Rubber Band Lab

Purpose: The purpose of this lab was to observe the spring/elastic potential energy by measuring the amount of force it takes to stretch a rubber band. Through our data, we discovered the "displacement from equilibrium" or the amount of stretch. Our data helped us answer the Big Question, "How does the force it takes to stretch a rubber band depend on the AMOUNT by which you stretch it?"

How?: To test our big questions, we started with a rubber band at equilibrium. We used the force probe to stretch the rubber band a given distance (1cm, 2cm, 3cm, 4cm, 5cm). After we stretched the rubber band to the given distance and holding it steady for at least 10 seconds, we used the LabQuest to average the measure of force it took to hold the rubber band steady. We recorded our data. 

Graph: To determine the amount of force used in each trial, we used the equation F=kx 
K=spring constant x=displacement from equilibrium

However, F=kx was only one equation we covered. After finding this equation, we had to find the area of each triangle (A=1/2bh). Finding the area of each triangle meant that we were finding the Energy of each trial (spring potential energy). 

To find "Spring potential energy" we went from  A=1/2bh ----> Us=1/2(x)(Fs)

Since Fs=kx--------> Us=1/2(x)(kx)

with 2 "x"s---------> Us=1/2kx^

Real World: Spring potential energy can be seen in many aspects of everyday life. For example, a diving board. Imagine standing on the board--you are at equilibrium. However, after you jump off you are displacing it from equilibrium. The amount of energy can be determined by calculating the amount of force it takes to displace the diving board and the spring constant of the board.