One thing in photography that intimidated me was Aperture. The word itself seems scientific and foreign to me.
One thing I have tried to do in my life since Kindergarten was to understand those things which scare me. I have done it with math, physics, spiders, and now the inner workings of a camera. I'm not claiming to be a genius in all these subjects but I feel that the best way to get over feelings of self doubt and ignorance is to face something head on that scares the crap out of you.
OK well enough life lessons, let's get to the Aperture!
Basically what I have found is that the wider the Aperture (which means its letting in more light as a whole) the blurrier the background is (which can be very pleasing) and the smaller the Aperture the more in focus the background is. I spent some time pondering why exactly that is. To some people with a logical brain the answer may be obvious. But I am an abstract thinker so it takes me a few minutes :)
Here is an example of a wide open Aperture on a sunny beautiful summer day:
Notice that the Goldenrod in front is sharp and crisp and the stuff in the background looks kind of mushy and soft.
Now here is an example of a narrow Aperture opening, same scene, different orientation:
What I feel is that when you let more light in the camera is only able to record what is directly in front of it in the short time the shutter is open, leaving the stuff in the back to be present but not as sharp. When there is a more focused amount of light coming in the camera is able to "see" more without being overwhelmed. Aperture Priority (Av) is one of my favorite settings. There is a lot you can do with it and it can bring emotion to your photos depending on subject and lighting!