Weather is what is happening all around you. It is the current state of the atmosphere and the study of this is known as meterology and the people who study it, meterologists. When gathering information about the weather, scientists a variety of instruments and measurements to understand what is happening at present, and give any indications for the weather to come.
Thermometer:
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A barometer is an instrument used by scientists and is very important when trying to predict short term weather changes. For example, if the pressure of the air is quite low, the conditions for a thunderstorm are very likely, and when pressure increases, the skies should remain clear. A barometer is measured in millibars, abbreviated as mbar, or, occasionally, in millimeters of mercury or inches of mercury. There are three major types of barometers; an aneriod barometer, a mercury barometer, and a water-based barometer. For more information about the types of barometers click here. For more information about barometers in general, click here.
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Derived from the Greek word anemos meaning wind, anemometers are commonly used weather instrument and very important to unveiling the weather's M.O. Anemometers measure wind speed and there are two main types of them. Velocity anemometers are designed to measure the winds velocity and pressure anemometers were developed to measure the wind's pressure but either one can provide both measurements. There are several different types of velocity anemometes including the following; cup anemometers, windmill anemometers, hot-wire anemometers, laser doppler anemometers, ping-pong ball anemometers, and sonic anemometers. There are two types of pressure anemometers; plate and tube models. Anemometers are measured in meteres per second, written m/s or miles per hour, written Mph or, miles/hr. For more information about anemometes, click here.
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Hygrometers are used to measure the relative humidity of the atmosphere. Relative humidity is the difference between how much water the air is holding, and the maximum amount of which it could hold at the current temperature. Hygrometers should be calibrated yearly and when given two hours to stabilize, before taking measurements from it due to the fact that hygrometers have been delicately molded and are prone to inaccuracy. There are three types of hygrometers; mechanical, electrical, and cold-spot, also known as dew-point. These are available in both dial and digital models. Hygrometers are measured in percents. for example, if the air has an one hundred percent relative humidity measurement, the air is holding all the moisture it can at the time given the temperature. For more infromation about hygrometers, click here.
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A psychrometer ia a type of hygrometer and one of many instruments used for measuring the water vapor content or relative humidity of the atmosphere. Psychrometers consist of two nearly identical thermometers—a wet-bulb thermometer containing a piece of cloth to be saturated with water, hence the name, and a dry-bulb thermometer. So when the cloth is soaked and the thermometers are being ventilated pproperly, the wet-bulb temperature will be lower than the dry-bulb temperature-- which is the actual temperature of the air because it is not being manipulated like the wet-bulb-- because the evaporation taking place will cool it. . Therefore, the drier the air is, the greater the evaporation taing place and the more depressed the wet-bulb becomes. Psycrhometers are measured in percents just like hygrometers. There are two types of psychrometers; an aspiring psychrometer and a sling psychrometer. For more information about psychrometers, if you wish, click here.
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A rain gauge is an instrument measure the amounts rainfall during a certain period of time.. Rain gauges are measured in, most commonly, millimeters, but occasionally in centimeters and inches as well. The different types of rain gauges include graduated cylinders, weighing gauges, tipping bucket gauges, buried pit collection, and optical rain gauges. Rain gauges have some disadvantages though, for example it is nearly impossible to record anything during a hurricane.. For more information about rain gauges, click here..
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A hydrometer is the instrument you want to use if you want to find the specific gravity of a liquid. To use a hydrometer, you want to pour whatever liquid you are testing into a tall glass and stick the hydrometer in it. Hydrometers are usually made of glass, and weighted with lead or mercury in a bulb on the end od a cylindrical stem. Inside a hydrometer, there is usually a paper scale to note the surface of when the hydrometer is first dropped into the substance. There are many different types of hydrometers including a lactometer to measure the amount of milk in mixtures, an alcoholometer is used to measure the alcoholic strength of liquids, and a saccharometer to measure the amount of sugar in a soultion. Specific gravity is measured in weight per unit volume compared with water.
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Clouds:
There are three major types of clouds. They are Cirrus clouds, Cumulus clouds, and Stratus clouds. For more information about clouds, click here.
The word stratus comes from the Latin word that means "to spread out." Stratus clouds lay horizantally and stretch to cover the sky. Whenever a layer of warm, moist air passes over a layer of cool air, stratus clouds often form wher ethese two layers meet. Where ever these layers are, the warm is cooled there and if it is cooled below its dew point, the excess water vapor condenses to form these clouds.
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Cumulus clouds are name after the Latin word for a heap or a pile. These clouds appear to be puffy and resemble large cotton balls. When warm, moist air is forced upward, cumulus clouds usually form. But as this warm air rises, it is being cooled. And if it is cooled past its dew-point temperature, condensation will occur. Depending on the force of the upward movement of air and the amount of moisture in the air, this determines the size of a cumulus cloud. The largest of cumulus clouds are the results of a very strong upward movement of warm, moist air. Cumulonimbus clouds are the type that cause heavy thunderstorms in the summer and are a form of cumulus clouds. These clouds can extend upward for hundreds of meters.
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Cirrus clouds are the last type of clouds. The word Cirrus comes from the Latin word for a tuft or curl of hair. Cirrus clouds are very wispy just as their name suggests and occasionally resemble a feather. These clouds can form only at high altitudes that are about seven kilometers above the Earth's surface. Cirrus clouds are so thin, sunlight can pass right through them and they are composed of ice crystals.
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