the Physics Education Technology Project
This is a student guide developed specifically for use with the PhET simulation My Solar System. Intended for Grades 8-9, it provides explicit directions for set-up and promotes critical reasoning about factors that influence orbital motion and gravity. Students will make predictions and tackle conceptual questions before attempting any mathematics.
The parent resource (My Solar System simulation) allows users to set initial positions, velocities, and masses of 2, 3, or 4 bodies, and then see them orbit each other. See Related Materials for a link to the simulation and to a 10-minute video on gravity by the same author.
Please note that this resource requires
Java Applet Plug-in.
Editor's Note:Why We Like It: Veteran high school teacher Dan Burns, who authored this activity, has created a solid starting point for beginners to understand gravity and its effects. Kids will explore gravitational acceleration and Newton's Universal Law of Gravitation in one activity.....while playing with a cool simulation. The activity meets a plethora of NGSS standards as well.
acceleration, gravitation, gravitational acceleration, lunar orbits, motion, orbit simulation, planet simulation, planetary system, planets, planets and moons, satellite, satellite simulation, solar system simulation, velocity
Metadata instance created
January 27, 2014
by Caroline Hall
January 27, 2014
by Caroline Hall
Last Update when Cataloged:
January 12, 2012
AAAS Benchmark Alignments (2008 Version)
1. The Nature of Science
1A. The Scientific Worldview
9-12: 1A/H1. Science is based on the assumption that the universe is a vast single system in which the basic rules are everywhere the same and that the things and events in the universe occur in consistent patterns that are comprehensible through careful, systematic study.
4. The Physical Setting
4A. The Universe
9-12: 4A/H4. Mathematical models and computer simulations are used in studying evidence from many sources in order to form a scientific account of the universe.
6-8: 4F/M3a. An unbalanced force acting on an object changes its speed or direction of motion, or both.
6-8: 4F/M3b. If a force acts towards a single center, the object's path may curve into an orbit around the center.
9-12: 4F/H2. All motion is relative to whatever frame of reference is chosen, for there is no motionless frame from which to judge all motion.
9-12: 4F/H8. Any object maintains a constant speed and direction of motion unless an unbalanced outside force acts on it.
4G. Forces of Nature
6-8: 4G/M2. The sun's gravitational pull holds the earth and other planets in their orbits, just as the planets' gravitational pull keeps their moons in orbit around them.
9-12: 4G/H1. Gravitational force is an attraction between masses. The strength of the force is proportional to the masses and weakens rapidly with increasing distance between them.
11. Common Themes
6-8: 11B/M4. Simulations are often useful in modeling events and processes.
9-12: 11B/H1a. A mathematical model uses rules and relationships to describe and predict objects and events in the real world.
9-12: 11B/H2. Computers have greatly improved the power and use of mathematical models by performing computations that are very long, very complicated, or repetitive. Therefore, computers can reveal the consequences of applying complex rules or of changing the rules. The graphic capabilities of computers make them useful in the design and simulated testing of devices and structures and in the simulation of complicated processes.
9-12: 11B/H3. The usefulness of a model can be tested by comparing its predictions to actual observations in the real world. But a close match does not necessarily mean that other models would not work equally well or better.
Next Generation Science Standards
Motion and Stability: Forces and Interactions (MS-PS2)
Students who demonstrate understanding can: (6-8)
Construct and present arguments using evidence to support the claim that gravitational interactions are attractive and depend on the masses of interacting objects. (MS-PS2-4)
Motion and Stability: Forces and Interactions (HS-PS2)
Students who demonstrate understanding can: (9-12)
Use mathematical representations of Newton's Law of Gravitation and Coulomb's Law to describe and predict the gravitational and electrostatic forces between objects. (HS-PS2-4)
Disciplinary Core Ideas (K-12)
Forces and Motion (PS2.A)
The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. (6-8)
Types of Interactions (PS2.B)
Gravitational forces are always attractive. There is a gravitational force between any two masses, but it is very small except when one or both of the objects have large mass—e.g., Earth and the sun. (6-8)
Newton's law of universal gravitation and Coulomb's law provide the mathematical models to describe and predict the effects of gravitational and electrostatic forces between distant objects. (9-12)
Relationship Between Energy and Forces (PS3.C)
When two objects interact, each one exerts a force on the other that can cause energy to be transferred to or from the object. (6-8)
Crosscutting Concepts (K-12)
Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena. (9-12)
Cause and Effect (K-12)
Cause and effect relationships may be used to predict phenomena in natural systems. (6-8)
Scale, Proportion, and Quantity (3-12)
Time, space, and energy phenomena can be observed at various scales using models to study systems that are too large or too small. (6-8)
Systems and System Models (K-12)
Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy and matter flows within systems. (6-8)
Systems may interact with other systems; they may have sub-systems and be a part of larger complex systems. (6-8)
When investigating or describing a system, the boundaries and initial conditions of the system need to be defined. (9-12)
Science and Engineering Practices (K-12)
Developing and Using Models (K-12)
Modeling in 6–8 builds on K–5 and progresses to developing, using and revising models to describe, test, and predict more abstract phenomena and design systems. (6-8)
Develop a model to predict and/or describe phenomena. (6-8)
Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds. (9-12)
Use a model to predict the relationships between systems or between components of a system. (9-12)
Use a model to provide mechanistic accounts of phenomena. (9-12)
This resource is part of a Physics Front Topical Unit.
Topic: Kinematics: The Physics of Motion Unit Title: Planetary Motion
This 40-minute lesson, created by a veteran high school teacher, gives kids explicit guidance in using the PhET simulation My Solar System to explore orbital motion and gravitational attraction. Great concept building activity.
Burns, D. (2012, January 12). PhET Teacher Activities: My Solar System-Gravity Lab. Retrieved July 29, 2014, from Physics Education Technology Project: http://phet.colorado.edu/en/contributions/view/3353
%0 Electronic Source %A Burns, Dan %D January 12, 2012 %T PhET Teacher Activities: My Solar System-Gravity Lab %I Physics Education Technology Project %V 2014 %N 29 July 2014 %8 January 12, 2012 %9 application/ms-word %U http://phet.colorado.edu/en/contributions/view/3353
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This 10-minute video was created by the same author (Dan Burns) and provides a highly visual depiction of the concepts covered in this classroom lesson, plus additional exploration of the topic of gravity