MS-ESS1-2 | Gravity and Orbits
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 could include physical models (such as a model of the solar system scaled using various measures or computer visualizations of elliptical orbits) or conceptual models (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.
Performance Level Descriptions
PLDs communicate the knowledge and skills expected of students to demonstrate proficiency in each Learning Standard. NYS assessments classify student performance into one of five levels.
Resources
Examples and discussion of resources for the learning, teaching, and assessment of MS-ESS1-2.

Assessment
What assessment of MS-ESS1-2 might look like on a NY state exam.
NGSS Dimensions
Performance expectation MS-ESS1-2 was developed using the following elements from the NRC document A Framework for K-12 Science Education:
- Developing and Using Models
- Develop and use a model to describe phenomena.
- ESS1.A: The Universe and Its Stars
- Earth and its solar system are part of the Milky Way galaxy, which is one of many galaxies in the universe.
- ESS1.B: Earth and the Solar System
- (NYSED) The solar system consists of the Sun and a collection of objects, including planets, their moons, comets, and asteroids that are held in orbit around the Sun by its gravitational pull on them.
- The solar system appears to have formed from a disk of dust and gas, drawn together by gravity.
- Systems and System Models
- Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy and matter flows within systems.
Connections to Other Standards
MS-ESS1-2 connections to ELA, math, and other science standards as outlined by the NYS Education Department: