It's or Its? What's the difference?
Confusing "its" and "it's" is one of the most common mistakes I see in amateur writing. I will try to explain the difference between these two words so that you'll never again have to wonder if you used the correct one.
You might be tempted to lay all the blame for your confusion on the apostrophe, but it's not really the apostrophe's fault. Let me tell you a story.
Long ago the Apostrophe got a job filling in for missing letters wherever there was a contraction. A contraction is when two words are smashed together to form one word.
For example when you put "does" and "not" together, you squish out the "o" and you get "doesn't."
Other examples are:
would + not = wouldn't
they + will = they'll
let + us = let's
it + is or it + has = it's
Did you catch that last one? Good. You use "it's" when there's a contraction. There's no messing with the contraction rule; it's concrete.
If you take two words, slap them together to make one word while squishing out some of the letters, you must always use an apostrophe to take the place of the missing letters.
Now, back to my story. As often happens when someone does their job extremely well, management decided the Apostrophe needed something else to do. They decided that, not only would the Apostrophe appear every time there was a contraction, he should now also show possession of something.
For example, if the cock belongs to Joe, you write:
Joe's cock
Other examples:
Jane's luscious tits
the Master's whip