Balanced forces, friction and the push test

Scientists test ideas. First they make a prediction: a stronger push will send a toy car farther. Then they run a fair test. They change only one thing, the strength of the push, and keep everything else the same: the car, the floor and the starting line. They measure how far the car goes with a tape and repeat the push three times, because one try can be a little different. To find the average, add the three distances and divide by 3. Last they compare the data with the prediction. If the results match, the data support the prediction. If they do not, the data contradict it, and the scientist thinks again. A stronger push gives the car more energy, so it goes farther before friction stops it.