Search results
Results from the WOW.Com Content Network
Under some conditions heat from the measuring instrument can cause a temperature gradient, so the measured temperature is different from the actual temperature of the system. In such a case the measured temperature will vary not only with the temperature of the system, but also with the heat transfer properties of the system.
A meter does not perform its task accurately if it behaves like a reservoir of the state variable it is trying to measure. If, for example, a thermometer, were to act as a temperature reservoir it would alter the temperature of the system being measured, and the reading would be incorrect.
In this example the humidity ratio is 0.0126 kg water per kg dry air. Determining the effect of temperature change on relative humidity: For air of a fixed water composition or moisture ratio, find the starting relative humidity from the intersection of the wet and dry bulb temperature lines. Using the conditions from the previous example, the ...
Anemometers are also used to measure wind speed and indoor airflow. There are a variety of types, including straight probe anemometers, designed to measure air velocity, differential pressure, temperature, and humidity; rotating vane anemometers, used for measuring air velocity and volumetric flow; and hot-sphere anemometers.
Thermometers are used in roadways in cold weather climates to help determine if icing conditions exist. Indoors, thermistors are used in climate control systems such as air conditioners, freezers, heaters, refrigerators, and water heaters. [56] Galileo thermometers are used to measure indoor air temperature, due to their limited measurement range.
In thermodynamics, the volume of a system is an important extensive parameter for describing its thermodynamic state. The specific volume, an intensive property, is the system's volume per unit mass. Volume is a function of state and is interdependent with other thermodynamic properties such as pressure and temperature.
In oceanography a common unit to measure volume transport (volume of water transported by a current for example) is a sverdrup (Sv) equivalent to 10 6 m 3 /s. Primary flow element [ edit ]
The maximum amount of water vapor that can be present in a given volume of air varies greatly by temperature; cold air can contain a lower mass of water per unit volume than hot air. Thus a change in the temperature can change the humidity. A prototype hygrometer was invented by Leonardo da Vinci in 1480.