The Functions and Uses of a Hygrometer
You may have heard your elders sometimes say that “the air is humid” when you feel too hot, and your skin feels too sticky. The air’s humidity means that the air has moisture in it. The higher the amount of moisture, the higher the humidity.
So you may wonder, "How does anybody know if the humidity is higher or lower?" Therefore, a hygrometer device was invented way back in the 1400s by none other than Leonardo da Vinci. Although it has been modified and re-developed by many people, the credit goes to him. The hygrometer measures the relative humidity of the air. Now let us learn more about the hygrometer.
What is a Hygrometer?
As you have learnt above, a hygrometer is a device that measures the relative humidity of the air. You know that everything has some capacity. Similarly, the air has a particular capacity for moisture. Therefore, relative humidity compares the amount of moisture present in the air with the maximum amount of moisture that the air can hold. Hygrometers are used for various purposes.
10 Uses Of Hygrometer
Used To Find the Relative Humidity
As you have already learnt above, relative humidity is all about the amount of moisture in the air concerning its capacity. A hygrometer measures this humidity.
For Measuring Moisture Levels
A hygrometer is used to measure the moisture levels in the air. The measurement of relative humidity helps understand the atmosphere's moisture levels.
Water Vapour in a Mixture of Gases
Suppose a mixture of gases is being used for industrial purposes. Will it always have pure gases? No, because sometimes, water vapour remains, after chemical reactions, in the gaseous mixture. Therefore, measuring the amount is necessary to keep the water vapour levels in check, which is done by the hygrometer.
Used in Various Industrial Processes
The hygrometer is used in industries, especially when something is being produced. humidity levels can alter the nature of the things produced. Therefore, the hygrometer plays an important role in checking the industrial environment's humidity.
Weather Forecasting
Humidity levels are also a part of weather forecasting. Therefore, a hygrometer is used by weather forecasters to give the right information to the viewers.
Used in Saunas
Saunas are places that are filled with hot steam. People usually go to these places for cleansing and to refresh themselves. Therefore, in such places, temperature and humidity control is significant. Hence, hygrometers are used in saunas to check the humidity levels.
Used in Incubators
Incubators are where pre-mature babies are kept so they stay in a controlled environment for their care. These incubators also use a hygrometer to check the moisture levels and keep them balanced for the babies.
Used for Wooden Musical Instruments
You must have noticed that in the rainy season, wooden doors and windows usually do not close easily. This is because the wood absorbs the high moisture content of the air. The same happens with wooden musical instruments like violins, guitars, flutes, etc. Therefore, the humidity must be controlled to prevent damage to such instruments. The hygrometer becomes very useful in such places.
Used in Museums
Museums contain antique and ancient objects like old manuscripts, etc. The hygrometer is used to check the moisture level in the air, which helps preserve ancient goods.
Used While Preserving Food
Moisture in the air can lead to the growth of microorganisms like fungi in food. This can cause damage to food products, so moisture in the air must be controlled to prevent damage. Hence, hygrometers are used in the food industry to check moisture levels while preserving food.
Conclusion
Isn’t it fascinating that the moisture present in the air can affect our lives in so many ways? And hygrometers play an important role in helping us check the moisture levels and humidity in the air. So, today you have learned about humidity, hygrometers, and the main uses of a hygrometer. You have learnt that hygrometers are devices that help us measure the relative humidity in the atmosphere. As humidity affects many life processes, it is used in industries such as the food industry for controlling the environment's conditions, in hospitals, etc.
FAQs on The Uses of Hygrometers
1. What is a hygrometer and what does it measure?
A hygrometer is a scientific instrument used to measure the amount of water vapour in the air, in soil, or in confined spaces. This measurement is known as humidity. It is crucial for weather forecasting and in many industrial and commercial applications.
2. What are some common uses of a hygrometer?
Hygrometers have a wide range of applications in various fields. Some of the most important uses include:
- Weather Forecasting: To measure humidity levels to help predict rain, fog, or dew.
- Greenhouses and Agriculture: To maintain optimal moisture levels for healthy plant growth and prevent diseases.
- Museums and Archives: To protect sensitive artefacts like old books, paintings, and documents from damage caused by improper humidity.
- Manufacturing: In industries like food processing, textiles, and electronics where controlling moisture is critical for product quality.
- HVAC Systems: To regulate humidity in homes and commercial buildings for human comfort and health.
- Incubators: For hatching poultry eggs, which require very specific and stable humidity levels to develop properly.
3. How does a simple hygrometer work?
The working principle of a hygrometer depends on its type. A basic mechanical hygrometer, for instance, often uses an organic material like human hair or a coiled metal strip. This material naturally expands when it absorbs moisture from the air and contracts when the air becomes dry. This tiny physical change is linked to a spring and needle, which moves across a calibrated dial to show the relative humidity level.
4. What are the main types of hygrometers?
There are several types of hygrometers, each operating on a different scientific principle. The four main types students learn about are:
- Mechanical Hygrometers: Use organic materials (like hair) that physically change size with humidity.
- Electrical (or Digital) Hygrometers: Measure changes in the electrical resistance or capacitance of a moisture-absorbing material.
- Psychrometers (Wet-and-Dry-Bulb Hygrometers): Determine humidity by comparing the temperature readings of a wet-bulb and a dry-bulb thermometer.
- Dew Point Hygrometers: These are highly accurate devices that measure the exact temperature at which dew begins to form on a cooled, polished surface.
5. What is the unit of measurement for a hygrometer?
A hygrometer primarily measures relative humidity (RH). This value is expressed as a percentage (%). For example, a reading of 100% RH indicates that the air is completely saturated with water vapour and cannot hold any more at that temperature, which often leads to rain or fog.
6. How can you test if a hygrometer is accurate at home?
A simple way to check a hygrometer's accuracy is the damp cloth method. You can carefully wrap the hygrometer's sensor in a moist cloth for about 30-40 minutes. A perfectly accurate device should read very close to 100% humidity. Most home hygrometers are considered to be working well if they provide a reading between 90% and 95% in this test.
7. Why is a psychrometer considered one of the most accurate types of hygrometers?
A psychrometer is highly accurate because it relies on a stable physical principle called evaporative cooling. It directly measures the temperature drop caused by water evaporating from its wet bulb. The rate of this evaporation is directly and predictably linked to the air's humidity. Since it is based on precise temperature measurements rather than the less consistent physical changes in materials (like in mechanical hygrometers), it provides a more reliable and precise reading.
8. Beyond weather forecasting, in which specific industries are hygrometers essential?
Hygrometers are critical in many high-tech and sensitive industries where moisture can severely affect product quality, safety, or operations. For example, in data centres, high humidity can cause corrosion on server parts, while low humidity can create static electricity that damages electronics. Similarly, in the pharmaceutical industry, hygrometers ensure that medicines are manufactured and stored in stable conditions to maintain their chemical integrity and effectiveness.
9. What is the difference between a hygrometer and a hydrometer?
Although their names sound very similar, a hygrometer and a hydrometer are used to measure completely different properties. A hygrometer measures the amount of moisture or humidity in the air (a gas). In contrast, a hydrometer is an instrument used to measure the density or specific gravity of a liquid, such as checking the sugar content in juice or the charge of a car battery's acid.
10. Who is credited with inventing the hygrometer and what was the principle of the earliest models?
While many scientists worked on measuring humidity, Leonardo da Vinci is often credited with designing the first rudimentary hygrometer in the 1480s. His invention worked like a balance scale. One side held an absorbent material like a ball of wool, while the other side held an equal weight of a non-absorbent material like wax. As the wool absorbed moisture from the air, it became heavier, causing the scale to tip and thus indicating a change in humidity.
