# Physics307L:People/Meyers/Millikan Oil Drop Lab Summary II

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MILLIKAN OIL DROP LAB (again)

^{SJK 17:58, 27 November 2010 (EST)}## Contents |

## Purpose

The purpose of this lab was to determine the value of the fundamental charge. A cursory goal was to understand more about the experiment and physics fundamental charge.

## Procedure

The procedure for this lab is posted here

**Procedure Notes**

Three important things that we forgot about on the second day of lab.

- Clean the equipment fully before each use.

- Make sure the focus on the microscope is sharp.

- If there are no droplets after the above two notes are completed, you can remove the cap off the top capacitor plate to aid in production of drops.

## Data

- Particle 3:

Mean fall velocity: 3.918 * 10^{ − 5}*m* / *s*

Mean rise velocity: 8.66 * 10^{ − 5}*m* / *s*

- Particle 4:

Mean fall velocity: 3.036 * 10^{ − 5}*m* / *s*

Mean rise velocity: 1.134 * 10^{ − 4}*m* / *s*

- Particle 5:

Mean fall velocity: 3.269 * 10^{ − 5}*m* / *s*

Mean rise velocity: 1.026 * 10^{ − 4}*m* / *s*

- Particle 7:

Mean fall velocity: 3.595 * 10^{ − 5}*m* / *s*

Mean rise velocity: 1.271 * 10^{ − 4}*m* / *s*

- Particle 8:

Mean fall velocity: 3.150 * 10^{ − 5}*m* / *s*

Mean rise velocity: 3.85 * 10^{ − 5}*m* / *s*

- Particle Thorium:

Mean fall velocity: 3.6250 * 10^{ − 5}*m* / *s*

Mean rise velocity: 4.2860 * 10^{ − 4}*m* / *s*

## Calculation

Using the rise and fall velocities we can calculate the fundamental charge q

I used this equation to calculate the pressure.

Using this equation and a MATLAB program I wrote I calculated to be:

Particle 3:

Particle 4:

Particle 5:

Particle 7:

Particle 8:

Thorium Particle:

Averaged together we get a q of:

## Error

With the accepted value of q as:

This is inside my first standard deviation of mean of my calculated q.

Also the percent error is:

This is very good.

## Conclusion

Compared to the first time we did this lab we have done much better. We found a and a standard deviation that contains the accepted value of . From last time, we changed one fundamental thing, time. We took the time to take more data and make sure that it is good data.

## Citation

1)Pressure versus altitude equation here

2)Altitude of Albuquerque here

3)Wiki math help here

4)Accepted value of q here

## Thanks

1) Nathan for lab help along with data input and help with google docs.

2)Steve Koch for help in trouble shooting the lab.