Another element of the photographic triangle which I talked about in my article The exposure triangle is Shutter Speed which relates to the amount of time which the shutter remains open to let light onto your sensor, it is measured in time ranging from 30 seconds or more to 1/8000th of a second or less.
Again shutter speed can be measured in stops and changing your shutter speed from one stop to the next will result in the doubling or halving of the amount of light let into your camera.
Here are the stops for shutter speed.
1/8000, 1/4000, 1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1 sec, 2 sec, 4 sec, 8 sec, 15 sec, 30 sec
Faster shutter speeds allow you to freeze fast moving action like sports or wildlife and capture sharp shots. Slower shutter speeds are useful in poorly lit scenes if you need to allow more light on to your sensor to get a properly exposed shot. They are also great for artistic shots of scenes which you can see in a number of my images in the gallery