This week, you will look at some of the non-vegetative elements of our selected site. Air and water are present, but this week you will focus on the presence of light, writing a short description of the categories of light you experience in your area.

Light and shadow are noticeable when the sky is cloudless, for shadows are deeper and sun brighter then. But even in the diffused light of a cloudy day, there are still shadows and light, though we often ignore them.

This week, plan several-at least two, but three or even more are better- observational visits to your site, preferably at different times of the day. On your first visit, observe where the light falls most fully, and where the shadows are deepest. Notice the varying colors of the vegetation when it is sunlit or in shade. Notice whether the shadows are sharp and well defined, or soft and diffused.

In your other visits, see when and where there are changes as the earth moves in relation to the sun. Are there some areas that become sunnier, some shadier? Are the colors different at different times of day? Do you see any pattern to the way the plants are grouped, in terms of the available sunlight?

Do not limit yourself to looking down at the ground as you do your observation. Look at the sky as well. Note the heaviness and shape of any clouds you see. Notice the color as well, both of the sky and of the clouds. You need not worry about whether you know the technical terms for cloud formations; just look carefully at their shapes and colors.

The paper you will write is a classification paper, one that places experiences into categories. Freewrite for awhile, describing the various kinds of light and shadow you noticed in your space. Try to be as specific as possible about the differences you discerned.

Then, find a way to group the varying experiences you had; you need at least two categories, but may offer as many more as you wish. Do not use already- existing categories, ones which scientists or artists have employed; make up your own, ones that reflect your own experience. Use your thesaurus to search for labels for your categories. You may notice, for instance, that light in your area is soft sometimes, sharper at others. Ask yourself if the word "soft" is the best way to describe what you see. Would any of these be better? Gentle, plastic, softened, relaxed, smooth, silken, creamy, feathery? A heavier, more shadowed day could be called leaden or dark, hazy or dull, depending on how you experience the conditions of light and shadow. The choice of words is yours. You may, in writing, decide to describe the sky or the ground, or both.

Once you have sorted your experiences into categories and given them names, write a taxonomy-a description of the categories-and describe the light and shadow as vividly as possible. You will notice that you will use analogies, comparing what you see to something else: a "feathery" cloud, for instance, compares the white in the sky with something on a bird's wing. This is how descriptive language works; we constantly compare things to other things, seeking to evoke pictures in our readers' minds.