Handle for scissors is good example. Provide examples of good and bad mappings. Relationship between aspect of the interface and the real world. Turning steering wheel is good mapping. Provide examples of good feedback.
Feedback closes loop on interaction.
Give an example of when a reminder fails because one of the components is missing. Name a type of forcing function and give an example of that type. A form of physical constraint. Actions are constrained so that failure at one stage prevents the next step from happening. Keep operation active, prevents stopping prematurely.