Clarification Statement - S.3.PS.2.1.CS:
Examples could include an unbalanced force on one side of an object can make it start moving; andbalanced forces (including friction) acting on a stationary object from both sides will not produce any motion at all.]

Assessment Boundary - S.3.PS.2.1.AB:
Assessment is limited to one variable at a time: number, size, or direction of forces. Assessment does not include quantitative force size, only qualitative and relative. Assessment is limited to gravity being addressed as a force that pulls objects down

Science and Engineering Practices - 3-5.SEP3.2:
Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence, using fair tests in which variables are controlled and the number of trials considered.

Disciplinary Core Ideas - S.3.PS.2.1.DCI:
PS2.A: Forces and Motion •Each force acts on one particular object and has both strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object. Forces that do not sum to zero can cause changes in the object’s speed or direction of motion. (Boundary: Qualitative and conceptual, but not quantitative addition of forces are used at this level.) PS2.B: Types of Interactions •Objects in contact exert forces on each other.

Crosscutting Concepts - CC2.3:
Cause and effect relationships are routinely identified.

Clarification Statement - S.3.PS.2.2.CS:
Examples of motion with a predictable pattern could include a child swinging in a swing, a ball rolling back and forth in a bowl, and two children on a see-saw.

Assessment Boundary - S.3.PS.2.2.AB:
Assessment does not include technical terms such as period and frequency.

Science and Engineering Practices - 3-5.SEP3.1:
Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon or test a design solution

Disciplinary Core Ideas - S.3.PS.2.2.DCI:
PS2.A: Forces and Motion •The patterns of an object’s motion in various situations can be observed and measured; when that past motion exhibits a regular pattern, future motion can be predicted from it. (Boundary: Technical terms, such as magnitude, velocity, momentum, and vector quantity, are not introduced at this level, but the concept that some quantities need both size and direction to be described is developed.)

Crosscutting Concepts - CC1.4:
Patterns of change can be used to make predictions.

Clarification Statement - S.3.PS.2.3.CS:
Examples of an electric force could include the force on hair from an electrically charged balloon and the electrical forces between a charged rod and pieces of paper; examples of a magnetic force could include the force between two permanent magnets, the

Assessment Boundary - S.3.PS.2.3.AB:
Assessment is limited to forces produced by objects that can be manipulated by students, and electrical interactions are limited to static electricity.

Science and Engineering Practices - 3-5.SEP1.1:
Ask questions that can be investigated based on patterns such as cause and effect relationships.

Disciplinary Core Ideas - S.3.PS.2.3.DCI:
PS2.B: Types of Interactions •Electric and magnetic forces between a pair of objects do not require that the object s be in contact. The sizes of the forces in each situation depend on the properties of the objects and their distances apart and, for forces between two magnets, on their orientation relative to each other.

Crosscutting Concepts - CC2.4:
Cause and effect relationships are routinely identified, tested, and used to explain change.

Clarification Statement - S.3.PS.2.4.CS:
Examples of problems could include constructing a latch to keep a door shut and creating a device to keep two moving objects from touching each other.

Science and Engineering Practices - 3-5.SEP1.2:
Define a simple problem that can be solved through the development of a new or improved object or tool.

Disciplinary Core Ideas - S.3.PS.2.4.DCI:
PS2.B: Types of Interactions •Electric and magnetic forces between a pair of objects do not require that the object s be in contact. The sizes of the forces in each situation depend on the properties of the objects and their distances apart and, for forces between two magnets, on their orientation relative to each other.