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Scientific Instruments Used in Agriculture Lysimeter - water loss from soil Rain gauge - from rainfall Anemometer - speed of wind Lactometer - and density of milk Aerometer - weight and density Barometer - atmosphere pressure Barograph - automatic measurement of change in pressure Cresco-graph - recording growth of plants Hydrometer - specific gravity of water Hygrometer - and relative humidity in atmosphere A lysimeter is most accurate when vegetation is grown in a large soil tank which allows the rainfall input and water lost through the soil to be easily calculated. The amount of water lost by evapotranspiration can be worked out by calculating the difference between the weight before and after the precipitation input. A rain gauge (also known as an udometer, pluviometer, or an ombrometer) is an instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a set period of time. Wind vanes measure wind direction and are often used with anemometers, which measure wind speed. Types - cup, propeller, ultrasonic, sonic, and lidar. The lactometer is a special type of hydrometer. It is constructed and graduated so that the lactometer reading is related to the specific gravity of milk on the ratio of the milk to water weight of a unit volume at a specified temperature. The Aerometer is a glass body which is dipped into the sample. After a short equilibration time it will swim at a certain level (when the mass of the Aerometer is equal to the buoyancy effect). The higher the density of the sample, the less the aerometers will sink. The level of equilibration reads the density on the calibrated scale. The fundamental SI unit of pressure is the Pascal (Pa), but it is a small unit so kPa is the most common direct pressure unit for atmospheric pressure. Since the static fluid pressure is dependent only upon density and depth, choosing a liquid of standard density like mercury or water allows you to express the pressure in units of height or depth, e.g., mmHg or inches of water. Barograph, instrument used to make a continuous recording of atmospheric pressure. The pressure-sensitive element, a partially evacuated metal cylinder, is linked to a pen arm in such a way that the vertical displacement of the pen is proportional to the changes in the atmospheric pressure. The pen traces a record of pressure versus time on a chart, which is mounted on a drum rotated by a clockwork. Each chart usually provides one week's record.  A crescograph is a device for measuring growth in plants. It was invented in the early 20th century by Sir Jagadish Chandra Bose  The Bose crescograph uses a series of clockwork gears and a smoked glass plate to record the movement of the tip of a plant (or its roots) at magnifications of up to 10,000. Marks are made on the plate at intervals of a few seconds, demonstrating how the rate of growth varies under varying stimuli A hydrometer is an instrument that measures the specific gravity (relative density) of liquids—the ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright. The liquid to test is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to specific gravity.. Humidity is the amount of water vapor in the atmosphere caused by condensation and evaporation. It can be measured as absolute humidity (the amount of water vapor in a unit volume of air), or as relative humidity (the ratio of moisture in the atmosphere to the maximum moisture the atmosphere can hold). Humidity measurement instruments usually rely on measurements of some other quantity such as temperature, pressure, mass or a mechanical or electrical change in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can lead to a measurement of humidity.  Thanks for Watching Subscribe for More videos like on fb: https://www.facebook.com/Advance-Agricultural-Classes-209935129434632/ join our fb group: https://www.facebook.com/groups/1600626926901456/