprague Dawley rats given QYZRS457 at 4%)
Group 6: “DSDRQYZRS457-2%” (As in Diabetic Sprague Dawley rats given QYZRS457 at 2%)
Group 7: “DSDRQYZRS457-4%” (As in Diabetic Sprague Dawley rats given QYZRS457 at 4%)
Notice how confusing the abbreviations are! These abbreviations are created based on the first letter of bolded words. To make it worst, groups 4, 5, 6 and 7 have the abbreviations with the full code of the new herb!
You may think that I made up a ridiculous example. But believe me when I tell you it exists. I've seen it and I'm also the living proof that made this mistake before.
Now, let's try to make it simpler and better.
Group 1: “CH” (As in Control Healthy Sprague Dawley Rats Untreated)
Group 2: “CD” (As in Control Diabetic Sprague Dawley Rats Untreated)
Group 3: “CDM” (As in Control Diabetic Sprague Dawley Rats given Metformin)
Group 4: “H2” (As in Healthy Sprague Dawley rats given QYZRS457 at 2%)
Group 5: “H4” (As in Healthy Sprague Dawley rats given QYZRS457 at 4%)
Group 6: “D2” (As in Diabetic Sprague Dawley rats given QYZRS457 at 2%)
Group 7: “D4” (As in Diabetic Sprague Dawley rats given QYZRS457 at 4%)
Now the abbreviations are created based on the first words of the relevant keywords. I omitted "Sprague Dawley rats" because all of the subjects are known to be rats. I also omitted "untreated" because based on common sense, control will be untreated.
But I included the first word of "Metformin" in group 3 to differentiate the treated control group with a common drug. Then, I omitted "QYZRS457" because it will definitely be mentioned in the details of materials as the plant used. After all, the plant is the main cast of my research story. Finally, I included the concentrations in the abbreviation to differ the groups 4, 5, 6 and 7.
See if you can make a better abbreviation than this. I bet there are better options.
If your samples have short or simple common names, I suggest avoiding using abbreviations altogether and just stick to the word. It definitely will be less hassle for the readers.
4) Give the details in your method modifications
This is a common flaw made in thesis and manuscripts.
Often, modified methods will be written like this, "Method Z was carried out according to Yi et al. (2009) with a slight modification."
Is it wrong? No, but it is not accurate enough.
The best way to write it is to state what step/procedure/equipment/setting modified so that people know the changes. You might want to justify the reason why it is being modified too.
For example, "Method Z was carried out according to Yi et al. (2009) with a slight modification to the radiation power where 20 kGy was used instead of 25 kGy. The modification was done because the starch colour remained unchanged at 20 kGy as opposed to radiation power of 25kGy, where starch colour drastically changed to dark yellow."
Now the modifications are clear.
This is very crucial, especially if other researchers want to use the same method you've conducted.
5) Provide the details of your method
Write ALL the details of your method before the experiment is conducted. Then, double-check during and after the experiment. Finally, put it in a written form.
Examples are as below:
duration of study
time
temperature
force
oscillation
energy
beam
replicates used
size of population/samples
ethics
6) Highlight critical steps or precaution
My PhD work includes developing a method. After 2 years of multiple experiments, nothing worked. I almost gave up.
So, my supervisor asked his post-doc to help me out.
She did everything exactly the same as I did, except for one small step.
One of the steps requires the cooling of samples from 100°C to 50°C. I kept doing shock cooling by placing the hot samples into room temperature tap water in a beaker, then I placed the cooled sample into a 50°C water bath. Turns out, the shock cooling was the reason why I did not get the expected result.
The post-doc discovered that the cooling step to cool the sample from 100°C to 50°C by placing the hot sample into a 50°C water bath was the best procedure to get the expected result.
So, please learn from my mistake. I totally understand how important to highlight the crucial steps or precautions because even the tiniest, unexpected step may change the results.
7) Provide the references
This one may sound preeeettty obvious.
BUT, this is among the many mistakes my students made. If you don't write the references, it's as close as claiming the method as yours. Basically, it's plagiarism.
So, unless you develop your own method, please please make notes of your references for all the methods that you referred to and write it according to the format of your thesis.
I know that the referencing tool is pretty handy nowadays but always double-check to see if the format is right and the references in the text tallies with your list of references.
8) Provide the model, brand, manufacturer and the place manufactured for your main equipment/instrument used
As the title indicates, the main equipment or instruments should have all those details. I suggest that you have a table that compiles all the information so you can easily refer to it later.
9) Mind your units
As simple as it may seem, missing units or the wrong unit is what I always emphasize on my students.
In food processing research, students tend to use cups instead of grams or mL. And this might be the case for other fields too.
So always check whether your units are the valid ones. Always use SI units, unless there’s a special unit for the parameter.
10) Details of statistical analysis
Provide the statistical analysis software and the version used. Also, specify the type of analysis (ex: t-test, 2-way ANOVA, etc.) and the setting (ex: p-value). Your number of samples generally taken for each analysis (unless mentioned otherwise for some methods) is good to specify.
Conclusion
Looks easy right?
Maybe.
If. Done. Right.
Just as a recap, these are the things that you should be alert of when you’re writing the materials and methods section in scientific writing:
Provide the details of your materials and chemicals
Organize your methodology that bests tell your discussion.
Get your experimental design right
Determine your abbreviations for samples wisely
Give the details in your method modifications
Provide the details of your method
Highlight critical steps or precaution
Highlight critical steps or precaution
Provide the model, brand, manufacturer and the place manufactured for your main equipment/instrument used
Mind your units
Details of statistical analysis
Let the readers know you care for them.
So, always write with your readers in mind!
Do you have other tips on how to write a good materials and methods section? Or any burning questions to ask? Feel free to share or ask in the comment section.