# Electric Field Hockey*

This is an online simulation that uses the PhET Electric Field Hockey simulation from the University of Colorado.

#### Purpose

To use the electric force to move an electric charge and “score” a goal.

#### Objectives

• To gain experience of the magnitude and direction of the electric force between various charges

#### Theory

The electric force between two point charges is given by the Coulomb’s Law:

$F=k \frac{\left(q_1\right)\left(q_2\right)}{r^2}\;,$

where $k=9.0\times10^{9}$ Nm2/C2, and q1 and q2 are the two charges, and r is the distance between them.

#### Set up

• Open the simulation Electric Field Hockey
• Select “Puck Positive”, “Trace”, and “Field” from the menu on the bottom of the simulation window

#### Activity 1. Score a goal with one barrier

Set the simulation level difficulty to Difficulty 1 and place as many charges as necessary until you “score” a goal. Take a screenshot of the successful goal. (That is your result!)

#### Activity 2. Score a goal with two barriers

Switch to Difficulty 2 level (two barriers) and “score” a goal. Take a screenshot of the successful goal.

#### Extra Activity. Score a goal with three barriers

This activity is extra credit and is optional. Switch to Difficulty 3 and “score” a goal.

#### Results

For each activity, take a screen shot when you “score” the goal. Save them as image files (png, gif, tiff, jpeg, etc.) and post your results either on BB or bring them in paper to class.

#### FAQ

###### Simulation does not open or run

Make sure you have the latest Java JRE installed on your computer.

###### How to take screenshots
• Windows OS: you can take a screen shot by pressing ALT+PRTSC or use the snipping tool. You will have to use an editor to save the file (paintbrush, gimp, etc.)
• MAC OS: press shift+Command+4 for a screen shot. Your image will appear on your desktop in .png format.
###### Submission of results
• Electronic submission: upload your image files on BB in the corresponding lab space
• Paper submission: print out your files and bring them before the beginning of the next lab.