Sunday, February 21, 2010

The Conservation of Energy!

Part A:
This is what I learned about the Conservation of Energy.  When we were first introduced to energy we asked, "What is energy?"  Well to be honest I found that question very hard to answer.  I sat in my seat and thought about electricity, springs, elastics, fuel, and my favorite, food.  I asked, "What do all of these things have in common?"  Well we later learned that energy is the potential to "do work."  For example:  By lifting weights the energy I use from my food intake is used to lift the weight and therefore give it potential energy due to its height in relation to a reference point that can be the ground, or where the weight started.  The energy I put on the weight did not disappear, in fact, energy never disappears in our universe.  The energy actually it is transferred into another form, this being kinetic (motion), elastic (spring or stretching related), potential (in relation to a specific height), or internal (as in various forms of friction that can lead to heat).  Energy can be stored in different forms, but it can never disappear.  Although by the end of my work out I am very tired and energy depleted, the energy I have lost has actually only been transported to other forms around me.  This concept is useful while we solve problems that are asking about energy.  We can set up equations to find the quantity of various forms of energy at different periods of time in Joules (Newtons x meters).  This quantity represents "work" which can be found by finding the product of Force (N) and distance (m).  The work that is done happens over a period of time, which gives us a rate of work accomplished, which is known as power.  The unit of power is Nm/time (Watts - W).  What I really enjoy about energy is that the quantitative value of energy is constant throughout the situation.  When we began we made energy charts where we were required to identify the system and show where all of the energy dissipated.  After grasping this concept options of problems we can solve become infinite with the simple concept that the original energy will be present in the final result.  Since Joules is a universal unit it can be easily tracked throughout the problem.  

Originally when we began studying the concept of the conservation of energy I had a hard time interpreting and drawing qualitative graphs of energy problems.  Part of my problem was that I did not originally understand what each form of energy really was.  Through out the "clicker quiz," the class work, and our Physics Quest, I was especially able to grasp the concepts through contemplation.  The process was not easy and that Physics Quest took much more time than it would take me now, but now I go into problems with a more open mind and consider any possible transfer of energy.  Our Physics Quest had several difficult problems that cause me to create a checklist of different forms of energy.  This technique has helped me tremendously, and I would recommend it to all of you!  If you go down the line of different forms of energy in your head, it will be much easier to understand the problem, and you will make far fewer mistakes.

My problem-solving skills have continued to improve.  I have been more "snappy" toward understanding how to set equations equal to each other and have items cancel out.  This has been especially important in this unit because we have the constant variable that is the energy that never leaves the system.  This forces us to work while setting the original energies equal to find the current states of energy.  Once I understood the qualitative concepts of energy, the quantitative was very natural. 

Part B:
An example of how our energy knowledge is applied to our everyday life can be found while watching many of the winter sports on TV.  A great example of this was while Shaun White, an American half pipe expert, completed his two runs.  The start of the half pipe is uphill which gives him potential energy due to gravity, his mass, and height.  Shaun White left the start and proceeded down hill, gaining Kinetic energy.  As he changed elevations during his jumps his Kinetic energy and potential energy changed, but the sum of the energy remained constant.  His board made friction with the snow and left Internal energy.  We know that the total energy of the system was constant throughout each of his runs, although it was constantly changing states. 


  1. Hey Eric, Good Job! Your explanation of what you learned and your journey through this unit was very interesting. In my opinion, your explanation gave all the right amount of detail but was concise and not superfluous. Just one small thing: On the second paragraph of part a, I think it would be good if you could add "the" when you make the statement "Through out ___ 'clicker quiz,'." Besides this, I think your reflection was great!

  2. Outstanding reflection!! In your application particularly liked the reference to winter sports!