Circus Physics: Conservation of Energy

Type Category
Instructional Materials
Animation/Movie , Interactive Simulation , Activity
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



This resource provides the instructor with a video clip illustrating conservation of energy in a circus routine. Along with the video clip are questions that the teacher can use to hold a class discussion to help students understand how one form of energy can be transformed into another form of energy. After the discussion, there are three activities that can be performed to help reinforce the concepts behind the Law of Conservation of Energy. This review only covers the video clip, discussion questions, and first activity: Rubber-Band Machines. In the activity, students are to create a simple device that will convert elastic potential energy of a rubber band into kinetic energy so as to launch a marshmallow to the highest possible height.

Intended Audience

Educator and learner
Educational Level
  • High School
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

HS-PS3-3 Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.

Clarification Statement: Emphasis is on both qualitative and quantitative evaluations of devices. Examples of devices could include Rube Goldberg devices, wind turbines, solar cells, solar ovens, and generators. Examples of constraints could include use of renewable energy forms and efficiency.

Assessment Boundary: Assessment for quantitative evaluations is limited to total output for a given input. Assessment is limited to devices constructed with materials provided to students.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The instructor will want to explicitly point out that the students need to refine their design until they achieve the maximum possible height from their device. In addition, the instructor will want to have a class discussion about elastic potential energy if it has not already been covered before this activity.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
To more fully address the practice, the students should compare and evaluate their devices with those of other groups.

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
The instructor will need to have a class discussion using the pre and post video questions that the activity provides. These questions will help guide the students to understand the Disciplinary Core Idea.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
To more fully address the Cross Cutting Concept, the instructor could have the students draw energy diagrams and/or calculate the energy before the marshmallow is launched, and when it is at its maximum height. This type of diagram can be modeled first together as a class using one of the examples in the video.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The resource aligns with the NGSS because the students draw upon their prior knowledge of energy conservation, as demonstrated by the circus performer in the video clip, to build a device to launch a marshmallow to the highest height possible. However, the resource could more fully address the NGSS if it required the students to refine their marshmallow launching devices.

  • Instructional Supports: The resource does provide a set of good questions that the instructor can use to conduct a class discussion, but the resource doesn’t provide much guidance for the Rubber Band activity

  • Monitoring Student Progress: The activity provides a series of questions that the instructor can use to hold a class discussion. During the class discussion, the instructor will be able to monitor student understanding. To more fully meet the standards of the NGSS in terms of monitoring student progress, the instructor could create a lab worksheet that requires the students to document their thought processes when designing and testing their marshmallow launcher. This would include having the students perform calculations showing the potential energy and the kinetic energy.

  • Quality of Technological Interactivity: The resource does include a video clip, but it lacks interactivity. The video must be streamed from the internet, and cannot be downloaded.