Gravity and Orbits

Noah Podolefsky (lead designer), Emily Moore (lead), Kathy Perkins, Trish Loeblein, Sam Reid (lead developer), Jon Olson (developer), Chris Malley (developer) and John Blanco (developer)
Type Category
Instructional Materials
Interactive Simulation
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.



Gravity and Orbits is an interactive simulation that investigates the effect of gravity on orbital paths. Users are given the option of investigating four scenarios: 1. star and planet, 2. star, planet and moon, 3. planet and moon, and, finally, 4. planet and satellite. In each case, users can change the size of the objects and the distance between them. Users can also elect to switch gravity on or off. Two screen choices, a Cartoon or a To Scale version, are offered for each scenario. Several documents are available for downloading: a 5 page FAQ for teachers (listed as Teacher Tips), a TeacherNotes file, a lesson plan and a 39 page scripted Teacher's manual produced by UTeach Outreach at The University of Texas at Austin. The TeacherNotes file can be downloaded at: The lesson plan and manual, which are organized around 5-E and include an introductory activity,  probing questions, student responses and potential misconceptions, are available at:  In addition, several teacher-submitted activities designed to support the middle school classroom are available.


Intended Audience

Educational Level
  • Grade 10
  • Grade 9
  • Middle School
Access Restrictions

Free access with user action - The right to view and/or download material without financial barriers but users are required to register or experience some other low-barrier to use.

Performance Expectations

MS-ESS1-2 Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system.

Clarification Statement: Emphasis for the model is on gravity as the force that holds together the solar system and Milky Way galaxy and controls orbital motions within them. Examples of models can be physical (such as the analogy of distance along a football field or computer visualizations of elliptical orbits) or conceptual (such as mathematical proportions relative to the size of familiar objects such as students' school or state).

Assessment Boundary: Assessment does not include Kepler’s Laws of orbital motion or the apparent retrograde motion of the planets as viewed from Earth.

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

Comments about Including the Performance Expectation
Gravity and Orbits allows students the opportunity to investigate the role of gravity on orbital paths within our solar system. Students are active participants in the simulation since they can manipulate two variables in each cartoon scenario: the size of the objects and the distance between them. Students are not developing their own model; rather, they are using pre-designed scenarios to investigate the Disciplinary Core Idea. The concept of gravity within galaxies is not addressed.

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
In Gravity and Orbits, students are using, not developing, a model to explain the force of gravity in our solar system; however, since students can change variables, they are active participants in the simulation. Teachers should encourage students to develop questions prior to running scenarios in order to prevent the session from becoming a crash and burn video game experience. By posing specific questions, students can gather data in a more structured way. Teachers should caution their students that only one variable should be changed in each run of the simulation.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
By using this simulation, students can investigate how size and distance between objects affects both gravity and orbital paths in our solar system. By manipulating these values, students can visualize how changes to these variables affect orbits. In addition, the simulation allows students to explore the effects of gravity. By switching off gravity, students can see how this force directly affects orbital paths. Students are not restricted to investigating just sun/planet relationships. In addition, users can elect to study planet/moon and planet/satellite relationships.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
By using this simulation, students can visualize how changes in size and distance between two objects directly affects gravity and orbital paths. The effect of changes to these variables is immediately seen in the simulation which helps to reinforce the cause and effect relationship. Once students are comfortable with the simulation, teachers could create several specific scenarios and require students to predict how the model would react in each situation.

Resource Quality

  • Alignment to the Dimensions of the NGSS: Gravity and Orbits provides a grade-appropriate, middle school experience while supporting 3-dimensional learning. The simulation provides opportunities to develop both the Disciplinary Core Idea and Crosscutting Concept Dimensions. It is most weakly aligned to NGSS in the area of Practice since students are using, not designing, their own model of gravity.

  • Instructional Supports: Gravity and Orbits uses scientifically accurate and grade‐appropriate scientific information to support students in their investigation of gravity. The simulation is engaging and provides students with relevant phenomena to make sense of the Disciplinary Core Idea. Unfortunately, there is limited opportunity within the simulation for students to discuss and share their understanding of the concepts since the worksheets included in the documentation do not lend themselves to in depth discussion. Teachers may want to supplement the activity with writing prompts for students to complete in their journals. The activity does not provide any suggestions on differentiation.

  • Monitoring Student Progress: The simulation does not include embedded formative assessments or aligned rubrics; however, several worksheets and answer keys can be found in the downloadable manual. In addition, pre and post lab worksheets can be downloaded at: The scripted version of the activity does address possible student misconceptions.

  • Quality of Technological Interactivity: This interactive simulation is highly engaging since it encourages users to be active participants and learners. Middle school students, with teacher support, will find success in understanding the presented concepts.