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In this Universe Sandbox activity, students have to solve the issue of creating a working orbit between an asteroid and the earth.

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PlayMaker School


Universe Sandbox is a powerful and realistic interactive space and gravity simulator. Players can witness scale space simulations of our solar system and galaxy, but they can also see what happens when they manipulate the properties of planets and stars (e.g. mass) or add new bodies in space. The value of Universe Sandbox is its openness, overall accuracy, and impressive visual graphics as it invites players to explore, tinker, and discover their universe in an immersive experience.

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Experience breakdown

Lesson Plan Overview

In this Universe Sandbox activity, students are challenged to save the Earth from an incoming asteroid by using their knowledge of gravitational pull and developing an understanding of velocity. They will discover that objects interacting through gravity either orbit, slingshot, or collide.

This simulation exposes students to the relationship of gravity and velocity of objects in space. Students experience conditions for collision, orbit, and slingshot. Some students may see that several velocities result in stable orbits. Some may even observe that what appears to be a stable orbit will become unstable over long periods of time.

NOTE: At this point, students should be familiar enough with the mechanics and interface of Universe Sandbox from the previous sessions to play, manipulate, and simulate. However, it may be likely that some students will struggle with the controls. We will attempt to document some of the issues that we came across when we facilitated this activity.

2nd NOTE: The scenario file used in this lesson plan we created is available for download on the left-hand side under "Case Studies".

Learning Objectives

  • Students understand that more massive objects change velocity less quickly for a given force.
  • Students realize that the outcome of an interaction of two objects in space is either a collision, orbit, or slingshot, depending on the speed and trajectory.
  • Students change variables, observe outcomes, and refine variables to achieve desired outcomes.

materials & Prep

  • Facilitator computer with a projector with Universe Sandbox and 2nd Scenario file preloaded.
  • Computers or laptops for students, each with Universe Sandbox and the 2nd Scenario file preloaded (we recommend one machine for every three students).
  • The 2nd Scenario has two bodies: the Earth and an asteroid (we chose the body of Ceres for this simulation although any asteroid can work). The trajectory of the asteroid has been set so that it will crash into the Earth when the play button is pressed (video below). We've also included footage of the asteroid escaping from the Earth and a successful orbit around the Earth.

Lesson Steps

STEP 1: Students are shown a simulation in Universe Sandbox in which an asteroid collides with the Earth. They are then shown the use of the hand tool to manipulate the velocity vector of an object, and the time tool for defining the simulation time scale.

Screen Shot 2014-03-14 at 4.56.27 PM.png

Save the Earth

STEP 2: Before playing the simulation, have students predict what will happen. If students aren't making any predictions, they can be prompted to consider:

  • What are the masses of the objects?
  • Does either object have a velocity?
  • Will both objects move? Or just one or the other?

NOTE: Although the second video is entitled STEP 3, it is part of STEP 2. Closed captioning is provided for the videos below because of low sound volume.

An educator helping his students explore the difference between the dimensions of Earth and the asteroid in the simulation.

A student making a prediction about what will happen in the simulation.

STEP 3: Run the simulation (the simulation will show that both objects are moving. The one with the larger mass is changing its velocity more slowly, and the initial velocity of the asteroid is directed toward the Earth and a collision is inevitable) and discuss. The result will be a collision (Outcome 1 in the video from Step 1).

STEP 4: Have students observe the simulation after they have made their predictions. Ask them if what they thought would happen held true. If not, why? Their observations should be written down on the board for the next step.

Closed captioning is available for the video below because of low sound volume.

Students making observations and reacting to the result of the simulation.

STEP 5: In small groups, students are challenged to save the Earth from the asteroid and they are also given the additional restraint that the asteroid must orbit the Earth. Students may change variables associated with that of the asteroid (e.g., mass, velocity, and trajectory) but not of the Earth.


The hand tool is highlighted in this image. Student groups can use this to change the trajectory of the asteroid.

STEP 6: Monitor student progress, giving them five to ten minutes to attempt to complete the challenge.

Some groups may have trouble figuring out a solution, while other groups may manage to do it right away. If this happens, have them save their solution and attempt another solution by making the orbital pattern even smaller.

NOTE: For an additional scenario, ask them to try to create a gravitational slingshot where the asteroid will orbit the Earth and then shoot off away from it (Outcome 2 in the video from Step 1).

A group explaining their challenge, and their first attempt at a solution.

STEP 7:Guide students to understand that velocities at less than a given value result in a collision, velocities at a given value result in an orbit, and velocities above a given value result in a slingshot. Then, have them articulate whether their solution was successful or not. If possible, have them show their solutions on the projector as well.

Closed captioning is provided for the video below because of low sound volume.

A group presenting their successful solution to the class.


Common Core - English Language Arts

Science & Technical Subjects
CCSS.ELA-Literacy.RST.6-8.3 Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks.
CCSS.ELA-Literacy.RST.6-8.7 Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table)

ISTE Standards

1. Creativity and Innovation
Students demonstrate creative thinking, construct knowledge, and develop innovative products and processes using technology.
Apply existing knowledge to generate new ideas, products, or processes
Create original works as a means of personal or group expression
Use models and simulations to explore complex systems and issues
Students use digital media and environments to communicate and work collaboratively, including at a distance, to support individual learning and contribute to the learning of others.
Interact, collaborate, and publish with peers, experts, or others employing a variety of digital environments and media
4. critical thinking, problem solving, & Decision making
Students use critical thinking skills to plan and conduct research, manage projects, solve problems, and make informed decisions using appropriate digital tools and resources.
Identify and define authentic problems and significant questions for investigation
Plan and manage activities to develop a solution or complete a project
Collect and analyze data to identify solutions and/or make informed decisions
Use multiple processes and diverse perspectives to explore alternative solutions
MS-ESS1-2. Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system.

MS-PS2-2. Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object

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.

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