Speed Tests

This week our second and third graders have been continuing to learn about force in science. In order to learn about how the mass of an object can influence how fast the object moves, we decided to do a bit of a test. Students were placed into groups of three and the groups were given materials to make a ramp (books and whiteboards), a tape measure, a toy car, an iPad (for the stopwatch), masking tape, and play dough. Students conducted this experiment in the gym because there is less friction on the gym floor, which makes for a better experiment. However, before going to the gym, students wrote down the necessary steps to the test they were going to do and assigned each person a job in the experiment.

Once we were in the gym, each group of students built their ramp and placed tape on the gym floor for their "finish line" (20 inches from the end of the ramp). After building the ramp and taking measurements, students tested letting go of their car and timing to see how long it took the car to reach the finish line. After testing the car three times and finding the median time, students then took the play dough and placed it on top of their car in order to add more mass to their car. Then, with the play dough on top of their car, students conducted the same experiment to see how long it took the heavier car to cross the finish line with play dough on top of it. After testing it three times, students once again found the median time and they compared the different times.

Back in the classroom, we found the median speed of the cars without play dough and the median speed of the car with the play dough by dividing the distance (20 inches) by the time (how many seconds it took the car to cross the finish line). Students then compared the speed of the car with the play dough and without the play dough. They noticed that the car had a faster speed without the play dough then the car that had the play dough. So, we realized through this experiment that how much an object weighs (its mass) will have an influence on the speed of that object. Students loved getting to experiment with the different objects throughout this test and they learned a lot!