12 ms·

-10F is -23.33C

by shapefrog 4y ago

-10F is -23.33C

Ndymium 4y ago
OP must have accidentally put in 10°F, which is -12°C.
hackeraccount 4y ago
Also 249.817 K
- shapefrog 4y ago
  Also f'ing freezing.
- adrian_b 4y ago
  As an electronics engineer, I always prefer millivolt to kelvin, so 21.528 mV instead of 249.817 K. Special units for temperature are no more useful than yards or pints.
  - _Microft 4y ago
    The unit here should be meV/k_B instead of mV btw (the latter is proportional to the temperature but doesn't have the unit of a temperature).
    - adrian_b 4y ago
      The convention used by SI to give the name "kelvin" to the unit of temperature and to set its value by giving a certain value to the Boltzmann constant is completely artificial and its only justification is to ensure continuity with a certain historical tradition. A completely equivalent convention would be to give the name "volt" to the unit of temperature and to set its value by giving another value to the Boltzmann constant, numerically equal to what is currently named as the ratio between the Boltzmann constant and the elementary charge. The fact that "volt" is also the name of the unit of electrical voltage does not matter. The name of an unit does not identify the physical quantity measured with it. For each SI unit, there may be many distinct physical quantities that may be measured with it. (This is a very desirable feature of the system, which avoids the proliferation of many arbitrary universal constants in the formulas.) This is actually a fallacy not infrequent at computer programmers, to believe that storing the measurement unit together with a number is enough to unambiguously determine its meaning. In reality, also the measured physical quantity must be known. In many cases the intended physical quantities can be deduced from the context, but there are cases when you have old tables or graphs whose meaning is hard to guess, even when having the measurement units. The unit eV (electron-volt, used for energy) does not belong to the SI, even if its use along SI units is officially tolerated. The same is with the volt as a temperature unit. Like the Fahrenheit degree, it is not an SI unit, but it is possible to use a system of units that differs from SI only by measuring the temperatures in volt. Such an SI alternative has two advantages over SI. One is that in many frequently used formulas a multiplication with an universal constant can be omitted. The second is that it is much easier to have an intuitive understanding of the effects of various temperatures when comparing their magnitudes in volts with the values of some voltages or of some energies expressed in eV. Moreover, the use of the kelvin is not well justified by backward compatibility, because few people are accustomed to think about temperatures expressed in kelvin. Replacing the Fahrenheit degree with the kelvin brings a computational simplification, but if that is the target, going directly to the volt achieves more.
  - PaulDavisThe1st 4y ago
    But yards or pints are really useful units!
    - adrian_b 4y ago
      Like also the Celsius and Fahrenheit degrees, all such traditional units can be useful, but only as long as their use does not involve computations more complex than comparisons, subtractions and additions.

-10F is -23.33C

Ndymium 4y ago

OP must have accidentally put in 10°F, which is -12°C.

hackeraccount 4y ago

Also 249.817 K

shapefrog 4y ago
Also f'ing freezing.
adrian_b 4y ago
As an electronics engineer, I always prefer millivolt to kelvin, so 21.528 mV instead of 249.817 K. Special units for temperature are no more useful than yards or pints.
- _Microft 4y ago
  The unit here should be meV/k_B instead of mV btw (the latter is proportional to the temperature but doesn't have the unit of a temperature).
  - adrian_b 4y ago
    The convention used by SI to give the name "kelvin" to the unit of temperature and to set its value by giving a certain value to the Boltzmann constant is completely artificial and its only justification is to ensure continuity with a certain historical tradition. A completely equivalent convention would be to give the name "volt" to the unit of temperature and to set its value by giving another value to the Boltzmann constant, numerically equal to what is currently named as the ratio between the Boltzmann constant and the elementary charge. The fact that "volt" is also the name of the unit of electrical voltage does not matter. The name of an unit does not identify the physical quantity measured with it. For each SI unit, there may be many distinct physical quantities that may be measured with it. (This is a very desirable feature of the system, which avoids the proliferation of many arbitrary universal constants in the formulas.) This is actually a fallacy not infrequent at computer programmers, to believe that storing the measurement unit together with a number is enough to unambiguously determine its meaning. In reality, also the measured physical quantity must be known. In many cases the intended physical quantities can be deduced from the context, but there are cases when you have old tables or graphs whose meaning is hard to guess, even when having the measurement units. The unit eV (electron-volt, used for energy) does not belong to the SI, even if its use along SI units is officially tolerated. The same is with the volt as a temperature unit. Like the Fahrenheit degree, it is not an SI unit, but it is possible to use a system of units that differs from SI only by measuring the temperatures in volt. Such an SI alternative has two advantages over SI. One is that in many frequently used formulas a multiplication with an universal constant can be omitted. The second is that it is much easier to have an intuitive understanding of the effects of various temperatures when comparing their magnitudes in volts with the values of some voltages or of some energies expressed in eV. Moreover, the use of the kelvin is not well justified by backward compatibility, because few people are accustomed to think about temperatures expressed in kelvin. Replacing the Fahrenheit degree with the kelvin brings a computational simplification, but if that is the target, going directly to the volt achieves more.
- PaulDavisThe1st 4y ago
  But yards or pints are really useful units!
  - adrian_b 4y ago
    Like also the Celsius and Fahrenheit degrees, all such traditional units can be useful, but only as long as their use does not involve computations more complex than comparisons, subtractions and additions.