I added several new icons this year with my kids. One of them was "Over Time". I really thought it would be easy for them to grasp (they got ethics right away). Nope. It took them awhile to really understand. At first we did an ice cube over time-starts off as water, freezes then melts. We had many Social Studies objectives to compare past and present; so we looked at cars, planes, cities, etc.
We've been talking about Civil Rights a lot and I decided to have them write about how Civil Rights have changed over time. I think they may finally be getting it. My favorite is the one that says in the future she'll be the President! With that student it just may happen.