SCIENTIFIC WRITING Based mainly on the AIP Style guide and

The Technical Writer’s Handbook by Matt Young.

OVERVIEWThe structure of scientific reports

Writing with clarity Scientific style conventions

Mandatory style conventions

Debated style conventions

The Structure of the Report Title

The title should be descriptive and informative. Abstract

The abstract should state very concisely (usually in one paragraph) the scope and nature of the subject discussed, the basic method or approach, and a summary of the major results. The abstract should stand alone without reference to the rest of the paper.

Introduction The introduction should outline for the reader exactly what is to be discussed in the paper, the purpose of the work, and a brief history of previous work relevant to the investigation. It gives us the big picture, so that we have enough context to understand the Theory and Procedure sections.

Theory Experiments are designed and performed within a theoretical context. Describe this context here and summarize, motivate, or derive the relevant equations. Equations should be treated like words in sentences.

Procedure Briefly describe what you did in full sentences and complete paragraphs. Don’t write this section as a numbered list of steps, and don’t imitate a lab manual. Use the past tense. Figures of the apparatus, including either schematics or digital photographs, are often valuable here. Focus on the essence of the experiment, not on the knobs that you turned.

Results and Analysis Concisely summarize your results and discuss them. This section will probably include plots and tables to display your results. Talk the reader through the results -- explain, explain, explain! Talk the reader through the important things to notice when looking at the figure. Plots and tables do not stand alone; each one must be discussed in the text. All graphs, figures, and tables must be labeled and captioned.

Conclusion or Summary Tell the reader again whatever you want them to remember. Draw what conclusions you can based on your data. Uncertainty should normally be discussed. In some cases you may have to say that no conclusions can yet be drawn from your data. Acknowledgments, References, Appendices

Before beginning to write

Analyze the problem:

Exactly what information do I wish to present in this paper?

For what specific group of readers am I writing?

What background information can I assume these readers have?

What is the most logical sequence in which I should present the information to the readers?

General rules for writingBE CLEAR

Consider the beauty and efficiency of the simple declarative sentence as a medium for communicating scientific information.

BE CONCISE Avoid idle words; Make every word count.

BE COMPLETE Do not assume your reader has all the background information you have about your subject matter. Make sure your argument is complete and logical. Avoid jargon.

BE SELF-CRITICAL Put yourself constantly in the place of your reader. Ask yourself “Is there any way in which this passage could be misunderstood by someone reading it for the first time?”

The value of clear writing

“I personally believe that most sloppy writing is just sloppy thinking made manifest, and that by focusing on writing better, scientists become better scientists, too. Writing disciplines your mind, and the act of reducing amorphous thoughts to structured, formal language crystallizes your thinking in a way that nothing else can.”

Celia Elliott, Science Writer, UIUC

WRITING WITH CLARITY

Minimize your reader’s effortKeep the action in the verb

We often turn verbs into nouns (called nominalization).

Compare:

We analyzed the data.

We performed an analysis on the data.

Keep subjects and verbs close together

Minimize your reader’s effortThink about how you are introducing new information

Sentences usually include a mix of old (ideas you’ve already introduced in the paper) and new. Writing is usually easier to understand if the sentence starts with the old rather than the new. It helps us see the connection to what we already know.

Keep paragraphs coherent

What is the main point of the paragraph?

Do the topics of the first & last sentences match?

Minimize your reader’s effortChoose words carefully

We measured the field with a gauss meter.

We measured the field with the gauss meter.

Be specific

Extra words and fancy words do not make you sound smarter.

“It should be noted that the aforementioned …”

YOUNG’S FIRST RULE

Write the way you talk; then polish.

DEAD WORDS

I have made this letter longer than usual, only because I have not had the time to make it shorter.

– Blaise Pascal

If I had more time, this letter would be shorter.– Voltaire

Orwell said, “If it is possible to cut a word out, always cut it out.” Today

we might cut the two instances of out from his sentence, but they are not

exactly instances of dead or meaningless words. Dead words are phrases

like it is seen that, it is well known that, it is found that, recall that, and

note that and its partner it should be noted that. These words have no

real meaning. When they are used to excess, they do not do the job they

are supposed to do: to highlight points you want to make strongly.

The best way to highlight some point is to do it with your writing or

your punctuation. For example, instead of writing it should be pointed

out that all the time, find the sentence you really want to stand out,

polish it, and give it a paragraph all its own.

Examples:

From The Dictionary of Concise Writing:

She said she was 'in the process of cleaning the house.' I thought, How is that different from simply 'cleaning the house'?''

an overwhelming majority of -> most to a certain extent -> in part is of the opinion that -> believes

This is a result of the fact that aluminum and copper plates of different thicknesses were used in this particular study with materials on hand.

This is because aluminum and copper plates of different thicknesses were used in this particular study with materials on hand.

FALSE ELEGANCE

False elegance is using long or pretentious words where common words

exist. For example, using utilization for use, in view of the fact that for

because, and therein for in it are examples of false elegance.

Much advantage accrues to this method from the availability of fluorescent dyes

is a falsely elegant way to say

Fluorescent dyes have proved valuable to us. ➩

Other writers achieve false elegance by elegant variation, or changing

words to avoid repeating a word within the same sentence or paragraph.

Indeed, bad writers often go to great lengths to avoid repetition. Why?

You don’t get variety, say, by switching to fabricate just because you

have just used build, or switching to employ because you have just used

use. Use the word that sounds most natural to you, and don’t worry

about getting variety by an artificial device.

We calculated the mean and standard deviation; the average was 17.0.

Average and mean are synonyms here but why change terminology in mid-sentence?

We calculated the mean and standard deviation; the mean was 17.0.

''Never use a long word when a diminutive one will do.''

-William Safire

VAGUE WORDS, VOGUE WORDS

Sometimes difficult to distinguish. A vague word is a word that does not

have a precise meaning or is not precise enough for a given application.

Typical vague words are nice, fine, really, good, bad, and, in many

contexts, important, kind, type, character, relative, appreciable, or

device. If you use an adjective, for example, but always have to

intensify it with a word like actually, very, totally, extremely, or

exceptionally, drop the intensifier or look for a more precise adjective

that means what you want to say. ➩

A word like apparatus or device can also be a vague word. For

example, do not write

We used a device that dispersed the light into its constituent colors.

We used a prism spectrometer to disperse the light into its constituent colors.

Words like imperative and essential (and their adverbs) are vogue

words, that is, words that are in style and have lost much of their

strength. For example, essential does not mean just important; it means

of the utmost importance. If you have to intensify it with extremely, you

are using a vogue word that has lost much of its force... ➩

In this context, device is too vague; tell us what kind of device:

Adjectives like appreciable, relative and reasonable are also vogue

words and may be vague. Relatively large in microscopy is not even

significant in astronomy. Therefore, don’t write

The surface feature was relatively large,

The surface feature was several kilometers across

but, rather, something like

or

The surface feature was easily resolved by the telescope.

SCIENTIFIC STYLE (MANDATORY CONVENTIONS!)

EQUATIONS

The lens equation is

where f ´ is the focal length.

1 / L ´ - 1 / L = 1 / f ´, (23)

Very short equations [with italicized variables] may be used in

sentences:

Longer equations are given lines of their own and usually numbered

along the right margin. These equations are also best treated as parts of

sentences and, in most publications, are also punctuated as such:

Points r < a are in the core of the fiber.

The line extends from x = a to x = b.

Define all your variables, but try to avoid giant lists of variables.

NUMBERS IN SENTENCES

There is an arbitrary rule that you spell numbers less than or equal to

ten; some people add to this round numbers such as twenty, thirty, and

one hundred. (Others spell unity and zero as well.)

In technical writing, the rule applies only to numbers used to indicate

quantity (not numbers that we are using for calculations). Thus, we

write two radio transmitters, but a factor of 3.

Many countries use a comma, not a dot, as the decimal marker. In

numbers with lots of digits, therefore, separate the digits into groups of

three and leave spaces, not commas, between groups. Count both ways

from the decimal point and write, for example,

299 792 458 or 5.640 51,

but not

299,792,458 or 5.640,51.

Leave out the space when only four digits are involved (1066 not 1 066),

unless the number appears in a table with longer numbers.

SI UNITS

Write the units in Roman type, not italic. (Variables are italicized.)

Thus, 6 m indicates a length of 6 meters,

while 6 m indicates a mass a factor of 6 larger than the mass m.

When you spell the name of an SI unit fully--hertz, decibel, mole, meter--do not capitalize it even if the unit is named after a person (except at the beginning of a sentence or where you would otherwise capitalize). When you abbreviate a unit--Hz, dB, mol, m--capitalize the abbreviation only when the unit is named after a person.

The International System calls for a space between the number and a unit or its abbreviation. That is, write 9.8 cm, not 9.8cm. ➩

Avoid abbreviating units when they are not associated with a number:To cool an atom from 300 K to mK temperatures requires 10 000 scattering events.

Rewrite to spell out the unit completely:To cool an atom from 300 K to millikelvin temperatures requires 10 000 scattering events.

NAKED DECIMAL POINT

A decimal point is a little thing; it can easily get lost. Do not leave your

decimal points naked but precede them with a digit. That is, when

reporting numbers less than 1 write them with a leading 0:

0.7071, not .7071

OTHER CONVENTIONS

Contractions: Don’t use ’em in technical writing.

Uncertainty:

Only 1 sig fig in the uncertainty

Uncertainty and value end at the same place

Same scientific notation exponent for both values

Wrong: 0.646 ± 0.151kg m2/sec

Right: 0.65 ± 0.15 kg m2/sec

References:

Note that borrowing a figure requires more explicit citation than borrowing general ideas. I discourage indiscriminate copying of images from the web.

SCIENTIFIC STYLE (DEBATABLE CONVENTIONS!)

Passive voice

First-person

Gender neutral language

(he, he or she, they)

EXAMPLES

Sample AbstractThe purpose of this experiment is to create and study chaos in a

mechanical system. The specific system studied herein is that of a forced damped harmonic oscillator with a bi-stable equilibrium. This system can act chaotically when conditions are set up in some ways, while it exhibits perfectly ordinary periodic oscillations when the conditions are set up in other ways. In this report, several different ways by examining different graphs of the data, including phase diagrams and Poincare plots, are used to show that the system exhibit chaotic motion. It is also informative to examine the Fourier transforms of the data to see the dependence of the chaotic system on the driving frequency. Fourier transforms of the data were also taken to show that the driving frequency has a significant effect on the chaotic oscillations of the system.

Sample ConclusionChaos was observed in the mechanical system for runs B and C.

This was seen in the erratic behavior of the angular position vs. time graph. The complete filling of the phase space on the phase diagram indicated chaos was present. The swirl shape of the Poincare plot was indicative of chaotic motion. Finally the divergence due to initial conditions observed between runs B and C constitutes fairly solid evidence that the parameters set for those runs do induce chaos. We also observed that while the driving frequency was very important to the low amplitude steady state of Run B, it was not the most important oscillation frequency during the high amplitude chaotic state of the same run. The Fourier transform of the whole of Run B shows that it has contributions from a large number of frequencies, although the driving frequency is the most prevalent, which further indicates that the system is experiencing erratic and chaotic behavior.

ADDITIONAL RESOURCES

Ms. ParticularResources from Celia Elliott, University of Illinois Physics Dept

Ms. Particular

“Writing well is not an art, it’s a craft. It requires learning basic

techniques, practicing them over and over, getting feedback, and

writing with the expectation that you'll rewrite, sometimes many

times. So keep practicing!”

Celia Elliott, Science Writer, UIUC