Physics307L:People/Knockel/Notebook/070912: Difference between revisions
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*<math>p=8.5\times10^4 Pa</math> (air pressure in Albuquerque) | *<math>p=8.5\times10^4 Pa</math> (air pressure in Albuquerque) | ||
*<math>b=8.20\times10^{-3} Pa\cdot m</math> (some stupid constant) | *<math>b=8.20\times10^{-3} Pa\cdot m</math> (some stupid constant) | ||
===Formula=== | |||
===Procedure=== | ===Procedure=== | ||
We select a drop that is barely falling through the | We spray droplets of oil into the viewing chamber using the atomizer by pumping droplet rich air into it. We then select a drop that is barely falling through the viewing chamber in no electric field (we want drops that have little mass). We measure the speed at which it falls, <math>v_f</math>. We then create an electric field that causes the droplet to rise and measure the speed, <math>v_r</math>. We take many measurements of both of these speeds over and over on the same droplet. We will periodically introduce alpha particles which will change the charge of the oil droplet to be either more positive or negative depending on how the collision between the oil and alpha particles occur. We will record the new velocities. | ||
===Data=== | ===Data=== | ||
=== | ===Results=== | ||
===Analysis=== | ===Analysis/Conclusions=== | ||
Revision as of 14:38, 15 September 2007
Millikan's oil drop experiment (charge of the electron)
Experimenters: Nikolai Joseph and Bradley Knockel
Goal
I want to measure the charge of an electron by measuring the charge on a bunch of oil droplets and seeing if I can find that my calculated charges are integer multiples of some fundamental charge. The actual value is [math]\displaystyle{ e=1.60\times10^{-19} C }[/math].
Equipment
- power source (should go up to 500 V direct current)
- atomizer (to spray oil droplets)
- 2 multimeters
- banana cords
- banana plug patch cords
- DC transformer for light
- micrometer
- THE MILLIKAN DEVICE! (scope, viewing chamber, light, level, focusing wire, thermistor, etc.) (Model AP-8210 by PASCO scientific)
Setup
- plugged in power supply to wall and Millikan device (turned off)
- hooked up multimeter using banana plug patch cords to check voltage from power supply
- leveled the Millikan device
- plugged in the light using DC transformer
- focused viewing scope with focusing wire
- aimed the lamp/light/filament
- turned on power supply and checked it's voltage using first multimeter
- attached another multimeter to the thermistor
Values (given to as many significant figures as are reasonably certain)
- [math]\displaystyle{ d=7.59\times 10^{-3} m }[/math] (plastic spacer width using micrometer)
- [math]\displaystyle{ \rho=8.86\times 10^2 \frac{kg}{m^3} }[/math] (density of oil given on bottle)
- [math]\displaystyle{ g=9.8 \frac{m}{s^2} }[/math] (gravitational acceleration)
- [math]\displaystyle{ p=8.5\times10^4 Pa }[/math] (air pressure in Albuquerque)
- [math]\displaystyle{ b=8.20\times10^{-3} Pa\cdot m }[/math] (some stupid constant)
Formula
Procedure
We spray droplets of oil into the viewing chamber using the atomizer by pumping droplet rich air into it. We then select a drop that is barely falling through the viewing chamber in no electric field (we want drops that have little mass). We measure the speed at which it falls, [math]\displaystyle{ v_f }[/math]. We then create an electric field that causes the droplet to rise and measure the speed, [math]\displaystyle{ v_r }[/math]. We take many measurements of both of these speeds over and over on the same droplet. We will periodically introduce alpha particles which will change the charge of the oil droplet to be either more positive or negative depending on how the collision between the oil and alpha particles occur. We will record the new velocities.
