Scientific English as a Foreign Language
Answers to Lesson of April 4, 1998
Colons and Semicolons

Colons (:) are used to indicate the beginning of a list. Use two spaces after a colon.

You could present the same information in the following way.

In the latter example, no colon was used. In the former, I used a colon as a way of saying "Attention! Here comes the list!" The information after the colon is specific. The phrase before the colon prepares you for the list. The latter example has the same information content as the former. There is more emphasis on what the list items are if a colon is used.

Last week, I said

"Do not use commas to join two independent clauses; semicolons (;) or periods are preferred.

There is one other situation in which to use semicolons. If you have a long list where each item is composed of several different things, then separate the items with semicolons.

Scientists frequently use colons and semicolons in figure captions.

Punctuate the following using commas, semicolons, or colons. Optional punctuation is indicated by parentheses.

1. Eat, and drink this tea.
2. Listen, and write an essay.
3. Do the experiment(,) and write a paper.
4. Do the experiment; write a paper.
5. We used the following approach:  we first laid the DNA on the substrate and let it dry; then we used an AFM to image the DNA and determine its conformation; the image was then used to generate data; and(,) finally(,) the Flory exponent was determined.
6. I need three items:  methanol, acetone, and distilled water.

If the label on the cable on the table at your house
Says the network is connected to the button on the mouse,
But your packets want to tunnel on another protocol,
That's repeatedly rejected by the printer down the hall,
And your screen is all distorted by the side affects of Gauss,
So your icons in the windows are so wavy as a souse,
Then you may as well reboot and go out with a bang,
'Cause as sure as I'm a poet, the sucker's gonna hang!

-author unknown

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Created 30 April 1998, by Nancy Burnham and Fred Hutson.