Colons are used to introduce items in a list. For example, [reading from the slide]: “I am teaching the following classes next semester” colon, and then you go on to list the classes.
But I want to bring you down to this tip down here. You only use colons when the list does not fit into the sentence’s construction. If the sentence flows naturally, if the list fits naturally into the flow of the sentence, you don’t need to use a colon. I wouldn’t use a colon in this sentence, [reading from the text box at the bottom]: “The Jackson’s three sons are Peter, Sean, and Mike” right? That sentence, it all flows together very nicely. I would use a colon here, however, [reading from the slide]: “the Jacksons have three sons: Peter, Sean, and Mike.”
Now this colon, you can hear I sort of paused when I was reading this. And that’s what this colon indicates, you should take a pause, and then after this colon is where I’m going to list these different elements so, only use a colon when the list doesn’t fit naturally into the sentence.
You can also use a colon to elaborate on a statement. For example, [reading from the slide], “My classmates and I all agree: we will need to reread chapter 3 before the test this week.” In this sentence, I’m elaborating, I’m explaining what my classmates and I agree.
[Source: Walden University. https://academicguides.waldenu.edu/c.php?g=465757&p=3437922 ]