Clarification Statement - S.K.PS.2.1.CS:
Examples of pushes or pulls could include a string attached to an object being pulled, a person pushing an object, a person stopping a rolling ball, and two objects colliding and pushing on each other.

Assessment Boundary - S.K.PS.2.1.AB:
Assessment is limited to different relative strengths or different directions, but not both at the same time. Assessment does not include non-contact pushes or pulls such as those produced by magnets.

Science and Engineering Practices - PK2.SEP3.1:
With guidance, plan and conduct an investigation incollaboration with peers.

Disciplinary Core Ideas - S.K.PS.2.1.DCI:
PS2.A: Forces and Motion •Pushes and pulls can have different strengths and directions. •Pushing or pulling on an object can change the speed or direction of its motion and can start or stop it. PS2.B: Types of Interactions •When objects touch or collide, they push on one another and can change motion. PS3.C: Relationship Between Energy and Forces •(NYSED) A push or a pull may cause stationary objects to move, and a stronger push or pull in the same or opposite direction makes an object in motion speed up or slow down more quickly.

Crosscutting Concepts - CC2.1:
Simple tests can be designed to gather evidence to support or refute student ideas about causes.

Clarification Statement - S.K.PS.2.2.CS:
Examples of problems requiring a solution could include having a marble or other object move a certain distance, follow a particular path, and knock down other objects. Examples of solutions could include tools such as a ramp to increase the speed of the

Assessment Boundary - S.K.PS.2.2.AB:
Assessment does not include friction as a mechanism for change in speed.

Science and Engineering Practices - PK2.SEP4.3:
Analyze data from tests of an object or tool to determine if it works as intended.

Disciplinary Core Ideas - S.K.PS.2.2.DCI:
PS2.A: Forces and Motion •Pushes and pulls can have different strengths and directions. •Pushing or pulling on an object can change the speed or direction of its motion and can start or stop it. ETS1.A: Defining Engineering Problems •A situation that ppeople want to change or create can be approached as a problem to be solved through engineering. Such problems may have many acceptable solutions. (secondary to K-PS2-2)

Crosscutting Concepts - CC2.1:
Simple tests can be designed to gather evidence to support or refute student ideas about causes.