Punctuation!

How to punctuate correctly and why it matters

Punctuation is important. First of all, it is important because some punctuation marks are indicators of syntax. For example, the full stop marks the end of a sentence, and the comma may mark the end of a clause. Secondly, even punctuation which is not essential helps the reader to quickly understand the phrasing of a sentence. These are marks which in speech would be indicated by pauses, intonation, stress and even body language like raised eyebrows or twitchy fingers.

Most punctuation marks have more than one function and we'll examine each one in turn. The first group contains the stops. They are the full stop, or period ( . ), the comma ( , ), the colon ( : ), the semicolon ( ; ), the ; ( ? ), the exclamation mark ( ! ) and the dash ( – ).

The second group contains all the other punctuation marks. They are the apostrophe ( ' ), the hyphen ( ‐ ), quotation marks ( " " ), parentheses ( ( ) ), brackets ( [ ] ), ellipsis ( . . . ), italics ( word ), and capitalization ( The first letter is capitalized. ).

The Full Stop or Period ( . )

The main function of the full stop is to end a sentence.

No one knows who invented music.
The only other ways to end a sentence are with question mark ( ? ), or an exclamation mark ( ! ).
The full stop is also used in some abbreviations: e.g., Mr., Jan. etc.

The Comma ( , )

One of the simplest uses of a comma is to separate items in a list.

Patterns like these begin to form at a small scale when materials undergo processes like drying, freezing, wrinkling, diffusing and reacting.

There are five items in this list. The last item is usually introduced by the word 'and', and the comma may be left out as in this case.
There are many more uses for the comma such as separating adjectives, separating an adverbial clause from a main clause, and separating coordinated independent clauses. You can see many examples of these on the comma page.

The Colon ( : )

The main use for a colon is to provide a specification in the form of a definition or specific example.

That’s all gravity is: the distortion of the space-time fabric, affecting how things move .

The colon is sometimes used to introduce a quotation. You can see more examples on the colon page.

The Semicolon ( ; )

The semicolon is mainly used to separate independent clauses.

Most foods contain at least some sugar; once foods are between 230 and 320 degrees, their sugars begin to turn brown.

The semicolon is also sometimes used to separate items in a list and to separate a subordinate clause from a main clause. You can see more examples on the semicolon page.

The Question Mark ( ? )

The question mark is used at the end of a direct question or at the end of a rhetorical question.

Imagine delicate frozen crystals on a windowpane during a cold day. What creates that pattern?

This is a rhetorical question. The writer is not expecting an answer. He is using the rhetorical question to set up the topic of the paragraph, which concerns how patterns in ice and rock are created. This is the main use of questions in academic text; direct questions are rare.
You can see more examples on the question mark page.

The Exclamation Mark ( ! )

The exclamation mark is used at the end of a sentence, or occasionally with a sentence, to give emphasis to a preceding word or phrase or to draw your attention to something extraordinary. It is not much used in academic writing.

When the scientists measured how much carbon-14 was left in the flutes – which were made from the bones of large birds – they discovered some of the instruments were more than 30,000 years old!

You can see more examples on the exclamation mark page.

The Dash ( – )

The dash is used around dependent clauses, around interrupting phrases, to introduce coordinated elements, and to mark final constructions. It is often used where a comma or parentheses might be used. For example to separate an appositive noun phrase.

All living organisms – animals, plants and people – have some carbon-14 in them.

A dash is not the same as a hyphen. It is used in a different way and it is longer than a hyphen. It may not be present on all keyboards, but you can create the dash by pressing the hyphen along with the ALT or OPTION key.
You can see more examples on the dash page.

The Apostrophe ( ' )

The apostrophe is used to show possession (Newton's laws) and contraction (That's enough).

While it warms us and all the plants and animals on Earth's surface, sunlight can't penetrate through miles of the planet's interior.

You can see more rules and examples on the apostrophe page.

The Hyphen ( - )

The hyphen is used in certain compound words (e-book, self-help, eye-witness, evidence-based).

The sound of the ocean is also a low-frequency sound.

You can see more examples on the hyphen page.

Quotation Marks ( " " )

Quotation marks are used for direct quotations, some titles, and to signal words which are used with a special meaning.

In the 1930s the Austrian psychotherapist Alfred Adler was the first to study birth order and its effect on personality. He believed that “every difficulty of development is caused by rivalry and lack of cooperation in the family ” .

You can see more examples on the quotation marks page.

Parentheses (brackets) ( ( ) )

Parentheses are used to enclose a word or phrase which gives extra information but which is not a strictly necessary part of the sentence.

These are animals or other organisms that live on (ectoparasites) or in (endoparasites) another species.

You can see more examples on the parentheses page.

Brackets (square brackets) ( [ ] )

Square brackets are used inside a quotation to enclose a word or phrase which is not part of the original quoted text, or to indicate that something is missing in the quoted text.

Staggeringly, in 1996 the company’s chief executive, Lee Raymond, referred to “ the unproven theory that [fossil fuels] affect the earth’s climatequoted text” .

You can see more examples on the brackets page.

Ellipsis ( . . . )

Ellipsis is used to indicate that there is something missing from a quotation.

Pinker writes: “The errors children . . . make are rarely random garbage. Often the errors follow the logic of grammar so beautifully that the puzzle is not why children make the errors, but why they sound like errors to adult ears at all” (The Language Instinct, p. 273)

Italics ( italics )

Italic formatting is used for titles in citations, for foreign words, for scientific names, and for emphasis.

The discourse on Jean-Jacques Rousseau's theory of language has, hitherto, focused mostly on his Discourse on Inequality (1755/1984) and the Essay on the Origin of Languages Which Treats of Melody and Musical Imitation (1881/1966).

Capitalization ( Wuthering Heights )

Capitalization is used for titles, the first word of a sentence, and proper names.

Although Pääbo did his PhD in medical science at Uppsala University in Sweden in the early 1980s, he also studied Egyptology when he was at Uppsala .

You can see more examples on the capitalization page.

These examples were sourced mainly from articles in The Conversation: Who invented music? ; Why does nature create patterns?; Gravity; Pizza; How has the inside of the Earth stayed as hot as the Sun’s surface for billions of years?; Seashell sounds; Are firstborns really natural leaders?; Apex predators; Exxon scientists and climate change; Rousseau and Emile; What makes us human;

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