Troubleshooting Millikan's Oil Drop Experiment for A Level Physics Coursework

[jaderberg]

Im doing millikan's oil drop experiment as my A level physics coursework to eventually calculate the electronic charge. I am fine with all the theory but what I am really struggling with is the actual practical experiment.

I have seen the oil drops a lot and have managed to manipulate them using a voltage however now when I've come back to the experiment after the weekend i can't see anything and if i do see something its just a really faint cloud of oil drops where i can't pick out a single one to analyse. Why is it so temperamental?

Also i got some initial results for oil drops (which came out to be about 2micrometers radius) under a voltage of around 200v but the charge was far too high (approximate to 100-200 electrons). I hooked up the apparatus to a higher voltage and tried to take some results (at about 1000-2000V) but didnt get much...are all my oil drops too highly charged? I really want to isolate and analyse some which only have a few electrons on them but this seems impossible. Would removing the rubber end of the atomiser stop the oil drops from being so highly charged?

Any help would be really appreciated as well as any practical tips for the experiment (i only have 4 hours left!)

Thanks

 

[Valerie Park]

in advance!It can be difficult to work with oil drops due to their temperamental nature. It is likely that the oil drops are becoming too highly charged when exposed to high voltages, which could explain why they become difficult to isolate and analyse. You could try removing the rubber end of the atomizer to see if it helps reduce the charge on the oil drops, but this may not be enough. Another practical tip is to try and make sure that your oil droplets are of a consistent size. This can be done by adjusting the viscosity of the oil and/or the size of the nozzle opening. Additionally, you can try increasing the humidity of the room to make the oil droplets more visible. Finally, it is important to keep in mind that the results of the experiment can be affected by air currents, so be sure to work in a space with minimal air movement.

 

[charng]

First of all, it is important to note that the Millikan's oil drop experiment is a very sensitive experiment and requires careful manipulation and precise measurements. It is not uncommon for students to face difficulties in conducting this experiment, so do not get discouraged.

One possible reason for your difficulty in seeing the oil drops could be contamination of the oil or the apparatus. Make sure to clean the apparatus thoroughly before each use and use a fresh batch of oil. It is also important to use a clean and dust-free environment for the experiment.

In regards to the high charge on your oil drops, it is possible that the rubber end of the atomizer is contributing to the high charge. Removing it may help reduce the charge on the oil drops. However, it is also important to check the settings on your voltage source and ensure that it is not set too high.

Some practical tips for the experiment include using a light source to make the oil drops more visible, using a microscope to aid in seeing the drops, and taking multiple readings and averaging them for more accurate results.

It is also important to carefully follow the steps of the experiment and double-check your calculations. If you are still struggling, do not hesitate to reach out to your teacher or a lab assistant for assistance. Good luck with your experiment!