Three Discs, One Lacking Lesson Plan

An Introduction to Public Art in Philadelphia for 4th/5th Grade

TOPIC: An Introduction to Public Art in Philadelphia for 4th/5th Grade


1. Goals: To acquaint students with examples of public art in Philadelphia, and create an awareness of the wide range in form that public art can take.

2. Objectives:
A. The students will have a basic understanding of the Calder family’s presence in Philadelphia’s public art.
B. Students will have a basic understanding of Three Discs, One Lacking, how it was created, and what it aims to represent.
C. Students will be introduced to the many forms that public art can take.
D. Students will have a basic understanding of place, and how place can effect the outcome of how a work is perceived.


Three Discs, One Lacking is a sculpture by Alexander “Sandy” Calder, an American artist famous for creating mobiles and large-scale sculptures. Before becoming a sculptor, Calder studied engineering. However, he came from a family of prominent artists in the Philadelphia area: his grandfather, Alexander Milne Calder, was the artist who created the William Penn statue atop Philadelphia’s City Hall, and his father, Alexander Stirling Calder, created Swann Memorial Fountain in Logan Square. Though Calder came from a family of sculptors who worked in the figurative tradition, he chose to work more abstractly and with more contemporary materials. Instead of making cast bronze or carved stone objects like his father and grandfather, he used industrial steel and rivets to form large abstract works. Many of his works reflect the materials you find in the city surrounding them.

Riveting is a technique that has been used for centuries in industrial, as well as artistic creation. A rivet is typically shaped like a mushroom, with a skinny base and round wide head. In this technique, a hole is drilled through two pieces of metal and the skinny base of the rivet is placed through both pieces of metal. The head sits flush against one side of the joint, and the extra slack of the base of the rivet hangs out the other side. This slack is then pounded so that the extra material flares out, creating another wide flat head. The two pieces of metal forming the joint will be tightly sandwiched between the two heads.

Calder was famous for stabiles (works that are stationary) and mobiles (works that incorporate movement). While his mobiles physically move, his stationary work uses formal elements (line, shape, space), to create visual movement. Three Discs, One Lacking (a stabile) begs the viewer to walk around it, crawl under it, stand over it, and watch it shift and change, just like the city shifts and changes around it.


Have the class watch the Association for Public Art’s online audio slideshow for Three Discs, One Lacking


1. Have the class look at the sculpture/image. Begin by encouraging general conversation, for example by asking (2 mins):
•What do you see?
•What is being depicted? Is anything being depicted?

2. If the class is familiar with the elements of design, discuss how these elements are used in the sculpture (3 mins):
•Is a form depicted? (non-figurative abstract form)
•Where are the visual points in the sculpture? (the two circles, the points touching the ground, etc.)
•What are the movements depicted by the sculpture? (curving, circling, etc.)
•Color, texture, plane, value also could be discussed.

3. If the class has previously looked at other public works, compare the goals of the sculptures and formal techniques utilized to achieve these goals (3 mins). (This work can be paired with the lesson plan for Kopernik or Iroquois.)

4. This sculpture has been intentionally placed between the works of Calder’s father and grandfather. Use this opportunity to discuss the many variations of public art (5 mins):
•How do the forms of the Calder family sculptures vary? (Some are figurative, some are abstract)
•Is there a particular person being depicted in each sculpture? (William Penn, allegorical figures representing Philadelphia’s rivers)
•Do you think that one form of public art is more successful than the other?


Construction Paper
Tissue Paper
Colored Pencils / Markers
Photos or maps of locations in your area

After discussing the Calder family of artists and their work, it should be clear that public art can take many forms. Have your students create a “public artwork” that they would like to see in their own community. Why? What would it look like? How would it be made? On a map or photo of your community or neighborhood, have students place their works at the locations where they would like to “install” them. Encourage the student to discuss why the selected site would be appropriate for each sculpture.

VI. CLEAN UP (5-10 mins)


Arts and Humanities

9.1.3.A: Know and use the elements and principles of each art form to create works in the arts and humanities.

9.1.3.B: Recognize, know, use, and demonstrate a variety of appropriate arts elements and principles to produce, review, and revise original works in the arts.

9.1.3.C: Recognize and use fundamental vocabulary within each of the arts forms.

9.2.3.A: Explain the historical, cultural, and social context of an individual work in the arts.

9.2.3.H: Identify, describe and analyze the work of Pennsylvania artists in dance, music, theatre and visual arts.

9.1.3.I: Identify arts events that take place in schools and in communities.


1. Was the student attentive during video/historical background?

2. Did the student participate in class discussion? Did this participation reflect attentiveness during the video? Did this participation reflect application to previous lessons?

3. Did the student participate in the activity?

4. Was the student respectful to other students’ opinions and work during the lesson?


1. This lesson can be paired with the lesson Introduction to Public Art

2. This lesson can be paired with the lesson for Kopernik. Related themes include:
•similar formal elements
•abstract public art
•metal sculpture
•comparison of formal elements
•site-specific works

3. This lesson can be paired with the lesson for Iroquois. Related themes include:
•similar formal elements
•similar means of building construction
•abstract public art

The Calder Foundation: