Science.5.7.A
The student is expected to investigate and explain how equal and unequal forces acting on an object cause patterns of motion and transfer of energy; and
Knowledge and Skills Statement
Force, motion, and energy. The student knows the nature of forces and the patterns of their interactions.
Further Explanation
The further explanation is designed to be a resource for educators that helps them better understand the topic their students are learning. Further explanations may be written at a more complex level than would be expected for students at the grade level.
This standard provides students with common experiences and vocabulary to introduce Newton's Laws and the transfer of energy which causes motion. This standard also lays the foundation for net force diagrams in middle school. In grade 2, students design descriptive investigations to explore the differences in motion caused by different amounts of force. In grade 3, students relate the speed of an object to its mechanical energy. In grade 4, students investigate the transfer of energy by objects in motion. In grade 5, students synthesize their previous learning by exploring how the consistency of force applied to an object impacts the transfer of energy to the object and the resulting behavior of the object. In grade 6, students learn about specific forces and use the terms balanced and unbalanced to describe the sum of the forces acting on an object. In grade 7, students will use Newton's First Law of Motion to determine the effects of balanced and unbalanced forces on an object's motion.
In addition to investigating the effects of equal (consistent) and unequal (inconsistent) amounts of force, students might investigate multiple forces acting on the same object simultaneously.
It is helpful to understand the following patterns of motion that students might explore:
Motion of the object | Number of forces applied each time | Directions of multiple applied forces | Strength of the force(s) each time |
The object moves in the direction of the force the same distance each time | Single
| N/A | Equal
|
The object moves in the direction of the force at a different distance each time | Single
| N/A | Unequal
|
No change in motion | Multiple | Opposite directions | Equal |
The combined force is smaller, and the object moves in the direction of the stronger force at different distances each time | Multiple | Opposite directions | Unequal
|
Forces combine, and the object moves in the direction of the force the same distance each time | Multiple | Same direction | Equal
|
Forces combine, and the object moves in the direction of the force at different distances each time | Multiple | Same direction | Unequal |
Supporting Information
Research
Bobrowsky, M. Science 101 Q: What’s Wrong With “For Every Action, There is an Equal and Opposite Reaction”? Science and Children, (March 2019): 69–73.
Summary: This article explains how forces act on each other. It asks readers to clap their hands together to see that they feel the same amount of force from each hand and that the forces are equal in strength and opposite in direction. Similarly, magnets can either attract or repel each other, but the forces from each magnet are the same and occur simultaneously. Many students are surprised to learn that when gravity acts on an object, like an apple falling to the ground, the apple also exerts a small gravitational tug on the Earth. Students should know that forces come in pairs. Students can observe a set of blocks stacked on top of each other and try to identify all of the pairs of forces.