Some things go fast like a car driving down the highway or a jet flying across the country. The earth goes really fast around the sun. For example, a train traveling to from Boston to San Francisco travels at so many kilometers in an hour. If it is not an express train, it stops at several cities along the way. A graph of this motion tells you how fast and in what direction the train is moving as it crosses the country.

Think about other objects that show you a change in velocity. Be prepared to share your list with the class.

A graph of distance versus time gives certain information visually about the motion of an object. It shows if an object is speeding up or slowing down. It also tells you what direction an object is moving. The main emphasis in this activity is to relate distance versus time graphs to actual movements by using a sonar ranger.