Final answer:
The statement about magnetizing an iron bar by applying a magnetizing force is true because the ferrous molecule electrons within the magnetic domains align with the external magnetic field, resulting in the bar becoming magnetized.
Step-by-step explanation:
The statement that when a magnetizing force is applied to the end of an iron bar, the magnetic field of many of the ferrous molecule electrons will align with each other, resulting in the bar demonstrating magnetic properties, is true. Ferromagnetic materials like iron contain several magnetic domains, which are essentially tiny magnets. These domains have randomly oriented poles in an unmagnetized state. When exposed to an external magnetic field, the domains tend to align with the magnetic field vector.
As the domains align, some grow at the expense of others, leading to an overall magnetization of the material. This is consistent with Essential Knowledge 2.D.3, which states that a magnetic dipole will tend to align with a magnetic field vector, and with Essential Knowledge 2.D.4, which indicates that ferromagnetic materials contain magnetic domains that become aligned magnets in the presence of a magnetic field. This entire process is an example of how forces can interact with objects at the macroscopic level, which can be described by Big Idea 3 and Enduring Understanding 3.C detailing the categorization of forces. The alignment of magnetic domains resulting from an external magnetizing force is one such long-range (action-at-a-distance) force.