Temperature

Temperature measurements and units of measure.

• F = C(9/5) + 32 = Fahrenheit
• C = (F-32)5/9 = Celsius
• K = C + 273.15 = Kelvin. The official SI/metric unit of measure for temperature.
• R = F + 459.67 = Rankine. There are others too but only F, C, and K are common.

I am fine with the convention in plain English is to say "six degrees Celsius" or "six degrees Fahrenheit" or "six kelvins", but I abhor the convention of printing "6 °C" or "6 °F". So, since this is my site, I simply write "6 C" or "6 F", just like the standard of writing "6 K".

Example Temperatures

I've listed these values as an exercise to help me get a feel for the relation between Celsius and Fahrenheit.

• -273.15 C = -459.67 F = 0 K = 0 R. Absolute zero.
• ...
• -50 C = -58 F.
• -45 C = -49 F.
• -40 C = -40 F. Coincidence.
• -35 C = -31 F.
• -30 C = -22 F.
• -25 C = -13 F.
• -20 C = -4 F.
• -17.78 C = 0 F = 459.67 R. One story holds that Fahrenheit referenced this as the point where equal amounts of salt and water melt. Freezer refrigeration should be around this temperature.
• -15 C = 5 F.
• -10 C = 14 F.
• -5 C = 23 F.
• 0 C = 32 F = 273.15 K. Freezing point of water at 1 atm. Meat refrigeration should be around this temperature.
• 5 C = 41 F. Regular refrigeration should be around this temperature.
• 7 C = 45 F. Milk should be kept below this temperature.
• 10 C = 50 F. Vegetable refrigeration should be this temperature.
• 15 C = 59 F.
• 20 C = 68 F. Common room temperature. Cold nerve receptors react to temperatures below this point. Common legal minimum temperature to be maintained by landlords
• 25 C = 77 F. Common room temperature. Common tropical fish tank temperature.
• 30 C = 86 F
• 32 C = 90 F. Hot nerve receptors react to temperatures above this point.
• 35 C = 95 F
• 37 C = 98.6 F. Common figure for human core temperature, although statistically it is actually 36.8±0.7 C = 98.2±1.3 F.
• 40 C = 104 F.
• 45 C = 113 F. Pain nerve receptors react to temperatures above this point.
• 50 C = 122 F. Mammalian muscle becomes rigid.
• ...
• 100 C = 212 F. Boiling point of water at 1 atm.
• 125 C = 257 F. Common baking temperature.
• 150 C = 302 F. Common baking temperature.
• 175 C = 347 F. Common baking temperature.
• 200 C = 392 F. Common baking temperature.
• 225 C = 437 F. Common baking temperature.
• 233 C = 451 F. The flash point or auto-ignition point of paper as made famous by Fahrensheit 451, a 1953 book by Ray Bradbury.
• 250 C = 482 F. Common baking temperature.
• ...
• 1668 C = 3034 F = 1941 K. Titanium melts.
• 5527 C = 9980 F = 5800 K. Surface of the sun.

Outside temperature: 40s dangerous, 30s hot, 20s nice, 10s cool, 0s freezing, -10s dangerous.

Page Modified: (Hand noted: 2007-10-24 05:11:40Z) (Auto noted: 2007-11-17 06:22:52Z)