Millikan Oil Drop Apparatus – SS2438 Electron Charge Experiment with ±450V Variable Power Supply

Millikan Oil Drop Apparatus – Model SS2438

Reproduce one of the most important experiments in modern physics.

The Sci-Supply SS2438 Millikan Oil Drop Apparatus is a complete, self-contained instrument designed to replicate Robert Millikan’s 1909 experiment for determining the elementary charge of the electron. This robust, classroom-ready system allows students to directly measure the quantization of electric charge through precise observation of charged oil droplets in a controlled electric field.

Designed for upper-level high school and undergraduate physics laboratories, the SS2438 combines a precision oil drop chamber, illuminated viewing system, calibrated microscope with reticule, and an adjustable high-voltage DC power supply in a compact aluminum enclosure.

What Students Measure

Students determine:

• Gravitational fall velocity (Vg)

• Electrically driven rise velocity (VE)

• Applied plate voltage (0 to ±450V DC)

From these measurements, students calculate:

• Oil drop radius (via Stokes’ Law)

• Total charge on each droplet

• Experimental value of the elementary charge (e)

• Percent error relative to the accepted value (1.602 × 10⁻¹⁹ C)

The apparatus supports repeated trials for multiple droplets to observe charge quantization.

Key Features

• Continuously Variable ±450V DC Power Supply with front-panel voltage adjustment and panel voltmeter
• Three-Position Polarity Switch (Positive / Off / Negative)
• 5.0 ± 0.2 mm Plate Separation for controlled electric field strength
• Integrated LED Illumination System
• 30x Microscope with Calibrated Reticule
• 2.0 mm Vertical Field of View with 0.5 mm Graduations (±0.01 mm)
• Compact, Durable Aluminum Enclosure for classroom longevity
• Leveling Feet with Bubble Level for accurate vertical alignment

Technical Specifications

• Input Power: 120 VAC, 60 Hz

• Plate Voltage Range: 0 – ±450 VDC

• Plate Separation: 5.0 ± 0.2 mm

• Microscope Magnification: 30x

• Microscope Field of View: ≥ 3 mm

• Eyepiece Reticule: 2.0 mm scale in 0.5 mm increments

• Operating Conditions: −10°C to +40°C, RH < 85%

• Dimensions: 320 mm × 220 mm × 190 mm

• Weight: ~4 kg

Ideal For

• AP Physics C Labs

• College General Physics

• Modern Physics Courses

• Undergraduate Laboratory Instruction

• Demonstrations of Charge Quantization

• Advanced STEM Programs

Classroom Ready

The SS2438 includes a full operator’s manual with:

• Experimental theory

• Setup instructions

• Measurement procedure

• Sample data set

• Schematic diagram

The apparatus is designed for repeated instructional use and routine laboratory sessions.

Included Components
Double throat pipe atomizer
2 Drams of oil
Complete instruction manual containing complete setup and sample experiment guide