Momentum conservation and energy loss in collisions can be introduced intuitively by first considering the situation in which the total momentum is zero. Other cases, such as collision with a stationary object, are easily described by transforming the velocities of the zero momentum result. All two body, one-dimensional collisions can be easily treated this way without the need for solving simultaneous equations. Treatment of the general case leads immediately to conservation of momentum and to Newton’s law of elasticity.