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.

MS-PS2-5: Conduct an investigation and evaluate the experimental design to provide evidence that fields exist between objects exerting forces on each other even though the objects are not in contact.
Clarification Statement: Examples of this phenomenon could include the interactions of magnets, electrically-charged strips of tape, and electrically-charged pith balls. Examples of investigations could include first-hand experiences or simulations.

By the end of grade 8.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. 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 large mass for example, Earth and the sun. Long-range gravitational interactions govern the evolution and maintenance of large-scale systems in space, such as galaxies or the solar system, and determine the patterns of motion within those structures. Forces that act at a distance (gravitational, electric, and magnetic) can be explained by force fields that extend through space and can be mapped by their effect on a test object (a ball, a charged object, or a magnet, respectively).

Evidence Statements

MS-PS2-3

1. Addressing phenomena of the natural world or scientific theories

   1. Students formulate questions that arise from examining given data of objects (which can include particles) interacting through electric and magnetic forces, the answers to which would clarify:

      1. The cause-and-effect relationships that affect magnetic forces due to:

         1. The magnitude of any electric current present in the interaction, or other factors related to the effect of the electric current (e.g., number of turns of wire in a coil).

         2. The distance between the interacting objects.

         3. The relative orientation of the interacting objects.

         4. The magnitude of the magnetic strength of the interacting objects.

      2. The cause-and-effect relationships that affect electric forces due to:

         1. The magnitude and signs of the electric charges on the interacting objects.

         2. The distances between the interacting objects.

         3. Magnetic forces.

      3. Based on scientific principles and given data, students frame hypotheses that:

         1. Can be used to predict the strength of electric and magnetic forces due to cause-and-effect Relationships.

         2. Can be used to distinguish between possible outcomes, based on an understanding of the cause-and-effect relationships driving the system.

         3. Identifying the scientific nature of the question

            1. Students’ questions can be investigated scientifically within the scope of a classroom, outdoor environment, museum, or another public facility.