Understanding Calories per Second-Centimetre-Degree Celsius to Watts per Metre-Kelvin Conversion
The calorie per second-centimetre-degree Celsius, cal/(s-cm-°C), is the CGS unit of thermal conductivity that populates many classic physics and chemistry reference tables. The watt per metre-kelvin, W/(m-K), is the SI unit used on modern material datasheets worldwide. Because the calorie is fixed at exactly 4.184 joules, this conversion is exact and frequently needed when digitizing older conductivity data into SI-based simulations.
Conversion Formula
To convert Calories per Second-Centimetre-Degree Celsius to Watts per Metre-Kelvin, multiply by this factor:
Step-by-Step Example
Convert 25 Calories per Second-Centimetre-Degree Celsius to Watts per Metre-Kelvin.
How to Convert Calories per Second-Centimetre-Degree Celsius to Watts per Metre-Kelvin
Convert a CGS conductivity to the SI standard with these steps.
- Begin with the value: Note the conductivity in cal/(s-cm-°C), for example 25.
- Multiply by 418.4: This exact factor gives W/(m-K) per cal/(s-cm-°C).
- Compute: .
- State the answer: 25 cal/(s-cm-°C) equals 10,460 W/(m-K).
Calories per Second-Centimetre-Degree Celsius to Watts per Metre-Kelvin conversion table
| Calories per Second-Centimetre-Degree Celsius (cal/(s-cm-°C)) | Watts per Metre-Kelvin (W/(m-K)) |
|---|---|
| 0 | 0 |
| 1 | 418.4 |
| 2 | 836.8 |
| 3 | 1255.2 |
| 4 | 1673.6 |
| 5 | 2092 |
| 6 | 2510.4 |
| 7 | 2928.8 |
| 8 | 3347.2 |
| 9 | 3765.6 |
| 10 | 4184 |
| 15 | 6276 |
| 20 | 8368 |
| 25 | 10460 |
| 30 | 12552 |
| 40 | 16736 |
| 50 | 20920 |
| 60 | 25104 |
| 70 | 29288 |
| 80 | 33472 |
| 90 | 37656 |
| 100 | 41840 |
| 150 | 62760 |
| 200 | 83680 |
| 250 | 104600 |
| 300 | 125520 |
| 400 | 167360 |
| 500 | 209200 |
| 600 | 251040 |
| 700 | 292880 |
| 800 | 334720 |
| 900 | 376560 |
| 1000 | 418400 |
| 2000 | 836800 |
| 3000 | 1255200 |
| 4000 | 1673600 |
| 5000 | 2092000 |
| 10000 | 4184000 |
| 25000 | 10460000 |
| 50000 | 20920000 |
| 100000 | 41840000 |
| 250000 | 104600000 |
| 500000 | 209200000 |
| 1000000 | 418400000 |
What is the Calorie per Second-Centimetre-Degree Celsius?
The calorie per second-centimetre-degree Celsius is the CGS-based unit of thermal conductivity, historically common in physics and physical-chemistry literature. It measures the heat in calories flowing per second through a one-centimetre thickness for each degree Celsius of temperature difference.
Definition
One calorie per second-centimetre-degree Celsius represents a heat flow of one calorie per second through a one-centimetre cube per degree Celsius across it. Using the thermochemical calorie (4.184 J):
The value follows from 4.184 J/s per (0.01 m · 1 K) = 4.184 ÷ 0.01 = 418.4 W/(m·K). If the International Table calorie (4.1868 J) is used instead, the factor is 418.68 W/(m·K).
Origin and History
The unit arose in the CGS era, when heat was measured in calories, lengths in centimetres and temperature in degrees Celsius. It appears throughout older thermal-conductivity tables and heat-transfer texts, especially in chemistry and metallurgy, before the watt per metre-kelvin became standard.
Law and Notable Facts
Though largely superseded by SI, the unit is still encountered in legacy data and some scientific traditions. Its large size is convenient for metals: because 1 cal/(s·cm·°C) equals 418.4 W/(m·K), even highly conductive copper is under 1 in these units, whereas most materials are small fractions.
Real-World Examples and Conversions
- Copper conducts at about 0.94 cal/(s·cm·°C), i.e. roughly 400 W/(m·K).
- Iron is about 0.18 cal/(s·cm·°C).
- Water is roughly 0.0014 cal/(s·cm·°C).
- 1 cal/(s·cm·°C) = 418.4 W/(m·K); conversely 1 W/(m·K) ≈ 0.00239 cal/(s·cm·°C).
What is the Watt per Metre-Kelvin?
The watt per metre-kelvin is the SI coherent unit of thermal conductivity, quantifying how readily a material conducts heat. It expresses the rate of heat flow through a material per unit thickness for each degree of temperature difference across it.
Definition
A material has a thermal conductivity of one watt per metre-kelvin if a temperature gradient of one kelvin per metre drives a heat flux of one watt per square metre through it:
Because a temperature difference of one kelvin equals one degree Celsius, W/(m·K) and W/(m·°C) are numerically identical.
Origin and History
The unit follows directly from Fourier's law of heat conduction, published by Joseph Fourier in his 1822 Théorie analytique de la chaleur, which states that heat flux is proportional to the negative temperature gradient. The proportionality constant is the thermal conductivity, and it acquired its coherent SI form once the watt, metre and kelvin were established within the International System of Units.
Law and Notable Facts
The watt per metre-kelvin is the standard SI unit for material property tables worldwide. Thermal conductivity spans an enormous range: from aerogels near 0.02 W/(m·K), among the best solid insulators, to diamond at roughly 2000 W/(m·K), the highest of any bulk natural material.
Real-World Examples and Conversions
- Still air conducts heat at about 0.026 W/(m·K); water at about 0.6 W/(m·K).
- Common window glass is near 1.0 W/(m·K); stainless steel about 15 W/(m·K).
- Copper reaches roughly 400 W/(m·K), which is why it is used for heat sinks.
- 1 W/(m·K) = 1000 mW/(m·K) ≈ 0.5778 BTU/(h·ft·°F).
Frequently Asked Questions
What is one cal/(s-cm-°C) in W/(m-K)?
It equals exactly 418.4 W/(m-K), because the thermochemical calorie is defined as 4.184 J and the unit scales by a factor of 100 from centimetres to metres.
How do I convert W/(m-K) back to cal/(s-cm-°C)?
Multiply by 0.002390057. For example, 418.4 W/(m-K) returns to exactly 1 cal/(s-cm-°C).
Why is this conversion exact rather than approximate?
The calorie used here (thermochemical) has an exact definition of 4.184 joules, and metre/second/kelvin relationships to the CGS units are also exact, so no rounding is introduced.
In which fields does this conversion appear?
It is common in materials science, geophysics, and heat-transfer engineering when older CGS tables of metal, rock, or ceramic conductivity must be brought into SI-based models.
What everyday material sits near 418.4 W/(m-K)?
That is roughly the conductivity of silver, one of the best metallic conductors of heat, so 1 cal/(s-cm-°C) corresponds to an exceptionally conductive substance.
People also convert
Complete Calories per Second-Centimetre-Degree Celsius conversion table
| Unit | Result |
|---|---|
| Watts per Metre-Kelvin (W/(m-K)) | 418.4 W/(m-K) |
| Milliwatts per Metre-Kelvin (mW/(m-K)) | 418400 mW/(m-K) |
| BTU per Hour-Foot-Degree Fahrenheit (BTU/(h-ft-°F)) | 241.7471 BTU/(h-ft-°F) |
| BTU-Inch per Hour-Square Foot-Degree Fahrenheit (BTU-in/(h-ft2-°F)) | 2900.965 BTU-in/(h-ft2-°F) |