Bill Nye: Phases of matter video sheet. Very easy for my 7th grade EC classes, it's multiple choice answers, the last 3 are short response. This way they get a chance to watch the video and not spend all of the time on reading and answering the follow along question.
Some question topics include
The hydrological cycle
How molecules move when energy is added/removed
How the earths water has been recycling for 3 billion+ years.
Hard time finding the video to stream try looking on dailymotion