Balancing Mobiles
How do balancing forces relate to the engineering and design of a mobile?

In this 6-8 lesson, students will apply mathematical, science, and engineering concepts to experiment with balancing levers. They will learn to classify types of levers to design and build a simplified mobile. Students will explore suspended and standing mobiles by sculptor Alexander Calder and engage in class discussions about the effectiveness of his work.

Lesson Content

Learning Objectives

Standards Alignment

National Core Arts Standards National Core Arts Standards

VA:Cr1.2.6a Formulate an artistic investigation of personally relevant content for creating art.

VA:Cr1.2.7a Develop criteria to guide making a work of art or design to meet an identified goal.

VA:Cr1.2.8a Collaboratively shape an artistic investigation of an aspect of present day life using a contemporary practice of art and design.

VA:Cr2.1.6a Demonstrate openness in trying new ideas, materials, methods, and approaches in making works of art and design.

VA:Cr2.1.7a Demonstrate persistence in developing skills with various materials, methods, and approaches in creating works of art or design.

VA:Cr2.1.8a Demonstrate willingness to experiment, innovate, and take risks to pursue ideas, forms, and meanings that emerge in the process of artmaking or designing.

Common Core State Standards Common Core State Standards

ELA-LITERACY.W.6.2 Write informative/explanatory texts to examine a topic and convey ideas, concepts, and information through the selection, organization, and analysis of relevant content.

ELA-LITERACY.SL.6.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 6 topics, texts, and issues, building on others' ideas and expressing their own clearly.

ELA-LITERACY.SL.6.2 Interpret information presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how it contributes to a topic, text, or issue under study.

ELA-LITERACY.W.7.2 Write informative/explanatory texts to examine a topic and convey ideas, concepts, and information through the selection, organization, and analysis of relevant content.

ELA-LITERACY.SL.7.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 7 topics, texts, and issues, building on others' ideas and expressing their own clearly.

ELA-LITERACY.SL.7.2 Analyze the main ideas and supporting details presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how the ideas clarify a topic, text, or issue under study.

ELA-LITERACY.W.8.2 Write informative/explanatory texts to examine a topic and convey ideas, concepts, and information through the selection, organization, and analysis of relevant content.

ELA-LITERACY.SL.8.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 8 topics, texts, and issues, building on others' ideas and expressing their own clearly.

ELA-LITERACY.SL.8.2 Analyze the purpose of information presented in diverse media and formats (e.g., visually, quantitatively, orally) and evaluate the motives (e.g., social, commercial, political) behind its presentation.

Next Generation Science Standards Next Generation Science Standards

MS-PS3-5. Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object.

MS-ETS1-1. Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

Recommended Student Materials

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Additional Materials

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 .
  1. Discuss the threeClasses of Levers. Act out or use props to demonstrate each type if necessary.
  1. Have students explore the three types of levers. In pairs, students should continue to read The Lever and investigate Levers: Simple Machines .
  1. Continuing to work in pairs, have students completeLever 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.
  1. 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.
  1. 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.
  1. 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.
  1. 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.
  1. 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?
  1. ShowCalder’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?
  1. Have students explore theWork 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.
  1. 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.
  1. 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.
  1. 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 .
  1. 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.