I want to introduce to my class to the derivative, but I am still searching for a good, realistic context that isn't too hard to understand, without seeming to be contrived. Do you have an ideas for that?
Edit: I want to use a problem that needs to be solved by the use of the first derivative, so that the students come to a preliminary understanding of the derivative as representing the instantaneous rate of change.
Further edit: I am introducing students aged 17-18 years, to the first derivative of a function of one variable. So I would say that my question is about teaching high-school students. I am looking for an example to demonstrate the first derivative that has is roots in the everyday life of the students. [Consolidation of a comment from the author of this post.]