A hygrometer is a device that is widely used in weather forecasting or climatology. It measures the percentage of humidity in the atmosphere. The greater value of humidity if more vapors are in the atmosphere. Similarly, it precisely gives the relative humidity value and during the summer its value increases due to an increase in precipitation of more water.
Relative humidity measurement is very important because the temperature and humidity are related to the health of people. The working principle of this device is based on temperature and vapor pressure. Moreover, hygrometers are widely used in the industries to check the humidity level in the storage room of industries because all the finished products need a specific humidity level. Hygrometers are of different types such as electrical hygrometer whose working principle is a change in electrical potential of any semiconductor device.
Methods to make Hygrometer
There are different hygrometers to construct easily but you can make hygrometer with hairs and wet-dry hygrometer easily at home. In hair hygrometer, humidity level causes contraction or expansion of hairs that can cause movement of the needle on the measurement device
1. Collect all Required Material
To make a hair hygrometer first of all collect all necessary materials like scale, marker, scissor to cut the cardboard, hairs, glue, hairdryer, and all these material are either available at home or obtained from a stationery shop. Moreover, precaution is compulsory when it comes to using a hammer for needles.
2. Clean Hair in Water and Alcohol Solution
In the first step, clean hairs in the glass containing few drops of water and two drops of alcohol that will remove dirt or oils from the hairs. In the second step, remove them from the mixture and dry on a paper with the help of a hairdryer. This process is necessary because only clean and dry hair will absorb water and give accurate relative humidity value.
3. Make arrow on cardboard and cut with scissors
After that, draw a small arrow on the clipboard and cut it with the help of scissors. Make a small hole at the tip of the arrow and insert the pin in the hole in such a way arrow move freely on the cardboard. You can check the movement of the arrow by moving tit with hand and if it does not move you can lose the pin to make it freely movable.
4. Tape the Hair to the Arrow and Cardboard
After that with the help of glue or tape attach the clean dried hair with an arrow on one side and cardboard on others in perpendicular direction.
5. Calibration of Hygrometer
Furthermore, calibrate the hygrometer with the help of a pencil. For calibration, you need to draw marking around the arrow and divide it into ten portions making it a total of 100 percent. In addition to this, mark one side of marking as dry and another side humid. If the humidity level in the air increases the arrow will point toward the humid side on the scale. The hair has some kind of flexibility and property to expand upon absorbing moisture and contract in the hot environment. So, when there is an increase in vapors in air, the arrow will move towards the humid side on the scale. Similarly, when air is dry, it will remain towards the drier side.
In wet dry hygrometer, two thermometers are used, one is dry which measures air temperature, while the other is wet along which wet cloth is wrapped. Therefore, when air moves the water vapors evaporate and the difference between the two thermometers gives relative humidity value.
1. Collection of Required Material
First of all, collect all necessary material required to make this hygrometer including a cotton pad, a small band of rubber, a temperature-sensitive device like a thermometer, and large cardboard to support two thermometers. Also, there is a need for a small vessel and some quantity of water is also necessary to make dry/wet hygrometer.
2. Cover bottom tip of the thermometer with wet cotton
First of all, take a small quantity of water in the vessel and put small cotton gauze pieces into it. Keep the cotton in water for enough time to absorb water in it. After that, wrap the moist cotton at the bottom tip of the thermometer and fix it with the help of a small rubber band. For the proper measurement of humidity, this cotton should remain wet during the whole procedure.
3. Fix Thermometer on Cardboard
Fix dry and wet thermometer on the cardboard at some distance but their level should remain the same. It can be fixed by using tape or glue. Special precautions are compulsory when it comes to using hot glue.
4. Note down reading on both Thermometers
With the help of dry/wet hygrometer, we can determine the percentage of vapors pressure in the atmosphere. Moreover, note down the reading on the dry and wet thermometer at different intervals of time and note these temperatures.