You can see that this mostly looks like a linear relationship between the stretch distance and the force just like a spring. The slope of this line would be the spring constant with a value of This means that if I stretch the rubber band a distance of about 20 centimeters that's around the breaking point then there would be 1.
But wait! There is another way to store energy in a spring. Instead of stretching it, I can twist the rubber band up—you know, the way it works on one of those rubber band powered balsa wood airplanes. The nice thing about winding a rubber band up instead of stretching is that it doesn't really take up more room as you store energy in it. Also, it releases energy while unwinding in a much more controlled fashion than it would by stretching.
However, if the spring doesn't stretch then it's pretty hard to measure the spring constant—so I will just do something else. If I measure the torque required to twist the rubber band I can do something very similar to the linearly stretched rubber band.
In this case, I can measure the twisting torque with a force probe placed a fixed distance from the axis of rotation. Here is my plot of torque vs. This looks like a fairly linear relationship—just like the stretching vs. The slope of this line shows the relationship between twisting angle and torque—I will call this the rotational spring constant k r. For this rubber band, I have a rotational spring constant of 3.
Now I can calculate the total energy with this expression you can derive this for homework. So, how much energy can I store in the rubber band this way? I can twist the rubber band through revolutions without breaking it it broke at rotations. This would be a total energy storage of 7. That's odd. Bibliography These websites are a good place to start gathering information about potential energy and kinetic energy: Rader, A.
Energy of Motion. Retrieved April 5, What is Energy? Does the amount of stretch of a rubber band affect the distance a rubber band will travel? Retrieved April 3, Note: A computerized matching algorithm suggests the above articles. It's not as smart as you are, and it may occasionally give humorous, ridiculous, or even annoying results! Learn more about the News Feed. Materials and Equipment Metric ruler Rubber bands all of the same size and kind Metric tape measure Helper Sidewalk chalk Lab notebook.
Experimental Procedure First write a data table in your lab notebook similar to Table 1. On your ruler, you will be pulling rubber bands back to five different stretch lengths: 10 centimeters cm , 15 cm, 20 cm, 25 cm, or 30 cm.
You will measure how far the rubber bands fly when released from the different stretch lengths and then write your results down in the data table in your lab notebook. Mechanical Engineer. Log in to add favorite More Menu Read More. Mechanical Engineering Technician. Variations You can do a very similar science project to this one by using other types of mechanical systems, such as springs and sling shots. How do the data collected using these other mechanical systems compare to the data collected using rubber bands?
In this experiment you kept the angle and height of launch the same from trial to trial. How would these variables affect the distance the rubber band would travel?
Design a separate experiment to test each of these variables separately. Advanced students can use linear regression to further analyze the data. Can you define an equation that expresses the relationship between potential and kinetic energy in this system? What is the error in your experiment? Are your results significant? Knowing the stretch length and the stretch constant of a rubber band, you can calculate the potential energy the rubber band has, which will let you calculate the kinetic energy the rubber band has when you launch it.
Knowing its kinetic energy, you can calculate how far the rubber band should travel before hitting the ground. How close are your results to predicted results based on these calculations? If your results are different, why do you think this is? View feedback on this project from other users. Can you suggest any improvements or ideas?
Good What is your enthusiasm for science after doing your project? Moderate Compared to a typical science class, please tell us how much you learned doing this project. How is potential energy stored in the can? What kind of energy is the potential energy converted into? What happens when the elastic band is allowed to unwind? Tip: Make sure that the weight hangs down below the point where it is tied.
Details Activity Length 35 mins. Objectives Build a model that stores potential energy and releases kinetic energy. Explain that energy is not created or destroyed, but rather converted from one form to another. Materials Per Tin Can Toy: coffee tin or plastic container drill or punch device 2 elastic bands paperclip tape cotton thread or string small weight e. What To Do Drill or punch a small hole in both ends of the tin, and thread the first elastic band through the hole at the base.
Secure a paperclip to the band outside of the can to prevent the elastic from slipping through the hole. Use tape to secure completely. Thread the weight or washer onto a piece of string, and use that string to tie together the two elastic bands. This should result in the string holding the weight and also joining the free end of the elastic you secured to the tin in step 1 to the second elastic band.
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