I hesitate to agree with you because this (website) is a nice interactive presentation. But it depends on the audience and more the depth of result required.

I hesitate to agree with you because this (website) is a nice interactive presentation. But it depends on the audience and more the depth of result required. If I was to introduce calculus to non-mathematicians, I'd use almost no maths at at. Not even symbols! I'd use area and slope, with specific examples - probably just distance, velocity and acceleration. I think you'd be able to reveal the magic relationship between slope and area with just that.