Rubber Band Stretching

The overview of our setup.	The BB Gun resting on a rifle holder fastened to the table.
BB Gun positioned to fire at rubber band with cardboard BB catcher behind it.	Lamp positioned on our rubber band setup.
The light shining on our rubber band setup with a dark backdrop.	The camera connected to the MotionScope 800 which is connected to the video camera for final recording.

May 2nd, 2007

We gathered most of our equipment and set up for testing. We cut rubber 

bands and secured the gun stand to the table. However, we realized that we

needed some rubber bands that were thicker in order to withstand the force 

of the BB and not rip. 

May 3rd, 2007

We continued gathering materials and setting up our project, including positioning

the MotionScope 8000S and the rifle. We learned how to use the MotionScope 8000S 

and the rifle, and tested the rubber bands we made the day before. As we had 

predicted, the rubber bands were not strong enough to withstand the force of the BB,

which simply made a hole in the rubber band. We were still searching for a proper 

rubber band.  

May 4th, 2007

We finally completed our first trial, and recorded the event. However, we did not have

the correct video camera in order to transfer our clips from the MotionScope 8000S to 

video. 

May 9th, 2007

We recorded the first few trials, starting with a rubber band of length 10.3 cm. We 

are getting used to aiming the rifle at the center of the rubber band. 

May 10th, 2007

We recorded more trials, increasing the increment by about 1 cm, until our rubber band 

was about 16.4 cm. However, we find that it is difficult to aim the BB gun precisely at 

the center of the rubber band. Some shots slip off the side or are too high/low. Some 

BBs went through the rubber band completely instead of stretching it horizontally. 

May 11th, 2007

We finished recording our all our trials, ending with a vertical stretch of 20.2 cm. We 

then took pictures for our website. We were really happy to finish because one of the 

clamps on the ring stand broke during the last trial.

May 16th, 2007 

We used Tracker software to analyze half of our videos. After measuring the maximum 

horizontal stretch and plotting horizontal stretch vs. vertical stretch, we found no clear 

relationship so far.

May 17th, 2007 

We finished analyzing the rest of our video clips and our data. We still found no correlation

between vertical stretch and horizontal stretch.

May 18th, 2007

We tried to reach a conclusion for our data. We decided that other variables caused our data 

to be inconclusive. These variables included the position of the BB when it hit the rubber band, 

since a centered hit was necessary for precise results. Changing the rubber band between trials 

also created variation. Horizontal stretch also seems to depend on the number of times we used 

the rubber band, since continuous use can stretch out the rubber band.