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I am a new highschool physics instructor and I want to show to my students the basic concept inside the capacitors.

i plan on showing them via simple 2 copper wires side by side each other, supplied with battery, constructed on a breadboard, and measuring via multimeter (which can measure mA), we can measure capacitance.

But I am afraid it would fail, the school does not have that much supply though, I do not have my own multimeter but planning to buy one if somebody here at Physics stackexchange can confirm a setup that I can measure capacitance and tell me the appropriate parameters.

I got this idea from the formula, which states that at some point, at the correct Area and distance to each other, 2 copper wires supplied with voltages can give me capacitance.

enter image description here

So, if you guys have any spare time and device, can you please experiment on what length 2 copper wires, side by side, is enough to measure capacitance, I do not also have any idea if 9V battery is enough, maybe I can series battery to reach higher voltages.

Please help. Thanks!

Setup: enter image description here

Hope somebody can try. Thanks!

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First, you do not connect a DC supply. If you buy a multimeter that can do capacitance all you need is to connect it to the wires. The cost should be around £20. Also, twist the wires together. At 10mm separation you will see almost no capacitance capable of being measured by a cheap multimeter even if the wires are metres in length. Alternatively, just connect a piece of coaxial cable, using the outer shield and inner core to provide capacitance. The typical capacitance is around 100pF per metre.

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What country are you in?
Some quite low cost multimeters can measure capacitance.

I tried two multimeters.
One could measure 0 - 199.0 NF - ie 0.1 NF = 100 pF resolution
The other could measure 0 - 3.999 NF - ie 0.001 NF = 1 pF resolution.

The 0.1 NF resolution meter could not detect short lengths of tightly twisted hookup wire.
The 1 pF resolution meter could detect the presence of about 100mm x 2 wires tightly twisted together - a few pF.

A better capacitor:

I made a ~= 1 NF capacitor with a metal baking tray from an oven and a metal baking pan. Both were aluminum but this is not critical as long as good contact can be made to connecting wires. I added a sheet of "cling-wrap' plastic sheet (used for food storage) to the bottom of the baking pan so it could sit on the tray without making resistive contact. I connected wires to the tray and pan using wood-working clamps (not what I'd usually do :-).

Placing the pan on the tray (with plastic layer between gave good indication on low sensitivity meter and excellent one on high sensitivity meter.

Lifting pan vertically gave smooth (non linear) changes in reading.

Adding sheets of printer paper (70 gsm std paper) sheet by sheet gave a detectable repeatable decrease as more sheets were added.

The 1 pF resolution meter is desirable, but even the 100 pF meter was good enough to demonstrate the various aspects.

Photos may follow.

Example only.

$US10 ebay meter <- Link

20 NF range = 10 pF resolution

enter image description here

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