Learning Objectives 

Students will: 

• Explain the functions and parts of a lever.
• Compare the differences between the three types of levers.
• Describe potential and kinetic energy.
• Analyze and interpret the mobiles of Alexander Calder.
• Apply mathematical, science, and engineering concepts. 
• Build and design a simplified mobile.
• Test the balance objects by changing and moving objects on a lever (simplified mobile).

Standards Alignment

National Core Arts StandardsNational Core Arts Standards

Common Core State StandardsCommon Core State Standards

Next Generation Science Standards Next Generation Science Standards 

Recommended Student Materials

Editable Documents: Before sharing these resources with students, you must first save them to your Google account by opening them, and selecting “Make a copy” from the File menu. Check out Sharing Tips or Instructional Benefits when implementing Google Docs and Google Slides with students.

• Vocabulary: Balance & Motion
• Classes of Levers
• Lever Closed Sort
• Balance Capture Sheet

Websites

• The Lever
• Levers: Simple Machines
• VIrtual Mobiles
• Calder’s Work: Hanging Mobile
• Calder’s Work: Standing Mobile
• Calder’s Constellation, 1943 mobile
• Work of Alexander Calder

Additional Materials

• Ruler
• String
• Tape
• Scissors
• Pens
• Paper cups
• Small objects or manipulatives

Teacher Background

Teachers should build or purchase a mobile to use for demonstration. Teachers should be familiar with Alexander Calder, Types of Levers, and Kinetic and Potential Energy.

Student Prerequisites 

Students should be familiar with simple machines and should have basic knowledge of potential and kinetic energy.

Accessibility Notes

Modify handouts and mobile design resources as needed. Allow extra time for task completion.

Engage

1. Introduce a simple machine called a lever. Explain that levers are often used to do work with less effort, such as lifting heavy objects. Draw an image of, or visit, a see-saw on the playground. Use the see-saw to point out, or demonstrate, the following Vocabulary: Balance & Motion.

2. Discuss the three Classes of Levers. Act out or use props to demonstrate each type if necessary.

3. Have students explore the three types of levers. In pairs, students should continue to read The Lever and investigate Levers: Simple Machines. 

4. Continuing to work in pairs, have students complete Lever Closed Sort. If possible, bring in objects or photos that correspond to the ones listed on the “closed sort.”

Build

1. Explain the relationship between levers and mobiles. Explain that a mobile is a cascade of levers. Each lever is suspended from above and has objects or other levers suspended from its ends.

2. Show the sample mobile you made to the class. Point out how the mobile is made up of a series of levers in equilibrium. Levers and objects hanging from mobiles are placed so that all parts of the mobile are balanced. Point out the fulcrums and arms of the levers.

3. Demonstrate potential and kinetic energy on a mobile. Explain how a mobile has potential energy when it is still. Demonstrate and discuss how potential energy is converted to kinetic energy by lightly blowing on the mobile and vice versa when there is no air current.

4. Have students explore the concepts behind building a mobile. Students should create virtual mobiles by arranging and rearranging objects to try and find a balance.

5. Project or display images of the mobiles of Alexander Calder. Show images of Calder’s Work: Hanging Mobile and Calder’s Work: Standing Mobile. Explain that mobiles are kinetic sculptures — three-dimensional works that include moving elements and a balance of objects. Note how the objects appear to float in space.

6. Discuss how mobiles are a form of art. Ask students, what do you like or dislike about Calder’s work? What comes to mind when looking at the mobiles? 

7. Show Calder’s Constellation, 1943 mobile, but do not reveal the title of the work. Ask students, what do you think the title of this piece is called? Why? After some discussion, reveal the title and ask students, how was Calder effective or ineffective in communicating a constellation?

8. Have students explore the Work of Alexander Calder. Explain to students that Calder’s mobiles were informed and inspired by his knowledge of physics, mathematical concepts, the cosmos, and astronomy. Before Calder enrolled in art school, he had received his mechanical engineering degree, a decision influenced by his fascination with construction, mechanical apparatuses, and machines.

Apply

1. Build the arm of the mobile. Students should tie a string around the middle of a ruler (this may need to be taped to the ruler to hold it in place). Tie or tape the loose end of the string to a sturdy place, such as the edge of a desk, so that the ruler is dangling in mid-air.

2. Attach cups to the mobile. Using scissors or a pin, poke a hole in the rim of a paper cup, insert a string through the hole, and knot it so that end stays in the hole. Do the same to the other paper cup (using the same size string). Tie the loose ends of the strings so that each cup is hanging from a different end of the ruler.

3. Balance the mobile. Place various amounts of small objects in the cups in an effort to find the equilibrium. Encourage students to experiment with the position of the fulcrum, the weight of the loads in the paper cups, and the lengths of the strings.

4. Make observations. Students should make notes on the Balance Capture Sheet as they improve and test what happens as they alter factors in their mobiles.

Reflect 

1. Engage students in a “Gallery Walk” to make scientific observations and discuss the design of the mobiles. Regroup as a class to share out observations, questions, and conclusions. 

2. Assess students’ knowledge of balance with one of the following writing prompts: In the design process, what did it take to balance the mobile? How did changing the position of the fulcrum or the weight of the loads affect the mobile? Students can use their Balance Capture Sheet as a reference tool.