For the year 7's it is often the first time they have done much colour theory. It is more of a refresher for the year 8 and 9's. The practical task they do will change every year so they don't do the same project more than once.
My year 7's main task is a primary colour collage (photos coming)
My year 8's made a secondary colour collage (no photos sorry).
My year 9's complete a colour wheel as creatively as possible. (photos coming)
I have pasted images below of a few of the handouts I use with my students. Feel free to use these with your own classes.
I use the sheets below in my year 8 class.
The sheet below is one I often do with the year 8's as a bit of a fun fill in activity.