Department of Mathematics Education
Rate and Distance
Students will measure the time required for battery-powered cars to travel a measured distance, and calculate the speed of the cars.† Based on the comparisons, a winner of the race will be predicted.† An actual race will test the validity of the prediction.
To motivate students, discuss how speed can be measured in a car.† How would you measure your speed if the speedometer were broken?† Next, discuss formulas, rearranging formulas, rounding, and averaging.† Adjust the distances for your races, if necessary.
Place a 1-foot piece of tape on the floor as a starting line.† Measure 15 feet and place another 1-foot piece of tape for a finish line.† Form a team to work with each car.† Each team should measure the time required for its car to go from the starting line to the finish line.† Write this time on a sheet of data paper.† Repeat and record the measurements for a total of five trial runs for each car.† Use an appropriate formula to calculate the speed of the car for each trial run in feet per second (ft/sec).† Round each answer to the nearest hundredth of a foot per second.† Calculate the average speed of the car for the five trial runs to the nearest hundredth of a ft/sec.† When all groups have finished recording results, compare the average speeds and predict which teamís car will win a race.† Measure a distance of 25 feet.† Race the cars over the 25-foot distance.† Record which cars take the first three places.† How do the results of the race compare with the predictions made?