Isaac Newton provided some of the most prominent contributions to classical physics, which generally refers to the field before major developments in the 1900s such as relativity and quantum mechanics. The physicist produced three laws of motion based on objects that are visible with the naked eye. The first rule, often called the law of inertia, describes the observation that an object measured from a inertial frame of reference will maintain speed and direction of motion unless it is acted upon by a non-balanced force like friction. The second law states that speed and direction of a mass can be changed by a force, which is described as an alteration in momentum. If the force is gravity, which is forever linked with Newton thanks to the falling apple legend, then only the speed of the object will be altered. The third law of classical physics provided by the scholar is widely known as the law of equal and opposite reaction. This principle is based on the observation that forces come in polar pairs, like the strength of gravity being paired with the momentum change in falling objects. Newton’s laws provided the framework needed for many significant advancements in classical physics.