This idea will get your students working hard using all the controls on their cameras.
Depth of Focus
Take photos using apertures from say f2.8 to f16 to get minimum depth of field
to maximun DOF.
Shutter Speed
Try the slowest and fastest shutter speed settings and produce images depicting these speeds.
Focal Length Again take two sets of images that use the shortest to longest focal length settings.
Angle of View
Get students to take images from different points of view such as from high up or from ground level.
Light
This may take a while to do because it depends on the weather and time of day.
So try for High Key and Low Key. Try photos at night and in very bright light.
Explore a Topic
This will also take time to do. Try photographing a subject near home many times. Try taking the scene at dawn/ dusk for high/ low levels. Different compositions