The relative speed of two objects can be determined in two ways: (1) If two objects travel for the same amount of time, the object that has traveled the greatest distance is the fastest. (2) If two objects travel the same distance, the object that takes the least time to travel the distance is the fastest.
Force and Motion
In prior grades students learned that forces work not only to push and pull objects, but also to affect objects when they are dropped or thrown. In grades 4-5 students learn how to use basic tools to measure the fundamental quantities of force, time, and distance. Force can be measured with a spring scale. Distance and time can be measured by a variety of methods, and the results can be used to compare the motion of two objects. Focusing on accuracy of measurement, recording of data and logical conclusions from the data provide the foundation for future years when students will undertake more complex investigations.