Today in class my students all became water droplets. They lived their little water droplet lives traveling through the water cycle.
Though it is probably a little too "young" for my students it is a game we love. You can find it here.
You set up different stations around your room - clouds, groundwater, animal (my students' favorite), ocean, lake, and a few others. I randomly assign students to each station.
They roll a number generator and find the coinciding number on their station. It tells them what happened to them.
For example - and this is why the animal is their favorite - If they start in the animal and roll a one the directions say "Water is excreted onto the soil through feces and urine."
Gotta love those 7th graders!
Some years I set a timer and they go through as many stations as they can during that time. Other years I have them go through x number of stations no matter how long it takes.
They carry paper with them recording their life and all the station they visit.
When they are finished with that part, they can do a variety of things. Again I vary it from year to year. They can write a creative story about their life using vocabulary such as evaporate and condense. They could create a comic strip about their life. There are lots of possibilities.