Science 2023

Geographic instruments are devices that help to find out data in various areas of our environment. Such devices are needed literally to measure every single natural phenomenon, and they bring benefits to all people on our planet.

## How do they measure the temperature of air, soil and water?

Geographical studies of air, soil and water temperatures are carried out using three types of instruments. All of them are called thermometers, but they are arranged in different ways.

The principle of operation of liquid thermometers is to determine the change in temperature based on an increase or decrease in the volume of liquid in them. The liquid used in these thermometers is usually either mercury or alcohol.

Deformation thermometers work on the basis of the interaction of two different metals in them. A bimetallic alloy plate deforms differently because the metals used have different coefficients of expansion. As a rule, the plate is made of steel and Invar. Invar is an alloy, not a single metal. And they create it from nickel and iron.

Electric thermometers measure temperaturebased on the interaction of various bodies with electricity, changes in their electrical conductivity when exposed to temperature.

## How is air humidity measured?

In order to measure the humidity of the air, three types of different geographical instruments are also used.

With the help of a condensation hygrometer, conditions of the so-called dew point (100% humidity) are created at a small point. And they measure the real state of affairs based on the difference in humidity indicators on the street and in the device. An inert gas helps create dew point conditions as it evaporates and condenses very quickly.

Psychrometer simultaneously measures both humidity and temperature. This instrument consists of two identical thermometers, one of which is always dry and the other wet. Therefore, they give different indications. So, using the data from the measurement table for this device, you can determine not only the temperature, but also the humidity.

The hair hygrometer uses human hair or a special artificial film. These items are able to change their length depending on the level of humidity in the air. And, deforming, they move along the scale, showing all the necessary data.

## How is atmospheric pressure measured?

Geographic pressure surveys are done with barometers. There are four types of such devices: liquid, mercury, electronic and aneroid.

Liquid barometer is two tubes,which are communicating vessels. And based on the change in the state of the liquid that is poured into them, conclusions are drawn about what atmospheric pressure is at the moment. Fill these tubes with mercury, oil or glycerin. Cup and siphon barometers also work based on the properties of the liquid.

A mercury barometer is also a tube that works on the principle of communicating vessels. One of the ends of this tube is sealed, and there is a float on the surface of the mercury. And based on where it stops on the scale, millimeters of mercury are measured.

Electronic barometer - one of the modern geographical instruments - has a programmed microprocessor that shows the level of atmospheric pressure, displaying data on the screen. Such a device receives this data through an aneroid.

Aneroid barometer - differs from liquid and mercury in that it monitors changes in the state of the metal under the influence of a particular pressure.

## How do you measure wind speed and direction?

Several varieties of geographic instruments and instruments also exist for measuring wind speed and direction.

The simplest of them is a weather vane. It measures the desired indicators above the ground (10-12 meters). The weather vane must be highly mobile in order to measure even very light winds.

Tretyakov's windmeter has the same principle of operation as a weather vane, but is used to measure the wind in the fields. This is because in open areas the wind speed can differ significantly from that in more enclosed areas.spaces.

Anemorumbometer is a more advanced and modern device. It measures wind speed and direction and converts them into electrical quantities.

Anemometer measures wind only at medium speed (from 1 to 20 m/s). This is a manual device.

## How is precipitation measured?

Precipitation refers to all the water that falls on the surface of the earth. They are liquid (rain, dew) and solid (snow, hail, hoarfrost, ice, snow pellets). They are measured in such a way as if they fell on a flat surface, without soaking into the ground. Three types of geographic instruments help calculate precipitation: the Tretyakov rain gauge, the M-70 total rain gauge and the pluviograph.

The Tretyakov rain gauge is designed to measure both liquid and solid precipitation. Its principle of operation is that in a capacity of 200 square meters. see precipitation flows, and a specially arranged protection prevents it from blowing out and evaporating.

The total rain gauge is used to measure annual precipitation. It consists of a cone-shaped part where precipitation enters, as well as a special removable pipe that closes with a valve. In order to prevent the collected precipitation from evaporating, a small amount of mineral oil is poured into this rain gauge. It covers the resulting liquid with a film.

Pluviograph is a complex device that measures precipitation independently and records the results itself. It works like this: when a flask with many tubes reaches a certain limit, the liquid from the pluviograph is drained into a bucket, and the programmedthe machine records the results.

## What else is measured and with what instruments?

In addition to these obvious natural factors, radiation measurements from the Sun, the Earth and the atmosphere are also underway. For this, geographic devices are used, such as:

• Pyrheliometer (measures direct solar radiation).
• Heliograph (measures the duration of sunshine).
• Pyrgeometer (a device for measuring the effective radiation of the earth's surface).
• Balance meter (used to measure the difference between the inflow and outflow of radiant energy).
• Actinometer (measures the intensity of electromagnetic radiation).
• Albedometer (photometric device for determining flat albedo).
• Pyranometer (used to measure solar radiation).
• Pyranograph (device for continuous recording of solar radiation).

Visibility is also measured (with a nephelometer), elementary atmospheric electricity (with an electrometer), etc.