Communicating Math- Bungee Jump

Today we did an experiment in class where each group had different action figures or objects.  We were going to attach our object to rubber bands and create a bungee cord out of them.  Our group had a hippo toy which we were to use.  For this experiment we were given our object along with a meter stick and ten rubber bands to start.  With these ten rubber bands we were allowed to test out the lengths we believed the rubber bands would stretch when attached to our hippo.  Our data can be seen below:

As you can see we tried 1, 2, 3, 4, 5, and then 7 rubber bands.  Once we did the first five trials, we took the average distance between each trial and noticed the average was 22.625 cm.  Since we originally measured the height of the drop to be 199 in which we converted to 505.46 cm.  We then took 505.46 cm divided by 22.625 cm and found that we would need a little over 22 rubber bands.  Then to make sure our prediction was accurate we knew three times seven was 21 rubber bands so we decided to test seven rubber bands where we found the distance of our object to drop 165.5 cm.  This number was very close to 158.375 cm if we would have multiplied 7 rubber bands by the average distance of each rubber band which, was 22.625.  This indicated to us that no matter how many rubber bands we added to our hippo, each rubber band would stretch approximately the same distance.  Therefore, we multiplied 165.5 cm by  three to find that 21 rubber bands would allow the object to drop 469.5 cm.  The object of this experiment was to get the object as close to the ground as we could without hitting the ground.  Since we had found the distance each rubber band would stretch was constant, and our average per rubber band was 22.625 cm we knew we could add one more rubber band to the 21 rubber bands giving us 22 rubber bands and our object would reach 491.5 cm.  This number(491.5) was roughly 14 cm from the ground.  We knew if we were to add an additional rubber band the object would hit the ground.  We then went to test our object by dropping it and seeing how far from the ground it was.  We were told that our object was roughly 17 cm from the ground when it was dropped with the bungee.  Therefore our prediction was very close to the actual result.  I believe our method worked because we tested several different instances and came up with the same result that on average a rubber band would stretch 22.625cm.  Since we had found a constant we were then able to find an equation to help us find the total number of rubber bands. When we divided the total number of centimeters the jump was (505.46 cm) by the average distance each rubber band stretched (22.625 cm) we found an answer of 22.34 rubber bands would be needed in order for it to reach the ground.  Since the goal was to get as close to the ground as possible without actually touching the ground, we knew that 22 rubber bands was the closest we could get to the ground, when only using whole rubber bands.

Overall, I found this experiment to be helpful in demonstrating a different method of teaching mathematics.  I find that many elementary students are not interested in math and therefore teachers are left trying to find ways to capture students attention in order to get them interested.  I believe students would find this a nice way to learn about estimating as well as creating a equation in order to find the number of rubber bands needed.  By only giving us 10 rubber bands to test ideas with, he made it so that we could not find the result by tying 22 rubber bands together.  He made us dig deeper into our knowledge and use many different math techniques, such as multiplication, division, converting measurements, creating and testing hypotheses.  I will use this method of teaching in my future classroom to get my students up and engaged in their learning.  My favorite way of teaching is to have students explore and find results on their own by personal experience rather than providing step by step instructions for them to follow.  I believe when students create or come up with a strategy on their own they are more likely to remember the strategy in the future.