Capacitor Lab: Inquiry into Capacitor Design
This experiment should improve your familiarity with capacitors and enable you to appreciate what happens when you
change the physical characteristics of a parallel plate capacitor.
After opening this word document put your name and your partner’s name at the top. Open the following webpage, and
then click on the “Run Now” button. When you’re done answering the questions print this page (1 per group)and turn it
in to Mrs. LaFever.
http://phet.colorado.edu/en/simulation/capacitor-lab
Directions:
1. Using the Introduction tab, the voltmeter, and the battery, find variables that are used to design a capacitor.
a. Adjust the battery between -1.5 V and 1.5 V. Record your observations.
b. Connect the meter marked “Plate Charge”, and the Voltmeter (You’ll need to connect the voltmeter to
the plates.) Repeat the first procedure, and make three measurements of Charge Q, and the
corresponding voltage V.
Q /coulombs
V/volts
Capacitance / F
c. Verify that the capacitance agrees with your measured values of Q and V. Show your work. (C = Q/𝛥V)
(you may want to write in your work after you’ve printed the assignment)
d. Disconnect all of the meters and the battery and vary the area of the plates. How does the Capacitance
vary with area A?
e. Vary the separation of the plates. How does the Capacitance vary with the separation.
Capacitance / F
A/m
d/m
a. Using the formula for capacitance of a parallel capacitor, and calculate the constant of proportionality,
ε0. (C = ε0 A/d ) (you may want to write in your work after you’ve printed the assignment)
b. Reconnect the battery and adjust to 1.5 V. Check the View “Electric Field Lines” box, and the Charge
meter box. What happens when the separation of the plates is increased?
c. What happens to the strength of the field when the separation is increased?
2. Summarize your findings from the experiments above.
3. Identify what you would maximize or minimize to make a capacitor with the greatest capacitance. If you wanted
to design a capacitor system to store the greatest energy, what would you use?