Key points from the video

Punctuation 2

• This is our second lesson about punctuation.

• This one goes beyond commas to look at punctuation marks such as colons, semi-
colons, and quotation marks.
• As we said in the first lesson, punctuation in English is a mix of hard rules and stylistic
choices, which can make it very tricky.
• So, let's take a look at some of these rules and choices that you are likely to encounter in
your own writing.

• Look at these three sentences and decide which of them

• is punctuated correctly.
• (Please keep in mind that it might be more than one that is correct.)

• Example 1
• The Earth’s atmosphere consists of four main layers, the troposphere, the
stratosphere, the mesosphere, and the thermosphere.

• The Earth’s atmosphere consists of four main layers; the troposphere, the
stratosphere, the mesosphere, and the thermosphere.

• The Earth’s atmosphere consists of four main layers: the troposphere, the
stratosphere, the mesosphere, and the thermosphere.

• What we're looking at here is the use of colons and lists.

• The last one is the correct one.
• The reason is that we have an independent clause followed by a list, and that is exactly
where we use a colon: after the independent clause, and before the items in the list.
• We do not use a comma there, and we do not use a semi-colon.
• A colon is the correct punctuation to use in this scenario.

• Note that we have commas in between the items of the list.

• If you have very long list items that are more complicated and maybe have embedded
clauses within them, this one for example, you can separate them with semi-colons.
• In the first bunch of sentences we have here, it's a very simple list with simple items,
• four simple items, and it's fine to use the comma as there's no confusion there.
• But in this second one, if we just used commas it would be very difficult to tell what the
items in the list were, so the semi-colon provides a little bit of extra separation among the
list items.
• The Earth’s atmosphere consists of four main layers: the troposphere, where humans
live; the stratosphere, the lower part of which is where airplanes fly; the mesosphere,
where temperatures drop as low as -90 degrees Celsius; and the thermosphere, which
contains many satellites orbiting the Earth.

• Example 2
• An accurate map is the first tool an archeologist needs; only when the site has been
thoroughly surveyed can excavation begin.

• An accurate map is the first tool an archeologist needs. Only when the site has been
thoroughly surveyed can excavation begin.

• An accurate map is the first tool an archeologist needs, only when the site has been
thoroughly surveyed can excavation begin.

• What we're looking at here is how to separate independent clauses.

• As we discussed in the first punctuation lesson, we do not use a comma to separate
these.
• This last one is incorrect, because it separates two independent clauses with a comma.
This is called a comma splice, and it is always wrong.

• Your options instead are to use a semi-colon, as in the first sentence, or to use a period
and start a new sentence: essentially make your one sentence into two sentences.

• Example 3
• Watson and Crick, aware that their discovery is revolutionary, refer to their theory of the
double helix structure as “radically different.”

• Watson and Crick, aware that their discovery is revolutionary, refer to their theory of the
double helix structure as “radically different”.

• Watson and Crick, aware that their discovery is revolutionary, refer to their theory of the
double helix structure as “radically different” (1953, 737).

• It may take a minute to realize which punctuation mark we're looking at here.
• The concern here is how to punctuate quotations.
• Before we describe these citation rules, we would like to remind you that if you
encounter any ambiguities regarding these rules, consult your citation guide.
• The rule here is that if you don't have a citation for your quotation, periods go inside the
quotation marks; if you have a citation, periods have to go outside both the quotation
marks and the citation.
• The middle one is wrong, because the period is outside of the quotation marks and
there's no citation; the first one and the third one are both correct.
• Now you know how to punctuate quotations at the end of your sentence.

• The next question is, how do you punctuate them in the middle of your sentence?
• If you have a citation followed by a comma, the rule is the same as for periods.
• If you do not have a citation, put the comma inside the quotation marks; if you do have a
citation, put it outside both the quotation mark and the citation.

• Example 4
• Watson and Crick, referring to their theory of the double helix structure as “radically
different,” are aware that their discovery is revolutionary.

• Watson and Crick, referring to their theory of the double helix structure as “radically
different” (1953, 737), are aware that their discovery is revolutionary.

• If you have a colon, a dash, or a semi-colon after your quotation, then they always go
outside the quotation marks, as in these examples.

• Example 5
• Watson and Crick’s theory was “radically different”: a double helix structure.

• Watson and Crick’s theory was “radically different” - a double helix structure.

• Watson and Crick’s theory was “radically different”; their discovery was revolutionary.

• If you have a quotation that you need to add, subtract or change information in, here's
how you can do it: you can use these square brackets.

• Example 6
• Watson and Crick revolutionised the study of genetics by “put[ting] forward a radically
different structure” for DNA

• Watson and Crick describe DNA as having “two helical chains each coiled around the
same axis […].”

• “[T]wo helical chains each could round the same axis” form the structure of DNA,
discovered Watson and Crick.
• In the first sentence, we have used these square brackets to change the word form to
make the sentence make sense.
• In the second one we have excerpted information from the quotation and so we put this
dot-dot-dot called an ellipse inside the square brackets to show that you have removed
information from the quotation.
• In the last sentence, you have changed a letter in the sentence to a capital letter so you
can put the quotation at the beginning of your sentence and it is correct. So any change
or addition or subtraction that you make from your quotation as it's written in your source
should be used with square brackets so your reader knows that you've made a change.

• Example 7
• Black holes, objects whose gravitational pull is too strong for light to escape, are
formed when massive stars collapse.

• Black holes - objects whose gravitational pull is too strong for light to escape - are
formed when massive stars collapse.

• Black holes (objects whose gravitational pull is too strong for light to escape) are
formed when massive stars collapse.

• Ok, for these sentences we're looking at how to punctuate non-essential information in
the sentence.
• So, information that's nice to know, extra information that you'd like your reader to have,
but not necessarily essential for knowing what you mean in the sentence.
• In fact, all three of these sentences are correct as they are written.
• These are three different options for how to punctuate this kind of non-essential
information.
• You can use paired commas, you can use two dashes, or you can use parentheses.
• All of them are perfectly fine.
• Everybody has different ideas about the stylistic effects of these three.
• Many people think that the dashes put more emphasis on the non-essential information
and make it stand out more from the rest of the sentence.
• It depends on how much emphasis you want to put on that non-essential information.

• Example 5
• Copernicus, Galileo, & Newton are three of the best-known founders of modern
physics.

• Newton’s formulation of the law of gravity has made him one of the most famous
physicists in history, but his discoveries would not have been possible without
Copernicus/Galileo.

• Galileo’s promotion of heliocentrism was considered so radical, he was sentenced to

spend the rest of his life under house arrest!
• All of these three sentences are neither correct nor incorrect.
• These are perfectly fine the way they have used these three punctuation marks.
• The first one is called an ampersand, it means 'and.'
• In the second one there's a slash, and in the third one there’s an exclamation point.

• The issue here is register, which means how formal or informal your text is.
• If you're writing an academic text, then try to avoid symbols like these and abbreviations.
• If you are bothering to write a long, beautiful, polished academic text, you might as well
take the time to write the word 'and.'

• In the case of the third sentence, the exclamation point just makes the sentence sound a
little bit too dramatic.
• It's possible that there are places in your text where you will want that kind of drama, but
it's unlikely that this is something that will come up, and you should certainly try to be
sparing with your exclamation points, if you use them at all.