Millikan's oil drop experiment explained

[@bustinbustin6487]

2019 HSC student here, thanks for briefly clarifying how Millikan was able to determine the mass. I had always been confused about that.

[@bulidrians2182]

18 min video not sure the word "brief" is appropriate lol.

[@fabienleguen]

What's amazing me is that this setup has the sufficient resolution to charge oil drops with charges of just a few e or even one e ! Knowing that the electron exists, if someone presented me this set-up yesterday, I would have guessed that each individual drop of oil would get charges of millions or billions of e. Then I would have concluded that this set-up won't have the sufficient resolution to detect the gaps between discret charges configurations when plotted on a graph. Did Milikan consider this potential limitation before starting this experiment or did he just went in ? Amazing.

[@OChemRules]

I apologize now for a possibly dumb question but it seems that at minute 14 the "N" value 4 is missing and the value of 5 is labelled as 4. Maybe I am way off but a jump from about 5 on the scale to 8.2 occurs. Divide this difference by 2 and you get about 1.6 x 10E-19

[@KisemboPhysicsAndMath]

Great video. I am inspired to improve on my own videos. Keep it up

[@jenniferprice3877]

Great teaching resource for NSW Physics

[@skeller90]

Can someone explain to me why X-rays (ionization energy), which removes electrons from a atom, can be used to enhance the negative charge of an oil sample? Maybe I misunderstood something in this process and this makes me crazy :S. Thanks for the possible answers! Good day!

[@aelinwhitehorn3526]

Yea sure. The ionising radiation ionises the particles from the air which makes the electrons detach. These then join on to the atoms of the oil droplet making it negatively charged. Hope this helps!

[@何楽川]

top quality video, helps a lot!

[@yasurikressh8325]

Something only a scientist would say: * looks at some dust moving up and down* “yep, it’s a good one”

[@cwj9202]

Excellent video. Thanks.

[@debrafagon9203]

Great video. I really understand this experiment now. Continue making informative content.

[@PhysicsHigh]

Thanks for the feedback. I’m glad it helped.

[@aweasadbek5445]

amazing

[@kevvjj2629]

Great video. I'm teaching A Level physics in the UK and we do the maths - so it was great to see it in this video.

[@andrewnoonan5275]

jumped into it just now , but what does q itself signify-understand the substitutions and principle of equations , but what is q ?

[@HowTo5min-co3ni]

Love you guys💯 Thanks for the awesome explanation.

[@PhysicsHigh]

Thanks for the feedback

[@jhonwask]

Wouldn't the viscosity of air be different at different locations, e.g. high altitude vs. sea-level? What about the air composition of the past compared to the composition of today? Could a vacuum (or near vacuum) be used as the medium, or perhaps a noble gas at atmospheric pressure? I think an experiment of this type is warranted.

[@zeyadwael422]

Masterpiece

[@glenmartin2437]

Thank you. That cleared up a lot.

[@samanthakneeshaw8003]

As always a great resource for my students and us teachers!

[@PhysicsHigh]

Great to hear!

[@camilojoseph6518]

Thank you so much

[@kamranshabeer1157]

Thank you sir

[@mukhtaarjaamac8763]

10¹⁹ where from

[@bimmjim]

I thought Millikan's experiment was done in a vacuum chamber hence there would be no buoyancy or drag. .

[@PhysicsHigh]

No there was air.

[@SimonCrookED]

No, the drag is actually an important part of the experiment.

[@almirbravin1]

Almir Bravin, when the oil drops without the eletric field E ,was stated in the video that the velocity is constant, I din´td get it , and the acceleration of gravity doesn´t it increases the velocity?

[@PhysicsHigh]

The velocity is constant without g as the oil drops reach terminal velocity.