Such an exercise would teach students the basic concepts involved in making any map. A homework idea might be collecting boulders, cobbles, pebbles, sand, silt and clay-sized material at beaches or streams. The difference is in the particle size. You can use different sizes of sieves for separtation. Watching various grains settle in layers in a jar of water is also interesting.
Water carries fine material in suspension for long distances.
Boulders are usually found near the sediment source areas. Taking pictures of different experiments provides a way of objectively comparing results. Always use a ruler in the field of view to provide a scale which allows you to more quantitatively compare features from one experiment to another. An opportunity for real application of skills is to take an outside hike with a map and figure out where you are exactly. This bears on an important way of geometrically thinking.