Since this is a basic model, it can be expanded to illustrate the loss of energy due to frictional forces, the affect atmospheric height has upon the frictional forces, the type of material that is falling through the atmosphere Just imagine the critical thinking that must occur in this type of environment. Once the model is laid out based upon current thought, the "what if scenarios can begin."

The picture on the left represents the model interface that explores Kinetic Energy and Potential Energy. I would like for you to down load the zipped model and explore how Potential Energy is transformed to Kinetic Energy in a falling object. This model is a classical exploration of the transformation.

Once the model is built, you can explore the different situations. In this case you can use the slider buttons to change the mass and acceleration of the object. How do these changes affect the total energy of the model?

You may click on the Graph, "Model Level," and "Information" buttons on the left image to learn more.During the next few weeks we may be using different models to explore energy. You may use the models for exploration within your own class. For an assignment you will need to do the following:

1. Download the run-time (no charge) STELLA software from High-Performace Systems at http://www.hps-inc.com

2. Download the model which is in a zipped/stuffed format (KE_PE_Model.sit)

3. Download the Expander program from Aladdin Software at http://www.aladdinsys.com

4. Unstuff or unzip the model using the Expander program or any other one of your choice (This model was developed with the Macintosh version of STELLA 7.01. It can be opened by the PC version. Once unzipped, you may have to add the .STM extension to the file name for the PC version to recognize the file.

5. Open the model using the STELLA Software.

6. Email to me the answer to these questions.

• What type of graph is produced by KE and PE in the system
• At what height is the object at 10.22 seconds and what is the KE and PE at this time.

Once the model has been opened, click on the ? to learn why the energy levels and acceleration are (-).