Look At Me, Ma, I Can Fly Like A Bird! 9.30

Our second science unit focused on disciplinary understanding -- an understanding of the nature of science and scientific inquiry. These photos are from the first of two experiments exploring the scientific method and the control of variables. The following is from the final report (minus images/graphs):

INTRODUCTION AND PREDICTIONS

The purpose of this experiment was to see if there was a relationship between the height of a student and the distance they were able to jump. Our teacher thought that since professional basketball and volleyball players tend to be tall, and they do a lot of jumping, it must be true that taller people can jump farther.

PROCEDURE

We tested our teacher’s prediction by following these steps:

1. We measured students’ heights (to the nearest half centimeter) using two meter sticks taped end-to-end vertically on a classroom wall. Each student recorded the heights of their classmates on a data sheet. (See Table 1 and Photos 1-3.)

2. Students each completed three standing broad jumps, without practice, and each jump was recorded on the data sheet, rounded to the near half centimeter. The best of the three jumps was later graphed, along with the student’s height (see Graph 1).

3. The distance of each jump was measured from a tape line (against which students aligned their toes) to the back heel of the foot closest to the tape line (or the body part which landed closest to the tape line, be it a hand or a buttocks). Note Photos 4-6.

RESULTS AND CONCLUSIONS

The results of this experiment can be found in Graph 1. Students’ heights were graphed along with their best jump.

If our teacher’s prediction were correct, we would expect the graph to slope upward from left to right, indicating that taller students were jumping farther. If shorter students were jumping farther, then we’d expect the opposite. If there were no relationship between a student’s height and the distance they jumped, then we’d expect a scatter of data points without pattern.

As you can see in Graph 1, our results show no clear relationship between a student’s height and the distance jumped. Our teacher’s prediction, sadly, was not proven by this experiment.

DISCUSSION

We discovered that this experiment had many flaws, including:

= The clothing that students wore during the experiment varied widely, from sports’ shorts to long leg jeans. We believe that light and loose-fitting clothing may have provided an advantage.

= What students wore on their feet also varied, from socks to bare foot. Socks, in some cases, proved to be slippery, so students with bare feet may have had an advantage.

= Students varied in their level of general fitness and leg strength, which might have provided an advantage.

= Students varied in their attitude and level of interest and motivation. Interested, motivated and positive students might have had a clear advantage.

= Students varied in the technique, which has nothing to do with height.

= We did not consider a student’s weight, which may significantly affect a student’s performance.

= The kids watching their classmates jump varied in their conduct, from quiet and polite to noisy and distracting, on occasion even rude.

Thus, the experiment was a very good bad experiment. We must, in the future control all of these variables, and be sure that all students in the experiment wear the same clothes, be similarly fit, motivated and practiced. We might also require that all spectators be silent and polite. We invite you to repeat our experiment to see if you get the same results.