The weather is based on the observation and measurement of certain factors such as temperature, atmospheric pressure and humidity, among others. To make this work, certain instruments are used.

With advances in technology, measurement instruments have been developed and created some new ones. This allows measurements are becoming more precise and can be made further in advance.

Barometer

It is an instrument used to measure atmospheric pressure, ie weight exercising the atmosphere on the earth's surface. The low pressures are indicative of bad weather.

The units of measurement are used by the barometers milibares or hectopascals. This instrument was invented in the seventeenth century by the Italian Evangelista Torricelli.

Thermometer

This instrument used to measure temperature generally degrees centigrade. Other measures are the Kelvin temperature and degrees Fahrenheit.

The thermometer most common until now has been that of mercury, invented in the eighteenth century. Currently the most sophisticated are digital. There are special thermometers, for example, to record the minimum and maximum temperatures.

Hygrometer

It is an instrument used to measure moisture, ie, the amount of water vapor there is in the air at any given time. The amount of moisture is usually expressed as a percentage, which means that there is that portion in each cubic centimeter of air.

Typically they consist of materials that easily absorb moisture, leading to its expansion and consequent increase in size.

Anemometer

This is an instrument used to measure the wind speed. It is usually expressed in mph, although navigation is also used another unit called the knot, which is equivalent to 1.85 km/h.

The anemometers are used to measure wind speed and sudden changes in the same direction. The most common is that registers turns heavy wind causes about a kind of mill.

Rain

It is an instrument used to measure the amount of rain that falls in one place. Given the extent of use milliliter, each equivalent to one liter per square meter.

Normally it is a container that collects rainwater, whose measure is recorded every time periods stipulated that can be in many cases 10 or 12 hours.

Other instruments weather

·  Vane: simple and very ancient instrument used to indicate the direction of the wind which is expressed as the cardinal points.

·  Radar: used for weather serves to locate the presence of large distance rains, storms and other phenomena.

·  Radiosonda: Weather is a tool that is used to assess the atmospheric conditions (wind, temperature, etc.). In the upper atmosphere. The radiosondes rise to these layers in helium balloons.

·  Artificial Satellites: they are launched into orbit, and from there, in addition to other duties collected images of the Earth. These are received by the weather stations for study.