Overview -- Reverse Engineering

The graph on the left in the Java applet below shows data that you might obtain by watching the tachometer and speedometer of a car as you accelerate from a standing start. At what speeds did the automatic transmission shift gears? What is the ratio between MPH and RPM in first gear? in second gear? in third gear?

Move your cursor onto the top scale on the right of the applet above so that it points at the gear ratio (measured in RPM / MPH) for the low gear. Press and release the mouse button.
Do the same thing using the second scale for the middle gear ratio and using the third scale for the high gear ratio.
Set the speed (in MPH) at which the transmission shifts from low to middle on the fourth scale and set the speed at which the transmission shifts from middle to high on the fifth scale.
You can change any of the settings.
After you are satisfied with the settings move the cursor into the green area and click the mouse button. You will see (in blue) the graph corresponding to your settings. If this graph doesn't match the original then change your settings and try again.

Congratulations! -- You have just completed your first modeling cycle.

You began by looking at some data.
Then you formulated a model -- in this case your model was based on an analogy with bicycle gears and required you to determine from the data five parameters.
You tested the predictions of your model against the data.
If necessary, you modified the model.

You can practice the modeling cycle using the Java applet above. Click on the long blue bar at the bottom of the applet. This will generate a new set of data for a different car and transmission. Go through the modeling cycle for this car and transmission.