An abstract is a specific kind of a summary included with various kinds of scientific publications.
There are a lot of different ways to summarize a scientific article or other document. The title itself is sort of a one-line summary. An outline is also a summary. An “executive summary” is often a statement of the basic idea in simple terms. The National Science Foundation requires a summary of a grant proposal in non-technical language for an educated non-scientist.
An abstract has certain features that set it aside from these.
An abstract is an ordinary part of a research article in a journal; only a small percentage of journals do not require them. Abstracts are also usual for review articles. There are other places where abstracts are used, as well:
The more familiar you are with the contents of an article, the easier it is to write an abstract. If you wrote the article yourself, you obviously know what is in it, but professional abstract writers routinely make abstracts of articles they haven’t written, and you can, too. The first step is to identify the major point or points of the article. Sometimes it helps to make an outline, but that is not always necessary. When you have written down the main points, then look to see what information is crucial to lead up to those points. The research methods might be important if they are new or unusual, but if they are standard, they only need to be referred to briefly. Next, write down the conclusions that are drawn from the main points. When you are done, you will have something like this:
Yes, this is sort of a “mini-outline”. Next, you turn it into a paragraph. Scientists have grappled for years over the appropriate way to talk about discoveries: should it be “we measured ion concentration in the blood” or “ion concentration in the blood was measured”? The first example is in the active voice and the second example is in the passive voice; modern scientific style prefers the active voice. Abstracts are often an exception, but only if the passive voice reduces the total number of letters and words. With abstracts, the bottom line is brevity: They should be as short as possible and still include the important information.
The best source of example abstracts is journal articles. Go to the library and look at biology journals, or look at electronic journals on the web. Read the abstract; read the article. Pick the best ones, the examples where the abstract makes the article easier to read, and figure out how they do it. Not everyone writes good abstracts, even in refereed journals, but the more abstracts you read, the easier it is to spot the good ones.
Citation: Clark, Curtis. 2001. BIO 190 - Writing an abstract. California State Polytechnic University, Pomona, http://www.csupomona.edu/~jcclark/classes/bio190/abstract.html.