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Archive for the ‘Science Instruments’ Category

The Millikan Oil Drop Apparatus

The Milikan Oil Drop experiment an experiment where you measure the elementary electric charge of an electron. This is done by examining tiny charged droplets between two electrodes. The plates are charged to the point where the droplets were at mechanical equiplibrium. From this the charge of the electron (based on the size of the droplets and the material of the droplet.).

United Scientific’s Milikan Oil Drop Apparatus allows modern physics students to perform the Oil Drop Experiment in their own lab.


This Milliklan Oil Drop Apparatus is hooked up to a computer via USB cable where the results can be studied. A version with a monitor is also available.  The apparatus consists of an oil drop chamber with a mercury lamp, a digital voltmeter, a CCD camera, an atomizer, and a digital timer.  Software is also included.

The Oil Drop Chamber is made of an accurately dimensioned polymer cyclinder with two precisely machined paralell end plate electrodes. The cylinder has an illumination opening, an observation opening, and a quartz glass window to exclude drafts. The entire oil drop chamber is housed in a cylindrical dreaft shield. Oil drops fall from a an oil mist chamber above the draft shield into the oil drop chamber through a hole of 0.4mm diameter in the uppoer electrode plate. They are illuminated by an LED.

A built in timer allows users to conveniently measuer the time it takes an oil drop to complete a motion through a measured distance. The distance can be measured on the monitor or via the computer link. Voltage is adjusted via the balancing voltage control and the balancing votlage switch. It can be varied from 0-500V with the control knob.

Two methods for measuring the elementary electric charge of an electron are descreibed in the manual: The Balance method and the Ris and Fall Method.

Want to buy the Millikan Oil Drop Experiment Apparatus?



New Measuring Items: Digital Sound Meter & Digital Lux Meter

Sometimes you just need to measure light or sound. Whether you are getting a sunlight reading for a camera shoot or testing out what it really means for the amp to go up to 11, measuring devices can be very useful, and we have just added two digital units for measuring!

First up is the Digital Sound Meter:


This unit measures sound from 30 to 130 dB. For sense of scale 30dB is a whisper at about 6′, while 130dB is 10dB below the ‘say-goodbye-to-your-hearing-if-exposed-even-if-you-are-wearing-hearing-protection’. Keep in mind that the dB scale is logarthmic, so 10dB is quite a lot. But in any case prolonged exposure at anything over 95dB is bad, and 125dB is ‘ow-my-ears-hurt’ level. So this unit covers the ends of the scale quite nicely. Scale is to the .1 dB with accurate of +/-1.5dB.

But what about light? Can we not measure light?

Sure we can, especially with another digital instrument, the Digital Lux Meter


This Lux Meter features a cabled sensor so you can read light levels where you want. It has f different ranges that can cover as low as 0.1 Lux all the way to 100,000 Lux. For perspective a cloudy moonlit night is 0.1 Lux, while a bright sunny day is 50,000 Lux. The Lux scale is not logarithmic as the difference between an overcast day (5,000 lux) and the Sunny day (50,000) is quite measurable.

The Digital Lux Meter is accurate to 3% and has a Min/Max feature for determining highest and lowest light levels. The LED screen is also large and friendly to read in high or low levels of light.

Be sure to check out Spectrum Scientifics other Science Instruments.