# The Standards

### Earth's Place in the Universe

#### Students who demonstrate understanding can:

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

Clarification Statement and Assessment Boundary

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.

##### Science and Engineering Practices

Developing and Using Models

Modeling in 6–8 builds on K–5 experiences and progresses to developing, using, and revising models to describe, test, and predict more abstract phenomena and design systems.

##### Disciplinary Core Ideas

ESS1.AThe Universe and Its Stars

ESS1.BEarth and the Solar System

##### Crosscutting Concepts

Systems and System Models

###### Connections to Nature of Science

Scientific Knowledge Assumes an Order and Consistency in Natural Systems

### Common Core State Standards Connections

Mathematics
• 6.EE.B.6 - Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set. (MS-ESS1-2)
• 6.RP.A.1 - Understand the concept of a ratio and use ratio language to describe a ratio relationship between two quantities. (MS-ESS1-2)
• 7.EE.B.4 - Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities. (MS-ESS1-2)
• 7.RP.A.2 - Recognize and represent proportional relationships between quantities. (MS-ESS1-2)
• MP.4 - Model with mathematics. (MS-ESS1-2)

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