Writing in the Sciences - Structure

This post covers how to improve sentence structures, and builds to to writing strong paragraphs. Most contents comes from the Writing in the Sciences course offered on Coursera.


Here is the list of punctuations ranked based on their power to separate:

The formality of these punctuations are ranked as:

A dash is a mark of separation stronger than a comma, less formal than a colon, and more relaxed than parentheses.

– Strunk and White


It connects two independent clauses (a clause always contains a subject and predicate; an independent clause can stand alone as complete sentence.)

Here is an example: ‘‘It was the best of times; it was the worst of times.’’

Semicolons can also be used to separate items in lists that contain internal punctuation. If some clauses contain commas, the comma inside the clause is no longer sufficient to separate different items in a list, because we don’t know where the boundaries are.


Parentheses are used to insert an afterthought or explanation into a passage that is grammatically complete without it.


Colons are used after an independent clause to introduce a list, quote, explanation, conclusion, or amplification.

The colon has more effect than the comma, less power to separate than the semicolon, and more formality than the dash.

– Strunk and White


Dash can add emphasis or insert an abrupt definition of description almost anywhere in the sentence.

Use a dash only when a more common mark of punctuation seems inadequate.

– Strunk and White

Here is an example illustrating how dash emphasizes and adds information: ‘‘Researchers who study shipworms say these mislabeled animals–they are clams, not worms–are actually a scientific treasure’’.

I like the example provided in the class to illustrate how to use dash to join and condense a sentence. The original sentence is:

Finally, the lessons of clinical epidemiology are not meant to be limited to academic physician-epidemiologists, who sometimes have more interest in analyzing data than caring for patents. Clinical epidemiology holds the promise of providing clinicians with the tools necessary to improve the outcomes of their patients.

By using dash, we can connect these two sentences together, whiling maintaining the description on physician-epidemiologists:

Finally, clinical epidemiology is not limited to academic physician-epidemiologists–who are sometimes more interested in analyzing data than caring for patients–but provides clinicians with tools to improve their patients’ outcomes.


It is often better–in scientific writing–to write paris of ideas joined by ‘‘and’’, ‘‘or’’, or ‘‘but’’ in parallel form.

Here is an example sentence with a list of things in parallel form: ‘‘NASA’s intrepid Mars rover, Curiosity, has been through a lot in the past year. It flew 354 million miles, blasted through the Mars atmosphere, deployed a supersonic parachute, unfurled a giant sky crane, and touched down gently on the surface of Mars’’.


There are several tips fo writing paragraphs:


It’s ok to repeat a word. It’s important to ask yourself if the second instance of the word necessary. If the word is needed, is a synonym really better than repeating the word? Using synonyms–especially in scientific writing–may lead readers to think you are referring to a different instrument, model, etc.

Other notes including Cut the Clutter, Verbs, and Writing Process are also available.