They SAY that moss usually grows on the north side of trees, but this is just because the north side tends to be out of the sun during the most drying part of the day — leaving more moisture behind for mosses to grow.
Investigate this phenomenon. Go into nearby woods and fields and compare the north and south sides of objects. Don’t limit yourself to trees. Compare the north/south facing sides of large rocks, manmade objects, and geological features such as hills and outcroppings. Is there really a large difference between the south-facing and the north-facing sides?
Take a notebook with you and really search for details. Look at the collection of leaf litter, the distribution of large and small plants, even the temperature of rocks and their surface texture. Record as many details as you can, perhaps having one two-page spread of your notebook display comparisons of north (on one page) and south (on the facing page) sides. Be brave and make a few sketches of your observations, and add to them later on future outings.
Web pages to help: