Hygrometer, Whirling
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Product Code : SCL-PLE-11601
Quick Answer: The Hygrometer, Whirling, also called a sling psychrometer, is a hand-spun instrument with a dry bulb and a wet bulb thermometer for finding relative humidity and dew point, with a -5 °C to +50 °C range.
Last updated: October 2026
Key Features
- Dry bulb and wet bulb liquid-in-glass thermometers
- Rotating handle with swivel spins the thermometers through the air
- Absorbent cotton sleeve on the wet bulb
- Spirit filled, mercury-free
- Polymer frame with a folding protective case
- Read in 1 °C steps
Technical Specifications
| Specification | Value |
|---|---|
| Sensing | Dual liquid-in-glass thermometers (dry and wet bulb) |
| Range | -5 °C to +50 °C |
| Resolution | 1 °C |
| Operation | Manual rotating handle with swivel |
| Wick | Absorbent cotton sleeve |
| Frame | Impact-resistant polymer with folding case |
| Filling | Spirit, mercury-free |
About This Product
Whirling the thermometers makes water evaporate from the wet bulb, so it reads lower than the dry bulb; the difference between the two is converted to relative humidity. The exercise shows latent heat of vaporisation at work and is used in geography and science lessons on atmospheric moisture, the water cycle and weather recording. Educational Instrument can arrange export supply of the Hygrometer, Whirling to New Zealand, Vietnam, Mauritania, Argentina and Qatar.
Frequently Asked Questions
How is relative humidity found with the Hygrometer, Whirling?
After spinning, the dry and wet bulb readings are compared and the difference is converted to relative humidity, either with a slide rule or a conversion chart.
Does the whirling hygrometer contain mercury?
No. The thermometers are spirit filled and mercury-free.
Related: Physics Lab Equipment, Hygrometer, Wet & Dry Bulb and Thermo-Hygrometer, Digital.
For a quotation on the Hygrometer, Whirling, contact Educational Instrument.
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