Writing physics and astronomy articles

Kansas University (KU) Writing Center published an 2-page instructor guide for those who are writing Physics and Astronomy articles.  The headings of the guide are as follows:

• Valued qualities
• Parts of an article
• Title block
• Body
• Figures and tables
• References in the text and as end notes
• General Style
• Sources

The sources used by the guide are very useful:

• Marquette University, Writing in Physics Courses.
• J. McLean, Physics Writing Guide, Dept. of Physics & Astronomy, SUNY Geneseo.
• A. Waldron et al., APS Physical Review Style and Notation Guide.

Guidelines for Laboratory Reports

by Quirino Sugon Jr.
Department of Physics
Ateneo de Manila University

(Date updated: June 13, 2012) The template for the undergraduate laboratory report in physics is Template for Transactions. Additional guidelines are given in the AIP Style Manual. The report should be between three to four pages. Only a hard copy of the report is submitted. It does not have to be colored.

Here are some of my additional guidelines:

TITLE

Title should be about 13 words.

NAMES AND AFFILIATIONS

For your affiliations, use your individual departments, e.g. "Department of Economics, Ateneo de Manila University, Loyola Heights, Quezon City 1108, Philippines"

ABSTRACT

Limit abstract to about four to five sentences. The abstract is the summary of your paper. State your problem, your means for solving it (methodology), your important results (results and discussion), and your conclusions.

I. INTRODUCTION

Limit the Introduction to three paragraphs. In the first paragraphs, describe the key concepts in your title. In the second paragraph, describe the applications of these concepts in your respective program of study. And in the third paragraph, state your problem and how you intend to solve it. Do not exceed two sentences.

II. THEORETICAL FRAMEWORK

First, start with the laws of physics and apply them to the particular problem of the experiment. You must draw figures, but the labels are theoretical parameters, such as mass $m$, height $h$, force $\mathbf F$, and angle $\theta$. Your main task in this section is to derive the working equation that relates the two or three concepts you mentioned in the title.

Below are some sample write-ups:


In one dimension, Newton's 2nd Law of Motion states that the force $F$ acting on an object of mass $m$ is proportional to the object's acceleration $a$: \begin{equation} F=ma. \end{equation} For a spring-mass system with one end of the spring attached to the roof and the other end attached to the object of mass $m$, the force on the spring is proportional to the change in length $\delta y$ of the spring: \begin{equation} \label{eq:F is k delta y} F = k\Delta y, \end{equation} where $k$ is the force constant of the spring. Also, under the constant gravitational acceleration $a=g$, the weight of the mass is \begin{equation} \label{eq:F is mg} F = mg. \end{equation} Equating Eqs.~(\ref{eq:F is k delta y}) and (\ref{eq:F is mg}), and solving for the spring constant $k$, we get \begin{equation} \label{eq:k} k = \frac{mg}{\Delta y}. \end{equation} Equation~(\ref{eq:k}) relates the force constant $k$ of the spring to the mass $m$ of the object, the constant gravitational acceleration $g$, and the change in length $\delta y$ of the spring.


Notice that the left side of Eq.~(\ref{eq:k}) is a parameter that cannot be measured directly, while those on the right is either a physical constant or a quantity that can be measured directly. The last equation of the theoretical framework should be the working relation that you wish to verify in the experiment.

IV. METHODOLOGY

A. Materials

Describe your equipment and its precision. If the equipment is special, describe its model number.

B. Methods

Describe your procedure for measuring the measurable variables in your working equation in Eq.~(\ref{eq:k}). You must draw figures. But unlike in Section II Theoretical Framework, the figures are now real world representations of the physical variables. Thus, instead of mass $m$, you have a block of wood. Do not anymore draw the force vectors, but only the string connecting the block to the spring. The spring, string, and block of wood should be labeled.

C. Statistical Toos

If you have some special statistical techniques aside from percent error and average, describe these here.

V. RESULTS AND DISCUSSIONS

Describe first the result, such as a figure or table, then comment on it. Answer the question: Does my result for the unknown parameter in terms of the known parameter results to a relation that agrees with my statement of the problem in Section I? Devote at least one paragraph for each figure or table.

VI. CONCLUSIONS

This section contains three paragraphs. In the first paragraph, summarize your problem, what you did, and your important results. In the second paragraph, discuss whether your results agree with your hypothesis in the statement of the problem in Section I. Explain why do you think it agreed or not. And in the third paragraph, write your recommendations to improve the experiment.

REFERENCES

You should have at least 3 references that is not from Wikipedia. These references should be cited in the Introduction or in the body of the paper.

Physics of Writing: Theory of Words and Paragraphs

I read in Physics Today last November 2011 that physicists have discovered the physics of writing:

The team, led by Ho-Young Kim of Seoul National University, considered two scenarios: the blot and the line. With the pen stationary, the researchers identify four main factors that affect the flow of ink: the capillary pull of the pen; the capillary pull of the pores in the paper; the surface tension of the ink; and the viscosity of the ink. When it is moving, the speed of the pen is a fifth factor.

 But I do not interpret the phrase "physics of writing" in the same way.

For me, the physics of writing is the science behind the art of writing: what is the best way to combine words to form phrases, sentences, and paragraphs given the background of both the author and the audience?  There may be some rules akin to Fermat's Principle of Least Time.  This principle, which states that light takes the path between two points $A$ and $B$ in such a way that time is shortest, can be used to prove the laws of reflection and refraction.  In the case of writing, we may also invoke Strunk and White's Principle of Least Words: "Omit needless words."  The dictum itself serves as its own example.

I think the physics of writing has already been with us starting from our grammar rules.  Unless you are a poet and you know what you are doing, you may break these rules from time to time.  There are also rules for style.  Copy-editors can spot style problems and fix them on the spot.  For example, you don't put an apostrophe here, a comma there, and oh--that should be a dash and not a colon. That's a wrong spelling, that is not Helvetica size 12, and references should include page numbers.  And so on.  But beyond grammar and style rules, there is the form of the writing itself.

In Platonic philosophy, forms are abstractions of material things.  In Physics, we refer to a formalism as something which translates physical reality into equations which can be manipulated to derive new results and predict new possibilities or realities.  The Maxwell's equations are examples of forms.  Dynamos, transformers, transistors, LED screens, radio communication, GPS navigation, electromagnetic pulse bombs, electromagnetic railgun are new realities or technologies derived from Maxwell's equations.

The forms of sentences and paragraphs became critical factors in the rise of Search Engines, such as that of Google.  Search engines try to guess the relevance of a particular article basing only from the keywords typed in the search bar. Search engines can measure keyword density (word phrase occurrence divided by total words or phrase in the article), inter-keyword distance, and other word analysis metrics.

I am interested in word content metrics, but not for search engine optimization.  Rather, I am interested in word content metrics to help physicists write better, such as the paragraph lengths and frequency of personal pronouns  in the Flesh Reading Ease Score and the Rudolf-Kincaid Grade Level.  I am also interested on sentence diagrams and I wish to extend these to paragraph diagrams, using something similar to Feynman diagrams.  I really believe that there is a physics to good writing; otherwise, it can't be taught.  Writing is an art. And all art is founded on science.

Michelson-Morley's 1887 paper: structural analysis via word spectra of earth and ether

Title should reflect content. This rule is obvious. But how the words are arranged in the title determines the structure of the paper. Let us look at the famous paper by Albert Abraham Michelson and Edward Morley in 1887: \begin{equation} \label{eq:michelson-morley} Title:\ On\ the\ relative\ motion\ of\ the\ Earth\ and\ the\ luminiferous\ ether. \end{equation} We treated this title as an equation, because we shall show that it can be expressed as an equation. In order to rewrite Eq.~(\ref{eq:michelson-morley}) as an equation, we do the following steps:

• Replace ":" by "=", "of" by "$\times$" or juxtaposition multiplication, and "and" by "$+$".
• Set $T = title$, $r = relative$, $m = motion$, $\epsilon = earth$, $L = luminiferous$, and $\xi = ether$.
• Make the adjectives as subscripts of nouns.  "Motion" is a noun while "relative" is its adjective, so we write $m_r$.  "Ether" is a noun and "lumineferous" is an adjective, so we write $\xi_L$.  

Using these three rules, we can now express Eq.~(\ref{eq:michelson-morley}) as \begin{equation} \label{eq:T is mr epsilon xiL} T = m_r (\epsilon + \xi_L). \end{equation}

We see in Eq.~(\ref{eq:T is mr epsilon xiL}) that $\epsilon$ (earth) and $\xi$ ether have equal footing as terms inside the parenthesis. So we expect the paper to talk about the earth and the ether at the same time in the discussion of their relative motion.  Michelson and Morley can adopt either of the two writing methods or both:

• Method 1:  Series Structure.  Paragraph 1 talks about the earth, Paragraph 2 talks about the ether, and Paragraph 3 talks about their relative motion.
• Method 2: Parallel Structure.  There is only one paragraph and most of the sentences mentions both the earth and the ether and their relative motion

The series and parallel structures are analogies borrowed from electric circuit theory.

Fig. 1.  Occurrence of "Earth" and "Ether" in the Michelson-Morley paper.  The paper starts from the right (top of the paper) marked by the scroll bar arrow and the paper is read to the left (bottom of the paper)

One way of analyzing the structure of Michelson-Morley's paper is analyze the occurrence of the words "Earth" and "Ether" in their manuscript.  To do this, we go to the web page containing Michelson-Morley's paper, click CTRL+F and type "Earth" in the search box.  The occurrence of the word "earth" will be highlighted in yellow along the scroll bar.  Repeat the process for the word "Ether".  What you get is similar to the atomic spectra of two different elements.  We shall call this the word spectra.  Notice that the word spectra of "Earth" is very similar to the word spectra of "Ether".  If we define a word occurrence distribution function $f(x)\delta x$ for the two spectra, such that the smallest interval size $\delta x$ contains several spectral lines for each word, then we see that the overlap integral of the two distributions functions would be positive, which is a mark of parallel writing structure.  If the overlap integral is zero, then the writing has a series structure.

Another way of analyzing the paper's structure is to construct a circuit diagram of the paper, with "Earth" and "Ether" as circuit elements.  I will talk about this in another post.

Methodology and Results: Action-reaction and heat engine models

Linda Yezak of Author Culture applied to writing Newton's Third Law of Motion: for every action, there is an equal and opposite reaction. Mathematically, we say that if mass $A$ exerts a force $\mathbf F_{AB}$ on mass $B$, then mass $B$ exerts a force $\mathbf F_{BA}$ on mass $A$, such that \begin{equation} \mathbf F_{AB} = -\mathbf F_{BA}. \end{equation} Since this is a vector equation, then the magnitudes of these two vectors are equal, $F_{AB}=F_{BA}$, and their directions are opposite, as expressed by the minus sign. What Yezak is saying that if character $A$ acts on character $B$, character $B$ must show his reaction. If we name $A$ as Anna and $B$ as Bob, then it is not enough to say that Anna spanked Bob. Bob must show a reaction. He may ask, "Why do you strike me?", in the same way as Christ asked the soldier of Annas the High Priest (c.f. Jn 18:23).

In physics writing, $A$ can be thought of as the Methodology and $B$ as the Results. If in the Methodology you say, "we measured the temperature of the water as a function of time," then in the Results you must provide a table showing the relationship between temperature $T$ and time $t$ or you must provide a figure showing temperature in the vertical axis and time in the horizontal axis. Whether you use a table or a figure, you must show units of measurement. The temperature may be in Celsius or Kelvin. The time may be in seconds, minutes, or hours. A number without units is not a physical quantity. 

One example of a graph of the rise of temperature vs time of water is shown in Chem Team. You will see that there are 5 major features: 

• Ice rises in temperature until the freezing point of $0^\circ$ C.  The graph is linear with positive slope
• Ice melts at $0^\circ$ C.  The graph is horizontal until the amount of heat absorbed is equal to the heat of fusion
• Liquid water rises in temperature to $100^\circ$ C.  The graph is linear with positive slope
• Liquid water changes to steam at $100^\circ$ C.  The graph is linear until the heat absorbed is equal to the heat of vaporization
• Steam rises in temperature.  The graph is linear with positive slope.

In story writing, when Anna hits Bob and Bob asks, "Why do you hit me?", The story does not end there.  Like a boulder rolling from the hilltop, the story should move forward and gain momentum like a heat engine: Anna, Bob, Anna, Bob, Anna, Bob,.....  We can see this, for example, in Shakespeare's Julius Caesar, Act 3, Scene 1:

• Brutus kills Caesar.
• Caesar says, "Et tu, Brute?  Then fall Caesar!"
• Caesar dies.  Brutus and company bathe their swords in Caesar's blood.
• Brutus speaks about Caesar.

Notice the engine cycle: Brutus, Caesar, Brutus, Caesar, Brutus, Caesar,....

Similarly in writing the Results, there should always be a discussion that relates it to the Methodology.  That is why the section is rarely called Results but Results and Discussion.  You get this graph, because you used this water.  You varied the heat input by increasing the fire, and the result is a shorter time interval at the phase changes.  You lessened the mass of ice, but also lowered the heat input; the the time interval for the phase changes remain the same.  Method, result, method, result, method, result,....  This is the heat engine that drives your Results and Discussion.

Installing MathJax in Blogger for LaTeX Equations

Physicists write equations a lot and the best typesetting program for equations is not MS Word but TeX or LaTeX. The problem is that you have a LaTeX document and you want this reflected in your blog posts and pages. Unfortunately, web pages are written in HTML and not in LaTeX. So what will you do?

One solution is to blog using Wordpress and enclose your Latex equations with $\$latex\ \ldots\ \$ $, where the $\dots$ are where you write your equation (see Wordpress LaTeX support). The only problem is when you wish to align your equations using the align environment. This is not supported by Wordpress.

I tried to get around this problem by writing my manuscript in LaTeX. Then I screen-grab the pdf images, upload the images in my Google+ page, and post these images in my Wordpress page. You may like to check out the finished product in Ateneo Physics Teacher: Projectile motion of a waterfall. Since the Google spider can't see pictures, I use Wordpress tags using keywords from the article, hoping that the spider will somehow see the page and rank it in the first page of certain search queries. Had the article been text and images, the web page ranking would have been higher.

 Another solution is to blog using Blogger. Unlike the free version of Wordpress hosted in wordpress.com, Blogger allows the use of scripts. In this blog, I use MathJax scripts.

To see how easy it is to use MathJax, go to MathJax download page.  Click on Using the MathJax CDN.  CDN means Content Distribution Network. Copy the sample HTML file with script. The file is on how to typeset the quadratic equation in-line and the quadratic formula in display.

Equations may also be written using LaTeX's equation and align environments. Equation labels and references are supported. You may use the equation numbering feature in MathJax. But you need to insert a script just before the script tag that loads Mathjax itself. Unfortunately, subequations are not supported.

As an illustration of MathJax's capability, the unified Maxwell's equation in geometric algebra is written as \begin{equation} \label{eq:Maxwell} \left(\frac{1}{c}\frac{\partial}{\partial t}+\boldsymbol\nabla\right)(\mathbf E +i\zeta\mathbf H) = \zeta(\rho c - \mathbf j), \end{equation} where $\zeta=\mu/\epsilon$ and $c=\sqrt{\mu\epsilon}$. Using the Pauli identity $\mathbf a\mathbf b = \mathbf a\cdot\mathbf b + i(\mathbf a\times\mathbf b)$, the Maxwell's equation in Eq.~(\ref{eq:Maxwell}) expands to \begin{align} \boldsymbol\nabla\cdot\mathbf E &=\frac{\rho}{\epsilon},\\ \frac{1}{c}\frac{\partial\mathbf E}{\partial t} -\mu\boldsymbol\nabla\mathbf H&=-\zeta\mathbf j,\\ \boldsymbol\nabla\times\mathbf E +\mu\frac{\partial\mathbf H}{\partial t} &= 0,\\ \zeta\boldsymbol\nabla\cdot\mathbf H &= 0, \end{align} after separating the scalar, vector, imaginary vector, and imaginary scalar parts. Note that we have factored out the imaginary number $i$ in the last two equations. These four equations correspond to the Gauss's law, Ampere's Law, Faraday's law, and Magnetic Flux Continuity Law, respectively.

Why I am writing the Physics Writers Guide

After 15 years of writing research papers and 10 years of teaching and supervising physics thesis students in Ateneo de Manila University, I realized that physics students need help in writing paragraphs, whether it be for a thesis, a conference paper, a journal article, or a book chapter. Not because the students are bad in writing, but simply because they are not taught.

The students in our university take 12-15 units of English classes:

• En 11 Communication in English 1. This is where I learned how to write paragraphs, especially the importance of parallel structure in writing. I forgot to mention that there is still an En 1 Basic English course for those who failed the paragraph writing exam in the first day of the English class. I was one of those lucky few who learned Basic English.
• En 12 Communication in English 2. This is a where I learned to make a research paper by reading lots of books. Research was difficult then. I searched the card catalog in subject and title cards. I searched the microfilmed newspapers by staring at projector monitor. I collected index cards and wrote entries by hand. I typed my thesis in a gravity-powered typewriter with a broken spring for the carriage return.
• Literature 13 Introduction to Fiction. I was able read many short stories, such as the "Cask of Amontillado" by Edgar Allan Poe and "The Necklace" by Guy de Maupassant. In Lit 13 I learned textual deconstruction.  Now, I learned how to textually deconstruct the deconstruction.
• Lit 14 Introduction to Poetry.  This is my favorite course.  I never knew that I would love poetry.  I love many poems, such as "Daffodils", "Fifteen Million Plastic Bags," and "Tiger."  I have a preferential option for lyrical poetry, the poems that I can sing.  My favorite lyrical poet is J. R. R. Tolkien.  I can sing most--if not all--of the poems in the Lord of the Rings. I love to sing the "Oliphaunt," "The Battle of Felagund and Sauron," "O Lorien", "O Boromir," "The World Was Young," "O Elbereth", and "When Evening in Shire Was Grey."  
• En 26 Introduction to the Essay.  I can't find any link to this course anymore.  I guess the university dropped it from the Revised Core Curriculum.  But this course provides a good overview of different forms of essays used in different media: newspapers, magazines, books.  The web was still in its infancy during my time and I never used it in my college days.  I only learned to appreciate essay writing years after I took the course.  My favorite writers who write about writing are Strunk and White, Rudolf Flesch, and Roy Peter Clark.  My favorite essayist are G. K. Chesterton and Hilaire Belloc.  Albert Einstein is also the master of the prose.  His one-liners are literary nuclear bombs: "Imagination is more powerful than knowledge" or "Make things as simple as possible, but not simpler".

But there is no course on writing for mathematicians and physicists. This is understandable because the only person who can teach such course on "Writing for Physicists" should also be a physicist himself, and very few physicists would take interest in the art of writing--or in the physics of writing, if such a thing ever existed.

Writing for physicists is not an ordinary writing job:  

• Equations.  There are monstrous equations in physics that really look and sound Greek to non-physicists, e.g., Einstein's Field Equations.  I haven't yet added Hebrew into the mix and all those math symbols such as divergence, curl , and triple integrals, e.g. Maxwell's equations in differential and integral forms.  Though LaTeX has made equation typesetting straightforward, you still have to introduce and explain equations in plain English.
• Structure.  Most papers in physics have predefined structures: Title, Authors, Abstract, Introduction, Theoretical Framework, Methodology, Results and Discussion, Conclusions, Acknowledgments, and References.  But knowing these alone does not result to a paper for publication, in the same way as a stick figure with a circle is not Michelangelo's David.  
• Marketing.  Physicists are in the business of selling their ideas to the physics community; their ideas are sold when another physicist accepts their ideas to be true.  Usually, the minimum requirement is to convince two people: the editor and the reviewer.  But this alone are not sufficient: the physicist author still has to convince other physicists after his work is published until the end of time, e.g. Galileo still has to convince Einstein.  Physicists do not see themselves as marketers, but part of their job is to advertise: the abstract is like a billboard and the Introduction like a full-page magazine ad.

So in this blog, I will be writing about the physics of writing in a language understandable to physicists.  Non-physicist readers may be put-off by some esoteric language, such as how the Schrodinger's cat is like the Cheshire cat: now you see it, now you don't.  But I am catering to a very narrow audience, and in doing so I hope to be helpful to many who wander in their thesis and are really lost.