Ballistics is the study of the behavior, motion, and effects of projectiles, which includes bullets, rockets, and other objects that are propelled through space. Ballistics covers the science behind how projectiles are launched, the path they take, and the impact they have on their targets. Ballistics is typically divided into three main areas:

1. Internal Ballistics: This focuses on what happens inside a firearm or launcher, from the moment the trigger is pulled to when the projectile exits the barrel. It includes studying the forces generated by gunpowder, how gases expand, and the factors affecting the projectile's initial speed.
2. External Ballistics: This examines the projectile's path once it leaves the barrel, affected by factors like gravity, air resistance, wind, and even the Earth's rotation. External ballistics deals with the flight dynamics, such as trajectory, velocity, and stability in the air.
3. Terminal Ballistics: This area studies the interaction of the projectile with its target. It includes analyzing impact, penetration, and any damage or energy transfer upon hitting the target, which is especially important in forensic science and military applications.

Some also consider transitional ballistics a fourth area, focusing on the transition of the projectile from the barrel to the open air, but it’s often included under internal or external ballistics.