1. Green and Gray Structures By Mary Erickson, Ph.D., and Sarah Chelton, Arizona art teacher

2. All around us are structures. Structures are made of parts put together in an organized way. Some structures are formed through natural processes, like growth, erosion, or by animals or insects. Other structures are designed and built by people.

3. Natural structures are often green, like plants, but not always.

4. Structures built by people are sometimes gray, like metal and cement, but not always. Tempe Center for the Arts from pedestrian bridge Intake towers in Lake Mead at Boulder Dam Walt Disney Concert Hall, Los Angeles

5. Are the green structures in this photograph natural or human made? Are the gray structures natural or human made? Canal bridge at Arizona Biltmore, Phoenix, AZ

6. Is the gray structure natural or human-made? Is the green structure (not the leaves) in this photo natural or human-made? How can you tell?

7. Sometimes people and nature make similar structures. The cement bridge arches were built by people. The stone arch was formed by the natural erosion of wind and water. Mill Avenue Bridge, Tempe, Arizona Canyonlands National Park, Utah

8. How are the parts of both these structures organized? In parallel rows? Radially around a center point? In a pyramid form? At right angles?

9. These are similar natural and human-made structures. How are the parts different? How is the organization of parts different?

10. Match a natural structure with a human-made one. Identify both and explain how they are similar.

11. Match a natural structure with a human-made one. Identify both and explain how they are different.

12. Human-made structures and natural structures contrast, merge and co-exist. Frank Lloyd Wright, Norman Lykes House, 1966, Phoenix, AZ

13. Describe how natural and human structures are organized in these photos.

14. People have severely trimmed the small branches of this tree. Its parts are organized as much like a bunch of balloons as like a natural structure.

15. Metal structures control the growth of the young trees on the right. How do the trees resemble human-made umbrellas? How do they resemble the structure of natural flowers? Amsterdam, Netherlands

16. The Navajo Electrical Generating Plant was built among the natural canyons and buttes of northern Arizona. Why do you suppose some people think that building the plant was a good idea and others think it was a bad idea?

17. Some artists make artworks inspired by human and natural structures. Karen Jilly Urban Fringe oil on wood Mohammad Reza Javaheri The Orange Tree & Its Double monotype prints

18. Your follow-up lesson challenges you to use mixed media to make your own visual statement about relationships between natural and human structures. What structures do you think you might bring together? How would the structures relate to each other?

19. These human-made structures seem to dominate the natural structures around them. Very Large Array, Socorro, NM Mike O’Callaghan-Pat Tillman Memorial Bridge Between Arizona and Nevada

20. With the passing of time, natural structures sometimes overcome structures built by people. Dougga, Tunisia Goldfields, AZ,

21. Do these human-made structures and natural structures seem to complement each other? Norwegian Costal Highway Montezuma’s Castle, Camp Verde, AZ

22. You are invited to visit the Green and Gray exhibition at the Tempe Center for the Arts. Discover how artists have been inspired by relationships between human-made and natural structures. Jonathan Howard Worn Out Life mixed media