Screen shot of a charged particle orbiting a central charge (Trajectory: What is Wrong?).

# What is Wrong: Finding (intentional) Errors in Electrostatics Models

Students often believe that simulations are correct. They don't recognize that the simulation is only as good as the programmer. These examples show simulations where the physics is incorrect and ask students to make the necessary measurements to determine what is wrong. Navigate to the simulations by opening the folder and then double-clicking on the green triangle to launch. If EJS is installed, they can right-click on the simulation and "Open EJS model" to see the computational model.

#### What is Wrong?

- Coulomb Force (Coulomb's Law)
- Point Charge (Coulomb's Law, Electric Field)
- Dipole Trajectory (Electric Field)
- Electric Field Detector (Electric Field)
- Trajectory (Potential)
- Two Charges (Potential and Electric Field)

Information about EJS is available at: <http://www.um.es/fem/Ejs/> and in the OSP ComPADRE collection <http://www.compadre.org/OSP/>.