Eutrophication STELLA Model: Troubleshooting Guide
The following describe solutions
to problems that students may encounter as they use the eutrophication STELLA
- Students cannot open
the STELLA model:
The demo STELLA program may only allow one model to be open at once. This
may include any blank “New” model. To make sure that no models
are already open, choose “Close” under the “File”
menu, and close anything the program tells you is open. Then choose “Open”
under the same menu, and select the Eutrophication model file.
- Students’ screen
doesn’t resemble the description in the activity:
Students may have inadvertently opened the “Model Construction”
layer or the “Equations” layer of the model. To return to the
“Mapping” layer, find the small white box near the top of the
left-hand grey margin. This box contains a triangle or two. Click on the upward-pointing
triangle. The screen should change. If it still does not look correct, click
on the upward-pointing triangle again. If there is no upward-pointing triangle,
check to make sure that they have opened the Eutrophication model.
- Students cannot move
sliders to desired values:
In the middle of the bottom of the slider box is a small box with a number
inside it. Students can click on this number box and enter a value directly.
- The slider number box
says “eqn. on”:
Students may have accidentally clicked on the small button in the lower left-hand
corner of the slider box (the button with the squiggle on it). Click on this
button again and a number should reappear.
- Students cannot clear
the “Results” graph with the Dynamite tool:
Students may have accidentally “locked” the graph, which prevents
its being erased. Make sure that the icon in the lower left-hand corner of
the graph is an opened lock, not a closed lock. If it is a closed lock, click
once on the icon and it should revert to an open lock.