Next, test your model to see how the particles move in it.

1. Click LOAD MODEL button and choose the file you saved in the previous step.
2. Make sure the MOUSE-INTERACTION is chosen as "none - let particles move".
3. Click GO/STOP/ADD ELEMENTS button to start your experiment.
4. Record the observations and notes in the questions below the model. Because some particle interactions involve randomness, it's important that you run your experiment more than one time.
5. When you're ready to repeat the experiment, reload your model back by clicking the LOAD MODEL and selecting the model file you saved in the previous step again. 

When you've collected your data, you may want to average some measurement values that changed over the course of many runs. For example, if you ran the model three times with the same starting conditions, you might want to average the value of your dependent variable (pressure, number of molecules, time, etc) over those runs. Furthermore, you may want to consider the following questions as you refine your model:

• Are there changes to the position of the wall or obstacles that you should make for your research question?
• Are there changes to the temperature of the gasses you should make for your research question?
• Do you need to change the number of particles in the air or in containers?

1. Before testing the changes you made, switch the MOUSE-INTERACTION chooser to "big eraser" or something else that is not "none - let particles move" and click the SAVE MODEL button again and give your model another unique, distinguishable name.
2. Repeat steps 1-5, loading the newest model until it:
   • Provides evidence to help you write a scientific explanation the question you proposed for your experiment at the beginning of this activity.
   • Helps you understand important mechanisms at work that explain or cause some (or all) of the patterns in the data.