Build Your Own Parallel Plate Capacitor (21:57)
A real parallel plate capacitor built from aluminum foil and printer paper is used to measure the dielectric constant of paper by hand, turning the ideal parallel plate capacitor equation C = κε_0A/d into an actual physics experiment instead of just a formula on a page. The video walks through linearizing real capacitance data, solving for the dielectric constant from the slope of a best fit line, and then shows why the results don't perfectly match the ideal model due to fringing electric fields at the edges of the plates. It is a hands-on capacitance demonstration built for AP Physics 2 and AP Physics C: Electricity and Magnetism students who want to see capacitance and dielectric constant measured in the real world, not just calculated in a textbook.
Chapters:
0:00 Reviewing the Ideal Parallel Plate Capacitor Equation
1:07 Building a Homemade Capacitor, and Measuring Its Plate Area
3:20 Flattening the Capacitor and Measuring Capacitance with a Multimeter
6:41 Linearizing the Data to Solve for the Dielectric Constant
8:40 Measuring the Distance Between the Plates
9:54 Graphing the Data and Finding the Slope of the Best Fit Line
11:22 Checking the Units: Farad-Meters vs. Coulombs Squared per Newton
14:50 Solving for the Dielectric Constant of Printer Paper
16:16 Why the Data Isn't Perfectly Linear: Ideal vs. Real Capacitors
20:28 The Non-Zero Y-Intercept, and Limitations of the Experiment
Chapters:
0:00 Reviewing the Ideal Parallel Plate Capacitor Equation
1:07 Building a Homemade Capacitor, and Measuring Its Plate Area
3:20 Flattening the Capacitor and Measuring Capacitance with a Multimeter
6:41 Linearizing the Data to Solve for the Dielectric Constant
8:40 Measuring the Distance Between the Plates
9:54 Graphing the Data and Finding the Slope of the Best Fit Line
11:22 Checking the Units: Farad-Meters vs. Coulombs Squared per Newton
14:50 Solving for the Dielectric Constant of Printer Paper
16:16 Why the Data Isn't Perfectly Linear: Ideal vs. Real Capacitors
20:28 The Non-Zero Y-Intercept, and Limitations of the Experiment
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- Thank you to Christopher Becke, Nick Gillies, and Ted Anderson for being my Quality Control Team for this video.