Crookes Radiometer
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Product Code : SCL-PLE-11567
Quick Answer: The Crookes Radiometer is a sealed glass bulb holding a partial vacuum and four black-and-white metal vanes on a spindle. In sunlight or lamp light the vanes spin, showing light energy turned into mechanical motion.
Last updated: 18 October 2026
Key Features
- Four vanes with black and white surfaces on a rotating spindle.
- Sealed glass bulb with a low-pressure interior.
- Turns in sunlight or lamp light; no electricity needed.
- Rotation speed changes with light intensity.
Technical Specifications
| Specification | Value |
|---|---|
| Bulb | Sealed glass bulb, partial vacuum |
| Vanes | Four metal vanes, black and white surfaces |
| Mounting | Rotating spindle |
| Drive | Sunlight or lamp light |
How It Is Used
Stand the radiometer where sunlight or lamp light falls directly on the vanes and watch them start to turn. Comparing bright and dim light shows the speed changing, which leads into a discussion of why the black surfaces absorb more heat than the white ones. Handle the glass carefully and keep it away from direct heating sources.
Frequently Asked Questions
Why do the vanes of the Crookes Radiometer turn?
The black surfaces absorb more heat than the white ones, and the temperature difference creates a pressure imbalance in the low-pressure gas inside the bulb that pushes the vanes round.
Does the Crookes Radiometer need electricity?
No. It runs on sunlight or the light from a lamp.
Related Physics Lab Equipment
See the full physics lab equipment range, or these related heat and light energy apparatus:
- Heat Absorption & Radiation Comparator
- Heat Absorption Model
- Leslie Cube 100mm sides
- Light Energy Kit
- Vacuum Pump, Hand
Institutions and distributors in Kyrgyzstan, North Macedonia, Uzbekistan, Papua New Guinea, Bosnia and Herzegovina and Saudi Arabia can request an export quotation for the Crookes Radiometer.
For a quotation on the Crookes Radiometer, contact JLab India on +91-8569909696.
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