Group+5


 * Mythbusters & The Scientific Method: //Nan & Amy// **

=1. Explain the myth that you wish to investigate:=

In the movie “The Incredibles”, Mrs. Incredible is a superhuman who has the ability to stretch her body in an infinite number of directions; more specifically she is able to stretch herself lengthwise for up to 30 metres. We will be investigating whether or not her superhero suit is really able to withstand the force of being stretched for 30 metres and if it is, will her suit really be able to shrink back to its original shape like in the movie. =2. What is your prediction and why do you believe this?=

We believe that Mrs. Incredible’s suit will not be able to withstand the force of being stretched for 30 metres. We believe this because even one of the stretchiest fabrics, spandex, should have definite limits with how long it can be stretched. When that limit is reached and more force is applied, the spandex should rip. In the case that the spandex doesn’t rip, we predict that it will not return to its original form.

=3. What are the main physics concepts you will be considering (e.g. Inertia, Newton's 3rd Law, conservation of Momentum, etc.)=

The main physics concepts we will be considering are Newton’s law of universal gravitation, strain, tension and Hooke’s law.

** 4.What are the variables that you will be measuring in your experiment? What are the controls in your experimental setup** . (A control could be that you have to wear rubber gloves so that you don't sweat on your equipment) = Controls =

• control for the thickness of the material • control for the material (i.e. make sure it’s the same type of material) • control for initial length (i.e. where the spandex is attached to the rail and where the weight is attached to the spandex); we have to make sure that the knots we tie do not become loose (**a variable)**

=Variables= • weight attached to the spandex •length of the spandex each time weight is added •the displacement of the spandex from its equilibrium position (same as above)

**5. Describe your experiment in point form ** Steps of the experiment:

• one leg of a pair of spandex leggings will be knotted onto a high railing on the 2nd floor, the other leg will have weights suspended from it, weighing it down towards the 1st floor • we will vary the weight while measuring the length/displacement of the leggings (compared to its initial length without any weights) • we will continue to add weight and record our measurements until the leggings either rip or reach the 1st floor • if it reaches the 1st floor, we will take off the weights and let the leggings attempt to reform and then measure the length

=6. How do you think you will analyze and present your data (types of charts, graphs, pictures, etc.)=

We will analyze and present our data in a table which we will use to graph a stress-strain curve. If the spandex does not rip, we will do calculations concerning its stretch ratio.

COMMENTS:

A good idea. Have you researched the type of material the original suit is made of? Is it really just spandex? There is probably industry standards of stretch and strain of spandex that you can find out about.

Do you have any idea how much weight you will require to stretch the spandex to the lengths you are talking about?