Rubber Band Lab

In this week's lab, we figured out if the force it takes to stretch a rubber band depends on the amount by which you stretch it. To solve this, we stretched a rubber band to different lengths of .01cm, .02 cm, .03 cm, .04 cm, and .05 cm with the electronic force probe. With one rubber band loop, we measured the following:

.01 m = .4 N

.02 m = 1 N

.03 m = 1.9 N

.04 m = 2.7 N

.05 m  = 3.2 N

We repeated the process with a double rubber band loop and got the following data:

.01 m = 1.6 N

.02 m = 2.2 N

.03 m = 5.5 N

.04 m = 5.6 N

.05 m  = 6 N

We notice that when we stretched the band farther, the force increased. Then, we graphed our data using a best fit line. We were given Fs as the force needed to stretch the band, K as the elastic constant, and X as the distance pulled. We discovered the equation Fs=KX, also known as Hooke's Law. Our graph is shown below:

We measured our energy, area, in the shape of a triangle. Area was represented by Us, the elastic potential energy. Using the standard equation of the triangle, our equation became Us = 1/2 ( base x height). With X as the base, Fs as the height, and using K as the constant, our equation turned into Us = 1/2 (K) (Xsquared). We discovered that distance and force are directly proportional, when one increases so does the other. Here is a picture of our white board:

Real World Connection:

An example of the effects of force and distance is a slingshot. The more force used to pull back, the greater distance it will reach. Therefore, the g reater distance you would like to reach, the more force needed as well. This use of force and distance is a great example of elastic potential energy. Below is an image of a slingshot you could use: