Exploring Gravity

Sarah Borenstein and Trish Loeblein
Type Category
Assessment Materials Instructional Materials
Simulation , Student Guide , Assessment Item , Lesson/Lesson Plan
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 lesson plan and student worksheet have students use an online simulation to explore the relationship between gravitational pull, masses, and distance.  An optional assessment has students write one or two claim-evidence-reasoning paragraphs about whether gravity is a force and about what factors affect the strength of gravity.

Intended Audience

Educator and learner
Educational Level
  • Middle School
  • Grade 8
  • Grade 7
  • Grade 6
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-PS2-4 Construct and present arguments using evidence to support the claim that gravitational interactions are attractive and depend on the masses of interacting objects.

Clarification Statement: Examples of evidence for arguments could include data generated from simulations or digital tools; and charts displaying mass, strength of interaction, distance from the Sun, and orbital periods of objects within the solar system.

Assessment Boundary: Assessment does not include Newton’s Law of Gravitation or Kepler’s Laws.

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

Comments about Including the Performance Expectation
The second of the two optional claim-evidence-reasoning paragraphs assesses this performance indicator. Students will be better able to meet this PE if the teacher holds off on this task until students have completed other lessons involving gravity, especially lessons that involve real objects (e.g. different planets, objects of different masses on Earth) and real data.

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
This is the purpose of the second constructed response question. The variables are strength of gravitational force, mass, and distance. As written, the lesson has students gather qualitative data only; a teacher could encourage students to gather quantitative data from this simulation as well, and could have students use other models, real-word data, etc. to allow students to incorporate quantitative data, and to strengthen their evidence and reasoning about the relationship between gravitational pull, mass, and distance.

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
Because the lesson as written focuses on qualitative data and relationships, students might miss the fact that the forces between the two spheres are incredibly tiny, and just focus on whether the numbers are changing to get bigger or smaller. A teacher will need to point out, or have students determine, what those numbers are “really saying”. Asking or helping students to convert to scientific notation, or counting place values after the decimal, may be ways to do this. It may also be helpful to point out that there’s “nothing special” about the spheres - i.e. that gravity will exist between ANY two objects. (Note: one of the the Analysis questions on page 2 tries to get at the idea of large mass with a question about why bigger planets have more moons. But the number of moons depends on many things besides the mass of the planet.)

Crosscutting Concepts

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

Comments about Including the Crosscutting Concept
The purpose of the lesson is for students to discover that there is a proportional relationship that can describe the strength (magnitude) of gravity between two objects.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This lesson incorporates a disciplinary core idea, practice, and cross-cutting concept. With supplementation from other lessons, its assessment can be used to address the whole of the Performance Indicator.

  • Instructional Supports: This lesson does address 3-dimensional learning. While the “stripped-down model” simulation makes it easy to see what the variables are and how they affect each other, this simulation will not feel real-world to students, due to the unmeasurably tiny forces involved and the setup of two people moving spheres on sticks. The lesson does activate prior knowledge via a warmup and a probe, and revisits it at the close of the lesson. Students have opportunities to explain ideas in written form, and orally in pairs, small groups, and with the whole class. Ideas for differentiation are not included. Overall the lesson is scientifically accurate, but may not feel super relevant to students - it is best used in conjunction with a lesson or lessons involving “real” familiar things, such as planets or falling objects.

  • Monitoring Student Progress: The lesson incorporates probes, quick formative assessments, and optional summative assessments. All of these address ideas from the DCI, Practice, and CCC (Gravity as a force, the proportional relationship between gravity, mass and distance). Scoring guides are not provided. Any standard Claim-Evidence-Reasoning scoring guide would suffice. The summative assessments will be of higher quality, and more benefit to the students, if tackled after some other lessons about gravitational force, so students will have more to draw on, including “real-life” examples.

  • Quality of Technological Interactivity: The Gravity Force Lab simulation is stable, user-friendly, and intuitive to operate even without any instructions. It runs in HTML5, so should not present problems for tablet users.