Temperature Concepts and Measurement Flashcards
What is temperature?
Unlike heat, temperature is not a form of energy; however, temperature is related to the amount of energy in a substance. Temperature is a measure of the average kinetic energy of individual molecules in matter. (Remember that matter is mass that assumes a physical shape and occupies space.) Thus, temperature is a measure of heat.
What is absolute zero?
The temperature at which atomic and molecular motion in matter completely stops is absolute zero, or 0 absolute temperature. This value on three commonly encountered temperature-measuring scales is –273° Celsius (C), –459.67° Fahrenheit (F), and 0 Kelvin
What is the Fahrenheit scale?
The Fahrenheit scale is named for its developer, Daniel G. Fahrenheit, a German physicist (1686–1736). This temperature scale places the melting point of ice at 32°F, separated by 180 subdivisions from the boiling point of water at 212°F. Note that ice has only one melting point, but water has many freezing points, ranging from 32°F down to –40°F, depending on its purity, its volume, and certain conditions in the atmosphere.
What is the Celsius scale?
About a year after the adoption of the Fahrenheit scale, Swedish astronomer Anders Celsius (1701–1744) developed the Celsius scale (formerly centigrade). He placed the melting point of ice at 0°C and the boiling temperature of water at sea level at 100°C, dividing his scale into 100 degrees using a decimal system.
What is the Kelvin Scale?
British physicist Lord Kelvin (born William Thomson, 1824–1907) proposed the Kelvin scale in 1848. Science uses this scale because it starts at absolute zero, making temperature readings proportional to the actual kinetic energy in a material. The Kelvin scale’s melting point for ice is 273 K, and its boiling point of water is 373 K, 100 units higher. Therefore, the size of one Kelvin unit is the same size as one Celsius degree.
How dose one take a standardized offical temperature reading?
Devices for taking standardized official temperature readings are placed outdoors in small shelters that are white (for high albedo) and louvered (for ventilation) to avoid overheating of the instruments (Figure 5.4). They are placed at least 1.2–1.8 m above the ground surface, usually on turf. Official temperature measurements are made in the shade to prevent the effect of direct insolation.
What is a thermistor?
Standard instrument shelters contain a thermistor, which measures temperature by sensing the electrical resistance of a semiconducting material.
What is land-surface temperature?
Satellites do not measure air temperature in the same way as thermometers; instead they measure land-surface temperature (LST), or land “skin” temperature, which is the heating of the land surface and is often much hotter than air temperature.
How dose latitude effect insolation and temperature?
Between the tropics, insolation is more intense than at higher latitudes, where the Sun is never directly overhead (at a 90° angle) during the year. The intensity of incoming solar radiation decreases away from the equator and toward the poles. Daylength also varies with latitude during the year, influencing the duration of insolation exposure. Variations in these two factors—Sun angle and daylength—throughout the year drive the seasonal effect of latitude on temperature
How dose altitude effect temperature?
From Chapter 3, remember that within the troposphere, temperatures decrease with increasing altitude above Earth’s surface. (Recall from Figure 3.3 that the normal lapse rate of temperature change with altitude is 6.5 C° ·1000 m−1.) The density of the atmosphere also diminishes with increasing altitude. In fact, the density of the atmosphere at an elevation of 5500 m is about half that at sea level. As the atmosphere thins, it contains less sensible heat. Thus, worldwide, mountainous areas experience lower temperatures than do regions nearer sea level, even at similar latitudes.
What is the difference between altitude and elevation?
Two terms, altitude and elevation, are commonly used to refer to heights on or above Earth’s surface. Altitude refers to airborne objects or heights above Earth’s surface. Elevation usually refers to the height of a point on Earth’s surface above some plane of reference, such as elevation above sea level. Therefore, the height of a flying jet is expressed as altitude, whereas the height of a mountain ski resort is expressed as elevation.
How dose cloud cover effect temperature?
The presence of cloud cover at night has a moderating effect on temperature; you may have experienced the colder temperatures outside on a clear night, especially before dawn, the coldest time of the day. At night, clouds act as an insulating layer that reradiates longwave energy back to Earth, preventing rapid energy loss to space. Thus, in general, the presence of clouds raises minimum nighttime temperatures. During the day, clouds reflect insolation, lowering daily maximum temperatures; this is the familiar shading effect you feel when clouds move in on a hot summer day. Clouds also reduce seasonal temperature differences as a result of these moderating effects.
Clouds are the most variable factor influencing Earth’s radiation budget, and studies are ongoing as to their effects on Earth’s temperatures.
