Is It Accurate to Measure the Elementary Charge with Just One Oil Drop?

[tvelev92]

I completed the Millikan oil drop lab in class with as much accuracy as possible. I used the PASCO interface and used a very accurate Air pressure calibration. My final experimental charge of the electron derived from the equation in the lab was, 1.8 x 10 ^-19 C. When I turned in my lab, I was docked points for having a "very rare" one electron on the oil drop analyzed even though the percent discrepancy is something like 12.5 percent compared to the theoretical charge of the electron. Would I be wrong to contest this?

edit- usually the charge contained on one drop is due to several electrons and dividing by the theoretical charge gives you how many electrons are on it. I got one electron on the drop and got docked

 

[Emilyjoint]

how much cahrge did you get on a drop...if it was only 1.8 x 10-19C then it looks strange because that is close to exactly 1 electron

 

[tvelev92]

That is the exact computed number from the equation

 

[Emilyjoint]

wow..that is strange, sounds like you had a drop with exactly one electron on it.
Not impossible but also not likely.
Did you have lots of measurements on drops to get a final answer?

 

[tvelev92]

Took 6 times up and 6 times down averages them separately and computed from there

 

[mfb]

If I remember correctly, in this experiment I had 2 drops with a single electron, too. 2 out of ~30, with most somewhere in the range of 2-10 electrons.

You cannot measure the elementary charge with a single drop only. How many electrons did you have in the other drops?