Understanding and Demonstration of Aperture

Aperture is the hole within the lens that allows light to travel through. How much light travelling through can determine the brightness of the photo. Aperture is like a pupil; which can open and close to allow more or less light to enter the lens. A large aperture will allow a lot of light into the lens, resulting in a much brighter photograph and a low aperture will make a photo darker. Both a small and large aperture can have benefits dependant on what kind of photograph is wanted.
In a dark environment, a large aperture will be needed to be able to pick up on what is in the photograph, similar to when your pupils dilate when it is dark.
Aperture can affect depth of field. This is because a large aperture increases blurs and a small aperture reduces them. Large aperture results in a shallower effect in photos.
Apertures are described in the terms of f-numbers. For example, f/11 is a small aperture, and f/3 is larger. The larger the number, the smaller the aperture (confusing).