Science Assessment ~ Ideas ~ Motion energy (kinetic energy) is associated with the speed and the mass of an object.

Key Idea: When two objects change relative position as a result of a contact force or a gravitational, magnetic, or electric force, the potential and kinetic energies of the system change.

Sub-Ideas
Items & Student Performance
Misconceptions
NGSS

Students should know that:

A force field (gravitational, magnetic, and electric) can change the potential and kinetic energies that a system of two object has so that some of the energy of the system is converted from potential energy to the kinetic energy of one or both of the objects as the objects move to new locations in the force field.
If the force acting on an object is attractive (magnetic, electric, or gravitational), the potential energy of the system decreases and the kinetic energy of one or both of the objects increases as the objects move closer together [in the absence of other forces].
If the force acting on an object is repulsive (magnetic or electric but not gravitational), the potential energy of the system decreases and the kinetic energy of one or both of the objects increases as the objects move farther apart [in the absence of other forces].
Energy is being transferred by forces as long as 1) one object exerts a force on another object and 2) the position and/or shape (or orientation in the case of magnetic forces) of the object being pushed or pulled is changing. The transfer of energy stops when one object no longer exerts a force on the other object or when the change in position and/or shape stops. There is no transfer of energy by forces between objects that are at rest.
When two equal forces act in the same direction but over different distances, the force that acts over the longer distance transfers more energy than the force that acts over the shorter distance.

Boundaries:

Assessment items are limited to systems containing two objects that are moving or that can be moved.
For magnetic interactions, assessment items are limited to systems containing macroscopic magnets and macroscopic magnetized objects, and not individual particles in a magnetic field.
Items will not ask students to calculate how much energy is transferred mechanically in a particular situation.
Assessment items will not use the word “work” or “fields.”

Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID Number	Knowledge Being Assessed	Grades 4–5	Grades 6–8	Grades 9–12
RG160002	As a meteoroid approaches the earth, the gravitational force field of earth causes some of the potential energy of the earth-meteoroid system to be converted to the kinetic energy of the meteoroid.	N/A	39%	47%
RG101002	Energy is transferred when a magnet exerts a force on an iron object and the position of the object changes.	N/A	30%	28%
RG076003	Energy can be transferred by magnetic forces on the moon because magnetic forces act at a distance even when there is no air. Energy can be transferred by forces that act at a distance as long as there is a change in position of either the magnet or the iron rod.	N/A	27%	28%
NG052003	Energy is transferred mechanically if one object pushes or pulls on another object and the objects move.	N/A	24%	23%
RG121002	Energy is transferred between to magnets only when the distance between the magnets changes.	22%	21%	21%
RG165002	For energy to be transferred between magnets, the distance between the magnets must change.	N/A	18%	21%

Frequency of selecting a misconception
Misconception ID Number	Student Misconception	Grades 4–5	Grades 6–8	Grades 9–12
NGM058	Energy is transferred mechanically whenever one object pushes or pulls on another, even if the objects do not move (AAAS Project 2061, n.d.).	N/A	39%	40%
RGM082	Magnets transfer energy all the time (AAAS Project 2061, n.d.). Student say "whenever a magnet is close to a iron block it transfers energy" (zzzzfc/811/17) or "The magnetic field transfers energy to the metal at all times..."(zzzzfc/773/17).	43%	39%	37%
RGM098	Magnets require a medium to transfer energy.	N/A	32%	30%
NGM010	Energy can be created (Kruger, 1990; Lovrude, 2004; Papadouris et al., 2008).	N/A	28%	25%
RGM100	Magnets transfer forces, not energy.	28%	26%	27%
NGM005	Energy can be transformed into a force (AAAS Project 2061, n.d.).	N/A	20%	18%
NGM034	When one object pushes or pulls on another object, a force, not energy, is transferred (AAAS Project 2061, n.d.).	N/A	18%	19%
RGM046	Only contact forces can transfer energy	7%	11%	11%
NGM059	Energy cannot be transferred from one object to another (AAAS Project 2061, n.d.).	N/A	8%	7%

Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.

NGSS Statements
Code	Statement
PS3.C MS	When two objects interact, each one exerts a force on the other that can cause energy to be transferred to or from the object.
PS3.C HS	When two objects interacting through a field change relative position, the energy stored in the field is changed.
PS2.B MS	Forces that act at a distance (electric, magnetic, and gravitational) can be explained by fields that extend through space and can be mapped by their effect on a test object (a charged object, or a ball, respectively).