and motions must be in a system, qualitative described in an arbitrarily comparisons of forces, mass Science Probe: chosen reference frame and and changes in motion PS-20 Space “Outer arbitrarily chosen units of (Newton’s Second Law), Push” size. In order to share frame of reference, and information with other specification of units.] people, these choices must [Assessment Boundary: Science Probe: also be shared. Assessment is limited to PS-21 in the “Riding (MS-PS2-2) forces and changes in motion Parade” PS2.B: of Interactions in one-dimension in an (7th Grade) inertial reference frame, and Science Probe: Electric and magnetic to change in one variable at PS-23 in a “Apple (electromagnetic) forces can a time. Assessment does not Plane” be attractive or repulsive, include the use of and their sizes depend trigonometry.] Science Probe: on the magnitudes of the PS-24 on a MS-PS2-3. Ask questions “Ball charges, currents, or about data to determine the String” magnetic strengths involved factors that affect the and on the distances strength of electric and Science Probe: between the interacting magnetic forces. PS-25 Things “Why objects. (MS-PS2-3) [Clarification Statement: Fall” Gravitational forces are Examples of devices that use always attractive. There is electric and magnetic forces Science Probe: a gravitational force could include PS-28 “Finger between any two masses, electromagnets, electric Strength Contest” but it is very small except motors, or generators. when one or both of the Examples of data could Science Probe: objects have mass—e.g., include the effect of the PS-29 and “Equal Earth and the sun. number of turns of wire on Opposite” (MS-PS2-4) the strength of an Forces that act at a electromagnet, or the effect Science Probe: distance (electric and of increasing the number or PS-30 in a “Riding magnetic) can be explained strength of magnets on the Car” by fields that extend speed of an electric motor.] through space and can be [Assessment Boundary: mapped by their effect Assessment about questions on a test object (a ball, a that require quantitative charged object, or a
and motions must be described in an arbitrarily chosen reference frame and arbitrarily chosen units of size. In order to share information with other people, these choices must also be shared. (MS-PS2-2) PS2.B: of Interactions (7th Grade) Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distances between the interacting objects. (MS-PS2-3) 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 mass—e.g., Earth and the sun. (MS-PS2-4) Forces that act at a distance (electric and magnetic) can be explained by fields that extend through space and can be mapped by their effect on a test object (a ball, a charged object, or a in a system, qualitative comparisons of forces, mass and changes in motion (Newton’s Second Law), frame of reference, and specification of units.] [Assessment Boundary: Assessment is limited to forces and changes in motion in one-dimension in an inertial reference frame, and to change in one variable at a time. Assessment does not include the use of trigonometry.] MS-PS2-3. Ask questions about data to determine the factors that affect the strength of electric and magnetic forces. [Clarification Statement: Examples of devices that use electric and magnetic forces could include electromagnets, electric motors, or generators. Examples of data could include the effect of the number of turns of wire on the strength of an electromagnet, or the effect of increasing the number or strength of magnets on the speed of an electric motor.] [Assessment Boundary: Assessment about questions that require quantitative Science Probe: PS-20 “Outer Space Push” Science Probe: PS-21 “Riding in the Parade” Science Probe: PS-23 “Apple in a Plane” Science Probe: PS-24 “Ball on a String” Science Probe: PS-25 “Why Things Fall” Science Probe: PS-28 “Finger Strength Contest” Science Probe: PS-29 “Equal and Opposite” Science Probe: PS-30 “Riding in a Car”