Temperature and Heat.
What is Temperature?
Temperature is the reading obtained from a thermometer, which
measures how hot or cold a substance is. At a microscopic level,
temperature describes the average kinetic energy of molecules
within a material or system. It is a measurable physical property
of an object and can be considered with other measurable
physical properties such as velocity, mass, and density (just to
name a few).
Measurement
Temperature is typically seen in units of degrees Celsius or °C (in
some countries the Fahrenheit scale is used); however, in the
scientific community, temperature is seen in SI units—Kelvin or K
(notice it's K not °K). Both Kelvin and Celsius scales have their
advantages and disadvantages:
Celsius vs Kelvin
The Celsius and Kelvin scales increase by the same increments,
meaning that to increase the temperature by 1°C results in the
same increase of 1 K. The major difference is that
when water freezes, a Celsius thermometer will read 0°C, and a
Kelvin thermometer will read 273.15 K. The scales differ by
273.15. Thus, to convert from °C to K simply add 273; if a
thermometer reads 31°C then the temperature in Kelvin is 304K.
Celsius is a much more "user friendly" or intuitive way to measure
temperature; at 0°C—water freezes, and at 100°C—water boils.
Celsius makes sense and it's much easier to judge how 25°C
might feel than how 298 K would, and to be clear, 298 K would
feel fine.
Why bother with Kelvin?
The Kelvin scale happens to be extremely useful (and necessary)
when doing scientific calculations and measurements. Absolute
zero is 0 K (converting to Celsius it's -273.15°C) and is the lowest
temperature the laws of physics allow—there could never be
temperatures below 0 K. In this respect it makes perfect sense to
use the Kelvin scale, 0 being the "absolute" lowest and increasing
from there. For more information (and a handy calculator) visit
the page Kelvin.
What is Temperature?
Temperature is the reading obtained from a thermometer, which
measures how hot or cold a substance is. At a microscopic level,
temperature describes the average kinetic energy of molecules
within a material or system. It is a measurable physical property
of an object and can be considered with other measurable
physical properties such as velocity, mass, and density (just to
name a few).
Measurement
Temperature is typically seen in units of degrees Celsius or °C (in
some countries the Fahrenheit scale is used); however, in the
scientific community, temperature is seen in SI units—Kelvin or K
(notice it's K not °K). Both Kelvin and Celsius scales have their
advantages and disadvantages:
Celsius vs Kelvin
The Celsius and Kelvin scales increase by the same increments,
meaning that to increase the temperature by 1°C results in the
same increase of 1 K. The major difference is that
when water freezes, a Celsius thermometer will read 0°C, and a
Kelvin thermometer will read 273.15 K. The scales differ by
273.15. Thus, to convert from °C to K simply add 273; if a
thermometer reads 31°C then the temperature in Kelvin is 304K.
Celsius is a much more "user friendly" or intuitive way to measure
temperature; at 0°C—water freezes, and at 100°C—water boils.
Celsius makes sense and it's much easier to judge how 25°C
might feel than how 298 K would, and to be clear, 298 K would
feel fine.
Why bother with Kelvin?
The Kelvin scale happens to be extremely useful (and necessary)
when doing scientific calculations and measurements. Absolute
zero is 0 K (converting to Celsius it's -273.15°C) and is the lowest
temperature the laws of physics allow—there could never be
temperatures below 0 K. In this respect it makes perfect sense to
use the Kelvin scale, 0 being the "absolute" lowest and increasing
from there. For more information (and a handy calculator) visit
the page Kelvin.
