about affordance
Explanation of affordance
According to James Gibson affordance is a possibility of human behaviors which is offered by environment. For example a stone with proper height and smooth surface can provide human a possibility to sit.
The characteristic of affordance
one object have several affordance. In the meantime, these affordance are exist at same time without primary and secondary point. For example, a book can be read, and we can write note on it too.
Affordance can be subjective and objective too. It is objective because it can not be change by human will. It is subjective, because it will be illogical, if a possibility of behavior not come from human or animals.
Affordance can be effected by different subject. For example, a stone can be use as a weapon by human, but animals can not be offered.
Example
A pen can provide adults a affordance of writing, at the same time it can open a package as a knife, or rough measure length as a ruler, these affordance is decided by the physical properties of the pan. The affordance of object have a strong connection with human. For example，to adult pen have the affordance of writing, but for baby who do not understand the usage of pen, it do not exist. Sometimes the psychological factors can impact the affordance, when we need to open a package, we use pen as a knife.
Affordances of an iPad
Reading books ( screen, the size of ipad is similar with a book)
Watching movies ( screen, the shape of Ipad is similar with television)
Listening music ( speaker, headphone jack)