Convert romer to wedgwood easily.
((1 °Rø - 7.5) x 40÷21 + 267.5) / 135 = 1.89 °W
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Ever wondered how 18th-century scientists measured extreme heat before modern thermometers? Picture Josiah Wedgwood (yes, the pottery guy) staring at shrinking clay pieces in a kiln, while Ole Rømer tracked mercury expansion in Copenhagen. Converting between their temperature scales today feels like bridging two different worlds of thermal measurement. Let's explore why this conversion matters and how to do it right.
Unit definitions
What is a romer (°rø)?
Description: Developed by Danish astronomer Ole Christensen Rømer in 1701, this was one of the first standardized temperature scales.
Symbol: °Rø
Common uses: Early meteorological studies, Danish scientific work
Definition: Sets water freezing at 7.5°Rø and boiling at 60°Rø. Divided into 52.5 equal parts between these points.
What is a wedgwood (°w)?
Description: Created by Josiah Wedgwood in 1782 for ceramic kilns.
Symbol: °W
Common uses: Measuring high temperatures in pottery firing
Definition: Based on clay shrinkage. 1°W equals approximately 135°C above Wedgwood's "zero heat" reference (130°C).
Conversion formula
The mathematical relationship between these scales requires two steps:
- Convert Rømer to Celsius: °C = (°Rø - 7.5) × 40/21
- Convert Celsius to Wedgwood: °W = (°C + 267.5) ÷ 135
Combined formula:
°W = (°Rø - 7.5) × 40/21 + 267.5 ÷ 135
Example calculations
Example 1: Convert 25°Rø to Wedgwood
Step 1: (25 - 7.5) × 40/21 = 17.5 × 1.9048 ≈ 33.333°C
Step 2: (33.333 + 267.5) ÷ 135 ≈ 300.833 ÷ 135 ≈ 2.228°W
Example 2: Convert 60°Rø (water boiling point in Rømer scale)
Step 1: (60 - 7.5) × 40/21 = 52.5 × 1.9048 ≈ 100°C
Step 2: (100 + 267.5) ÷ 135 ≈ 367.5 ÷ 135 ≈ 2.722°W
Conversion tables
Rømer to Wedgwood
| Rømer (°Rø) | Wedgwood (°W) |
|---|---|
| 7.5 | 1.981 |
| 10 | 2.016 |
| 20 | 2.160 |
| 30 | 2.304 |
| 40 | 2.448 |
| 50 | 2.593 |
| 60 | 2.722 |
| 70 | 2.867 |
| 80 | 3.011 |
| 90 | 3.156 |
Wedgwood to Rømer
| Wedgwood (°W) | Rømer (°Rø) |
|---|---|
| 1.0 | -5.1 |
| 1.5 | 23.6 |
| 2.0 | 52.3 |
| 2.5 | 81.0 |
| 3.0 | 109.7 |
| 3.5 | 138.4 |
| 4.0 | 167.1 |
Historical context
The Rømer-Wedgwood conversion reveals fascinating stories. Rømer invented his scale while studying the thermal expansion of mercury and wine spirits (yes, alcohol helped create the first practical thermometer). His work directly influenced Fahrenheit, who visited Rømer's lab in 1708. The Danish government officially used Rømer's scale until 1860, making it one of Europe's longest-serving pre-metric standards.
Wedgwood's scale emerged from industrial necessity. As pottery became England's top export, kiln operators needed reliable high-temperature measurements. Wedgwood's clay pellets shrank predictably at specific heats. A 12.0°W reading meant silver would melt (1760°C), crucial for testing kiln performance. Though replaced by pyrometers in the 1850s, his method remained in use until surprisingly 1950s in some Staffordshire potteries.
Fun fact: Converting between these scales was essentially impossible during their inventors lifetimes. Rømer died in 1710, Wedgwood wasn't born until 1730. The benefit of digital conversion tools makes this historical crossover possible today.
Interesting facts
- Alcohol calibration: Rømer's original thermometers used wine spirits instead of mercury.
- Pottery puzzles: Wedgwood's clay test pieces were called "pyrometric beads."
- Fahrenheit's tweak: The Fahrenheit scale kept Rømer's 7.5° freezing point but eliminated fractions by quadrupling scale divisions.
- Industrial espionage: French scientists tried (and failed) to steal Wedgwood's kiln measurement techniques in the 1780s.
- Modern revival: Some Danish craft breweries use Rømer scales for historical accuracy in beer recipes.
FAQ
These conversions are mostly used by historians, ceramics specialists, or enthusiasts studying pre-industrial temperature measurement methods.
No, both were replaced by Celsius and Kelvin by the late 19th century. You'll only encounter them in historical records or niche applications.
Surprisingly precise for their time. Wedgwood's clay shrinkage method could measure temperatures up to 1,300°C within ±10°C accuracy.
Yes. Daniel Fahrenheit visited Rømer in 1708 and later adapted his scale, keeping Rømer's 7.5° as water's freezing point but adjusting the intervals.
Technically yes, but modern ovens use Celsius/Fahrenheit. Some artisanal pottery workshops might reference Wedgwood for tradition's sake.