As an undergrad:
You’ll be expected to write Abstracts for physical lab reports, and for assessed written exercises. An Abstract is different from an Introduction or Aim, which you’ve written for lab reports already. An Abstract is a short paragraph covering the important points of the report – a reader can use this to determine whether the report or paper is relevant to them.
A Good Abstract Contains 4 Things
1 – What was the ‘aim’ of the experiment?
What were you trying to find out? The lab manual might tell you that the point is to give you experience of the technique. This is not the aim of the experiment – in general the aim is to calculate, measure, compare, determine, quantify, investigate or study a system, reaction or physical property.
2 – What experimental methods or techniques did you use?
Did you use chromatography? NMR? UV-Vis spectroscopy? State whatever equipment or technique you used to get your data.
3 – What was your result?
State the actual numerical result you got from your data, including any associated errors and units.
4 – What was the conclusion?
What did you conclude from this experiment? Was your result close to the literature value? Did you answer the question from your aim?
Here are two Abstracts, about the same experiment, written in two very different ways.
The aim of this experiment was to determine the dissociation constant of bromophenol blue (BPB). UV-visible absorption spectroscopy was used to measure the absorption peak of 6 stock solutions of varying pH. The values of optical density measured were then used to determine pKa values using the Henderson-Hasselbalch equation. The dissociation constant for bromophenol blue was found to be 1.2310 x 10^-4 M ± 3.2 x 10^-9 M.
Bromophenol blue is very useful as a dye and as an acid-base colour indicator similar to phenolphthalein. At neutral pH, the dye is very blue but at low pH, the dye appears yellow in solution. After becoming familiar with how to use the spectroscopy equipment, we prepared several solutions and recorded the absorption spectra at the same time. A solution of 0.025 M potassium hydrogen phthalate was used as the blank. The dissociation constant of bromophenol blue can be calculated by using the absorption peak at different pHs.
When you write an Abstract, imagine you’re a researcher trying to Google published papers on your topic. Your time is important – you may have experiments running that need attention – reading well written abstracts helps you with decision-making. A PhD student who’s also busy with marking undergraduate lab reports needs to make quick decisions on publications relevant to their own research.
As an added bonus, if you can write a short paragraph explaining the point of a paper, it’ll make understanding and organising material for literature reviews that much easier.
Keep it simple, keep it short, and make sure you include all the information you need to make your point.