Humidity refers to the amount of water vapor present in the atmosphere. Its presence can be observed by filling a beaker with ice-cold water and leaving it at room temperature for a few minutes. Water droplets form on the outer surface as water vapor in the air comes into contact with the cold surface and condenses. This simple experiment demonstrates the presence of water vapor in the air.
Humidity of air
Humidity is defined as the concentration of water vapor in the air, or the amount of water vapor present in the air is called humidity. The gaseous state of water is known as vapor. If the air contains a huge amount of water vapor, the humidity will be high.Â
Here a question that anyone may ask is, what is normal air humidity? The normal humidity is between 30% and 50%, but we cannot see it with our naked eyes. The relative humidity is also an important topic to talk about. It is the relationship between the moisture content of air at a certain temperature.Â
The humidity of air depends upon the temperature and pressure of the surrounding area. The instrument that is used to measure humidity is known as a hygrometer. It was first made by Leonardo da Vinci in the 1400s. Later, Francesco Folli invented a more practical hygrometer in 1664.
Effects of high humidity
- Dehydration
- Heat exhaustion
- Fainting
- Heatstroke
- Causes hypothermia, etc
Effects of low humidity
- Bloody noses
- Itchy throat
- Static electricity
- Allergy and asthma
- Cracking wood and furniture, etc.
Types of Humidity
Absolute humidity, relative humidity, and specific humidity are the three most commonly used main humidity measures. Let us learn more about the three basic humidity measures in this article.
Relative Humidity
The humidity which is used to find the amount of water vapor content in the air is known as relative humidity. It can be defined as the amount of moisture in the air at a particular temperature to the maximum moisture air can withstand at the same temperature.Â
We can observe 100% relative humidity in rainy seasons. It is expressed in terms of percentage and is usually applied for weather forecasting.
The formula to calculate relative humidity is given below:
RH = (Actual Vapor Density / Saturation Vapor Density) × 100%
Absolute humidity
Absolute humidity describes the water content present in the air. It is expressed in cubic meters of air. It ranges from zero to nearly 30 grams per cubic meter. If the air contains a high amount of water vapor, it will automatically raise absolute humidity. The rate is usually expressed in terms of grams per cubic meter. The value generally ranges from 0 to 30 g/m3.Â
The formula to calculate absolute humidity is                      Â
ΔH = mHâ‚‚O / VnetÂ
where
- mHâ‚‚OÂ is the mass of water vapor and
- Vnet is the volume of the water and air mixture
Specific humidity
The ratio of the mass of the vapor and the mass of the mixture of air and vapor is known as specific humidity. They are highly used in the field of metrology.Â
The formula to calculate specific humidity is
q = mv / ma
where,
- mv is the mass of water vapor and
- ma is the total mass of the air parcel.
Wind Speed
The rate at which air is moving in a particular area is known as wind speed. They are atmospheric quantities caused by air moving from high to low pressure. Humidity and wind speed are highly related to each other. The speed at which air flows over the surface of water affects the rate of water evaporation. The speed of wind is measured by a cup anemometer.Â
Leon Batista Alberta is said to have invented the first anemometer around 1450, but later Robert Hooke developed their own version of the anemometer and was credited as the inventor. The high speed of wind decreases the level of humidity, and low wind speed causes a high level of humidity. They also affect our human body. As the wind increases, heat is carried away from the body, which lowers down both skin temperature and internal body temperature.
The rate at which air moves across the surface of water influences the rate at which water evaporates. As the wind blows, airborne water particles in the air are swept away.Â
The humidity of the air in the vicinity of this evaporation decreases, allowing additional water molecules to evaporate into the air. Wind may also affect the vapor pressure by quickly moving air and causing it to expand. This process takes place for more water vapor, and evaporation will continue as long as the wind blows.Â
Sample Problems
Problem 1: Why does ice change into the water when heated?
Solution:
Ice is solid matter thus it has a high melting point so, it changes into the water while heating.
Problem 2: How does wind speed affect the humidity of air?
Solution:
Bose-Einstein condensate and fermionic condensate are the states of matter which are very similar to each other because both are formed under low temperatures.
Problem 3: Where are strange matters found, and what are they made up of?
Solution:
Strange matters are composed of strange quarks which are mainly found in neutron stars and white dwarfs.
Problem 4: What is the relationship between pressure and humidity?
Solution:
The humidity is higher in low pressure because lower pressure allows the air mass to hold more amount of water in high altitudes. thus humid air is higher in low pressure and lowers in high pressure.
Problem 5: How does windspeed affect the humidity of the air?
Solution:
The speed at which air flows over the surface of water affects the rate of evaporation. Humidity depends upon the amount of vapor present in the air. so, the higher wind speed causes minimum evaporation of water and low humidity and lower wind speed cause maximum evaporation of water and high humidity.
Problem 6: What are the effects caused by high humidity in our body?
Solution:
High humidity causes problems like fainting, dehydration' heatstroke, hypothermia, etc in human bodies.